Co-reporter:Yi-Jing Wang;Li Chen;Xiao-Tao Zheng;Sha-Sha Xu;En-Bo Wang
Inorganic Chemistry Frontiers 2017 vol. 4(Issue 3) pp:559-565
Publication Date(Web):2017/03/14
DOI:10.1039/C6QI00570E
Sandwich-type polyoxometalates K6Na2Ni2[Ni4(H2O)2(SiW9O34)2]·30H2O(Ni4), K6Na2Co2[Co4(H2O)2(SiW9O34)2]·30H2O(Co4) and K10[Ni(H2O)2(γ-SiW10O35)2]·13.25H2O(Ni1) were doped into TiO2 separately and applied as photoanodes for dye-sensitized solar cells (DSSCs) for the first time, enhancing the current intensity and photoelectric conversion efficiency of the cells. The TiO2 and POM@TiO2 used in this paper were synthesized by a modified sol–gel method. The Jsc of pure P25 is 15.84 mA cm−2, the Voc is 0.637 V, the FF is 0.564, and the η is 5.69%. The Jsc of the prepared TiO2 is 16.48 mA cm−2, the Voc is 0.68 V, the FF is 0.537 and the η is 6.01%, which is a higher efficiency than that of pure P25, therefore the POMs@TiO2 were directly used in photoanodes without being formed into composites with P25 in this paper. The Jsc of 0.8% Ni4@TiO2 is 18.79 mA cm−2, the Voc is 0.71 V, the FF is 0.595 and the η is 7.94%, which is 32.1% higher than that of the prepared TiO2 based DSSC. 0.8% Co4@TiO2 and 0.8% Ni1@TiO2 modified photoanodes obtained power conversion efficiencies of 6.22% and 6.17%. The electron lifetimes of the self-prepared TiO2 and 0.8% Ni4@TiO2 are 13.5 ms and 28 ms respectively, calculated from a bode plot. Among the three kinds of sandwich-type POMs mentioned in this paper, the 0.8% Ni4 modified photoanode in DSSCs exhibited the best performance in enhancing light harvesting and reducing electron recombination. The energy levels of Ni4 were also investigated.
Co-reporter:Xiang-Wei Guo;Xiao-Hong Li;Zhu-Jun Liu;Xiao-Tao Zheng;En-Bo Wang;Zhong-Min Su
Inorganic Chemistry Frontiers 2017 vol. 4(Issue 7) pp:1187-1191
Publication Date(Web):2017/07/11
DOI:10.1039/C7QI00160F
Photosensitizers play a crucial role in p-type dye-sensitized solar cells (p-DSSCs). In this study, we first introduced two Dawson-type transition metal-substituted polyoxometalate dyes to co-sensitize the NiO electrode and achieved an overall power conversion efficiency (PCE) of 0.0464%, which is the highest value reported for inorganic photosensitizers in p-DSSCs.
Co-reporter:Jiabo Wang, Weilin Chen, Xinlong Wang, Enbo Wang
Electrochimica Acta 2017 Volume 251(Volume 251) pp:
Publication Date(Web):10 October 2017
DOI:10.1016/j.electacta.2017.08.151
•WxC/NG-10 was synthesized via a simple two-step calcination method.•WxC/NG-10 exhibited the highly efficient and long-term stable electrocatalytic hydrogen evolution reaction.•WxC/NG-10 was firstly attempted to apply to OER.Tungsten carbides materials exhibit highly efficient activity for hydrogen evolution reaction (HER) as promising non-precious electrocatalysts. Herein, a N-doped graphene (NG) supported tungsten carbides composite material (WxC/NG-10, x = 1, 2, x is stoichiometric number of W, 10 is the mole quantity of tungsten in the precursors, mmol) was directly synthesized with a simple method by two-step calcining the mixture of sodium tungstate dihydrate (Na2WO4·2H2O), dicyandiamide (DCDA) and glucose anhydrous (GA), which was characterized by HRTEM, FE-SEM, XRD, XPS, EDX, BET and Raman, and estimated the electrocatalytic activity by the LSV, Tafel curves, and electrochemical impedance spectrum (EIS). The investigations indicate that WxC/NG-10, as an electrocatalyst for HER, achieves a lower overpotential of only 77.82 mV at the current density of 10 mA cm−2 and a Tafel slope of 45.95 mV dec−1 in 0.5 mol L−1 H2SO4 aqueous. Additionally, the WxC/NG-10 has also possessed an electrocatalytic oxygen evolution reaction (OER) activity in 1.0 mol L−1 KOH aqueous with a lower overpotential of 467.6 mV and a Tafel slope of 36.2 mV dec−1. And after 10000 cycles the electrocatalytic active of WxC/NG-10 decrease 24.63% and 19.35% for HER and OER, respectively. The modification of WxC has improved the activity of NG materials in electrocatalytic applications.A N-doped graphene supported WxC composite material is directly synthesized by a simple two-step calcination method, which enhances the electrocatalytic HER activity and firstly tries to apply to OER.Download high-res image (243KB)Download full-size image
Co-reporter:Chun-Hui Shan, Hong Zhang, Wei-Lin Chen, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 9) pp:3297-3303
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5TA10601J
A pure inorganic donor–acceptor (D–A) type polyoxometalate K6H4[α-SiW9O37Co3(H2O)3]·17H2O (SiW9Co3)/reduced graphene oxide (RGO) nanocomposite was employed to dye-sensitized solar cells (DSSCs) for the first time, building up a wide spectrum for the photoanode of a DSSC. Raman, XRD, TEM, and EDS have proved that SiW9Co3 was loaded on RGO, and then the SiW9Co3/RGO doped nanocomposite in P25 was applied to be the photoanode of the DSSCs. In this paper the performance of SiW9Co3/RGO-3@P25 is the best. The Jsc of pure P25 is 13.74 mA cm−2, Voc is 0.679 V, FF is 0.598 and η is 5.37%, while the Jsc of SiW9Co3/RGO-3@P25 is 17.5 mA cm−2, Voc is 0.705 V, FF is 0.558 and η is enhanced to 6.88%, which is 28.05% higher than for a pure P25-based cell in a DSSC. OCVD indicates that SiW9Co3/RGO can delay the electron–hole recombination. In a Bode plot the electron lifetimes of SiW9Co3/RGO-3@P25 and P25 are 4.86 ms and 3.81 ms respectively, which also further clarifies that the SiW9Co3/RGO doped nanocomposite can extend the lifetime of electrons and also plays an important role in the photoanode of the DSSCs. This result is beneficial to the application of DSSCs in future industry.
Co-reporter:Li Chen, Weilin Chen, Huaqiao Tan, Jiansheng Li, Xiaojing Sang and Enbo Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 11) pp:4125-4133
Publication Date(Web):10 Feb 2016
DOI:10.1039/C5TA10260J
Quantum dot sensitized solar cells with high theoretical conversion efficiency, low production cost and a simple production process have received great attention in recent years. For CdSe-sensitized cells, the most significant defect of CdSe is that it has the weak absorption between 550 and 600 nm and no absorption after 650 nm, so it is crucial to find a wide spectrum photosensitizer to make up for the defect. Here, wide spectrum and pure inorganic Donor–Acceptor (D–A) Type Polyoxometalate (POM) K6H4[α-SiW9O37Co3(H2O)3]·17H2O (denoted as T) is firstly introduced into QDSCs as a collaborative cosensitizer with CdSe. The T has a visible characteristic peak centering between 550 and 600 nm, and also has stronger absorption after 650 nm, which could make up for the defect of CdSe to constitute a wide spectrum of absorption. The fluorescence spectrum, surface photovoltage spectrum, ultraviolet photoelectron spectroscopy spectrum and solid diffuse spectrum were used to explore the photosensitivity of T. In addition, the D–A type POM can act as a good intermediate for the injection of electrons and improve the visible photocurrent response; meanwhile, it can obviously reduce the dark current and increase the electron lifetime, which can solve the problem about the high recombination at the QD/TiO2/electrolyte interface. In general, the best photovoltaic performance of T and CdSe cosensitized solar cells is increased to 6.59% (Jsc = 18.37 mA cm−2, Voc = 0.57 V, FF = 0.63), which is improved by 32.33% compared to those of the pure CdSe-sensitized cells (Jsc = 16.20 mA cm−2, Voc = 0.50 V, FF = 0.61, η = 4.98%).
Co-reporter:Lifei He, Li Chen, Yue Zhao, Weilin Chen, Chunhui Shan, Zhongmin Su, Enbo Wang
Journal of Power Sources 2016 Volume 328() pp:1-7
Publication Date(Web):1 October 2016
DOI:10.1016/j.jpowsour.2016.07.085
•Highly dispersed POM nanoparticles were synthesized by micelle directed method.•TiO2 composited with POM nanoparticles was studied as photoanodes.•Both high dispersion and nanoscale increased the active site.•POM addition accelerated electron transition and retarded electron recombination.•The composite yielded an efficiency improvement from 5.9% to 8.4%.In this work, two kinds of polyoxometalate (POM) nanoparticles with controlled shapes and structures were synthesized by micelle directed method and then composited with TiO2 via calcination to remove the surfactants owing to the excellent electronic storage and transmission ability of POM, finally obtaining two kinds of TiO2 composites with highly dispersed and small-sized POM nanoparticles (∼1 nm). The TiO2 composites were then induced into the photoanodes of dye-sensitized (N719) solar cells (DSSCs). The separation of electron-holes becomes more favorable due to the nanostructure and high dispersion of POM which provide more active sites than pure POM tending to agglomeration. The TiO2 composite photoanodes finally yielded the power conversion efficiency (PCE) of 8.4% and 8.2%, respectively, which were 42% and 39% higher than the pristine TiO2 based anodes. In addition, the mechanisms of POM in DSSC are proposed.Two polyoxometalate (POM) nanoparticles with controlled shape and structure were synthesized by micelle directed method, and then composited with TiO2 via calcination to remove the surfactant to obtain TiO2 complexes with highly dispersed and small-sized polyoxometalate nanoparticles, which were firstly applied as photoanodes for dye-sensitized (N719) solar cells with enhanced photovoltaic performance.
Co-reporter:Dr. Xiang-Wei Guo;Dr. Jian-Sheng Li;Dr. Xiao-Jing Sang; Wei-Lin Chen; Zhong-Min Su ; En-Bo Wang
Chemistry - A European Journal 2016 Volume 22( Issue 10) pp:3234-3238
Publication Date(Web):
DOI:10.1002/chem.201504497
Abstract
In light of the serious challenge of severe global energy shortages, p-type dye-sensitized solar cells (p-DSSCs) have attracted increasing levels of interest. The potential of three Keggin-type transition metal-substituted polyoxometalates, TBA8Na2[SiW9O37{Co(H2O)3}]⋅ 11 H2O (SiW9Co3), TBA4[(SiO4)W10MnIII2O36H6]⋅1.5 CH3CN⋅ 2 H2O (SiW10MnIII2), and TBA3.5H5.5[(SiO4)W10MnIII/IV2O36]⋅ 10 H2O⋅0.5 CH3CN (SiW10MnIII/IV2) has been explored as pure inorganic dye photosensitizers for p-DSSCs (TBA=(n-C4H9)4N+). The three dyes show overall conversion efficiencies of 0.038, 0.029, and 0.027 %, respectively, all of which are higher than that of coumarin 343 (0.017 %). These polyoxometalates are the first three pure inorganic dyes reported for use with p-DSSCs and therefore demonstrate a new strategy for designing efficient dyes, especially pure inorganic dyes. Moreover, they broaden the range of applications for polyoxometalates.
Co-reporter:Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Lan-Cui Zhang, Zai-Ming Zhu, Yang-Guang Li, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 28) pp:14573-14577
Publication Date(Web):12 Jun 2015
DOI:10.1039/C5TA03259H
A strategy was developed for the first time to fabricate highly dispersed and small-sized polyoxometalate nanoparticles loaded on a TiO2 film by using MIL-101 to prevent agglomeration, and calcination to break the metal–organic framework, which can result in performance improvement of quantum dot solar cells.
Co-reporter:Dan Xu, Wei-Lin Chen, Jian-Sheng Li, Xiao-Jing Sang, Ying Lu, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 19) pp:10174-10178
Publication Date(Web):31 Mar 2015
DOI:10.1039/C5TA01578B
SiW11V/graphene nanocomposite was first prepared and introduced into TiO2 film. It showed a significant photocurrent response, which can be attributed to the photoinduced electrons of SiW11V. This work provides a promising strategy for exploring POMs sensitizers with lower energy levels than the CB of TiO2.
Co-reporter:Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Lan-Cui Zhang, Zai-Ming Zhu, Teng-Ying Ma, Zhong-Min Su, and En-Bo Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 24) pp:13714
Publication Date(Web):June 1, 2015
DOI:10.1021/acsami.5b03948
In the field of material chemistry, it is of great significance to develop abundant and sustainable materials for solar energy harvesting and management. Herein, after evaluating the energy band characteristics of 13 kinds of polyoxometalates (POMs), the trisubstituted POM compound K6H4[α-SiW9O37Co3(H2O)3]·17H2O (SiW9Co3) was first studied due to its relatively smaller band gap (2.23 eV) and higher lowest unoccupied molecular orbital (LUMO) level (−0.63 V vs NHE). Additionally, the preliminary computational modeling indicated that SiW9Co3 exhibited the donor–acceptor (D–A) structure, in which the cobalt oxygen clusters and tungsten skeletons act as the electron donor and electron acceptor, respectively. By employing SiW9Co3 to modify the TiO2 film, the visible photovoltaic and photocurrent response were both enhanced, and the light-induced photocurrent at 420 nm was improved by 7.1 times. Moreover, the highly dispersive and small sized SiW9Co3 nanoclusters loading on TiO2 were successfully achieved by fabricating the nanocomposite film of {TiO2/SiW9Co3}3 with the layer-by-layer method, which can result in the photovoltaic performance enhancement of dye-sensitized solar cells (DSSCs), of which the overall power conversion efficiency was improved by 25.6% from 6.79% to 8.53% through the synergistic effect of POMs and Ru-complex.Keywords: donor−acceptor; photovoltaic; polyoxometalate; TiO2; visible;
Co-reporter:Sha-Sha Xu, Wei-Lin Chen, Yan-Hua Wang, Yang-Guang Li, Zhu-Jun Liu, Chun-Hui Shan, Zhong-Min Su and En-Bo Wang
Dalton Transactions 2015 vol. 44(Issue 42) pp:18553-18562
Publication Date(Web):16 Sep 2015
DOI:10.1039/C5DT02992A
A di-vanadium-substituted Lindqvist-type polyoxometalate [Cu(C12H8N2)2]2[V2W4O19]·4H2O (1) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. X-ray photoelectron spectroscopy and energy disperse spectroscopy tests further prove the existence of vanadium. Ultraviolet photoelectron spectroscopy and density functional theoretical studies indicate that the energy level of 1 matches well with the conduction band of the TiO2. Furthermore, considering the semiconductor-like nature of 1 and the introduction of transition metal element Cu synchronously extends the absorption to the visible region, which should also be beneficial to the photovoltaic device performance. 1-Doped TiO2 composites (denoted as 1@TiO2) have been successfully fabricated by a simple sol–gel method, and introduced into the dye-sensitized solar cells (DSSCs) as co-sensitizers in N719-sensitized photoanodes by mixing 1@TiO2 with P25 nanoparticles with different weight ratios to enhance the photoelectric conversion efficiency. The investigations show that the DSSC assembled with 1@TiO2/19P25 photoanode has the best performance and the overall improvement of the efficiency is 21.6% compared with pure P25. Furthermore, the electrochemical impedance spectroscopy and open-circuit voltage decay investigations show that the cosensitization of 1 and N719 can promote electron transfer and restrain charge recombinations in the DSSCs, resulting in a longer electron lifetime.
Co-reporter:Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Rong-Lin Zhong, Ying Lu, Lan-Cui Zhang, Zhong-Min Su and En-Bo Wang
RSC Advances 2015 vol. 5(Issue 11) pp:8194-8198
Publication Date(Web):15 Dec 2014
DOI:10.1039/C4RA13005G
The photosensitive polyoxometalate (POM) [PW11O39RhCH2CO2H]5− was first introduced into the liquid crystal material through the encapsulation of dimethyldioctadecylammonium (DODA+). The theoretical calculation was performed to simulate the distribution of DODA+ around the POM anion. The surface photovoltage spectroscopy (SPS) result indicated that the hybrid exhibits the photovoltaic effect upon optical illumination and displays the character of a p-type material, which paves a new way for their potential application in the optoelectronics.
Co-reporter:Anqi Mu, Jiansheng Li, Weilin Chen, Xiaojing Sang, ZhongMin Su, Enbo Wang
Inorganic Chemistry Communications 2015 Volume 55() pp:149-152
Publication Date(Web):May 2015
DOI:10.1016/j.inoche.2015.03.032
•P2Mo18 was introduced into the supercapacitor electrode for the first time.•The AC/P2Mo18 composite material improves the specific capacitance of primitive AC.•An AC/P2Mo18 electrode exhibits a remarkable rate capability (89%).A supercapacitor electrode assembled from activated carbon (AC) and (NH4)6[P2Mo18O62]·14.2H2O (P2Mo18) was fabricated for the first time, and showed remarkable electrochemical performance ascribed to the synergy of the double layer capacitance of AC and the pseudocapacitance of P2Mo18. The investigations indicate that the AC/P2Mo18 electrode exhibits a specific capacitance of 275 F g− 1 at a high current density of 6 A g− 1, which is substantially larger than the 182 F g− 1 of the AC electrode. In addition, the AC/P2Mo18 electrode possesses a remarkable rate capability (89%) when the current density is increased from 2 to 6 A g− 1.An AC/P2Mo18 composite material exhibiting a higher specific capacitance (275 F g− 1) than an AC electrode (182 F g− 1) at a high current density of 6 A g− 1 and possessing a remarkable rate capability (89%) when the current density increased from 2 to 6 A g− 1 has been introduced into a supercapacitor electrode for the first time.
Co-reporter:Yuanhang Nie, Weilin Chen, Zhujun Liu, Enbo Wang
Inorganic Chemistry Communications 2015 Volume 61() pp:184-186
Publication Date(Web):November 2015
DOI:10.1016/j.inoche.2015.09.015
•We report three new complexes based on Keggin-typed POMs.•The complexes exhibit photocatalytic hydrogen evolution activities.•We firstly introduce the sacrificial electron donors into the structure POMs.A series of new complexes based on Keggin-type polyoxoanions (HTEA)2{[Na(TEA)2]H[SiW12O40]}∙5H2O (1), (HTEA)2{[Na(TEA)2][PW12O40]}∙4H2O (2) and (HTEA)2{[Na(TEA)2]H[GeW12O40]}∙4H2O (3) (TEA = triethanolamine) have been designed and synthesized. Single-crystal X-ray diffraction analyses reveal that compounds 1, 2 and 3 are isostructural, which exhibit the 1D chain structures consisting of Keggin-type polyoxoanions and {Na(TEA)2} linkers. Their structures were further characterized by XRD, IR spectroscopy, UV spectroscopy, elemental analyses, and thermogravimetric analysis. Moreover, compounds 1–3 present good the photocatalytic hydrogen evolution activities, which may be ascribed to the introduction of the sacrificial electron donors TEA to their structures, further, their photocatalytic hydrogen evolution activities are compared with its homologous Keggin-type heteropolyacid to verify the effect of TEA.The conventional photocatalytic system for hydrogen evolution requires both catalyst and sacrificial electron donor. Here, we firstly introduce the sacrificial electron donors into the structures of the POM anions and synthesize 3 new complexes. Their photocatalytic hydrogen evolution activities were compared with its homologous Keggin-type heteropolyacid, which demonstrate that the introduction of TEA can improve the photocatalytic activity.
Co-reporter:Zhongjie Huang;Wenjia Luo;Lu Ma;Mingzhe Yu;Xiaodi Ren;Mingfu He;Shane Polen;Kevin Click;Benjamin Garrett; Jun Lu; Khalil Amine; Christopher Hadad; Weilin Chen; Aravind Asthagiri; Yiying Wu
Angewandte Chemie 2015 Volume 127( Issue 50) pp:15396-15400
Publication Date(Web):
DOI:10.1002/ange.201507529
Abstract
Proton reduction is one of the most fundamental and important reactions in nature. MoS2 edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS2 edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo2S12]2−, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo2S12]2− is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo2S12]2− exhibits a hydrogen adsorption free energy near zero (−0.05 eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen-evolving enzymes.
Co-reporter:Zhongjie Huang;Wenjia Luo;Lu Ma;Mingzhe Yu;Xiaodi Ren;Mingfu He;Shane Polen;Kevin Click;Benjamin Garrett; Jun Lu; Khalil Amine; Christopher Hadad; Weilin Chen; Aravind Asthagiri; Yiying Wu
Angewandte Chemie International Edition 2015 Volume 54( Issue 50) pp:15181-15185
Publication Date(Web):
DOI:10.1002/anie.201507529
Abstract
Proton reduction is one of the most fundamental and important reactions in nature. MoS2 edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS2 edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo2S12]2−, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo2S12]2− is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo2S12]2− exhibits a hydrogen adsorption free energy near zero (−0.05 eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen-evolving enzymes.
Co-reporter:Xiaojing Sang, Jiansheng Li, Lancui Zhang, Zanjiao Wang, Weilin Chen, Zaiming Zhu, Zhongmin Su, and Enbo Wang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 10) pp:7876
Publication Date(Web):April 23, 2014
DOI:10.1021/am501192f
A novel sandwich-type germanotungstate [C(NH2)3]10[Mn2{Sn(CH2)2COOH}2(B-α-GeW9O34)2]·8H2O (1) represents the first single crystalline polyoxometalate (POM) functionalized by open chain carboxyethyltin, which was designed and synthesized in aqueous solution and applied to a dye-sensitized solar cell (DSSC) for the first time. Its photosensitivity was explored through a fluorescence spectrum (FL), surface photovoltage spectrum (SPV), electrochemical method, and solid diffuse spectrum. 1 displays the primary features of sensitizers in DSSCs, and the efficiency of the solar cell is 0.22%. Delightedly, when 1 was employed to assemble a cosensitized solar cell configuration by preparing a 1-doped TiO2 electrode and additionally adsorbing N719 dyes, a considerably improved efficiency was achieved through increasing spectral absorption and accelerating electron transport, which is 19.4% higher than that of single N719 sensitization. This result opens up a new way to position different dyes on a single TiO2 film for cosensitization.Keywords: carboxyethyltin; dye-sensitized solar cell; photosensitivity; polyoxometalate; TiO2;
Co-reporter:Xiao-Jing Sang, Jian-Sheng Li, Lan-Cui Zhang, Zai-Ming Zhu, Wei-Lin Chen, Yang-Guang Li, Zhong-Min Su and En-Bo Wang
Chemical Communications 2014 vol. 50(Issue 93) pp:14678-14681
Publication Date(Web):08 Oct 2014
DOI:10.1039/C4CC06211F
Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.29%) when used as counter electrodes in dye-sensitized solar cells.
Co-reporter:Chun-Chen Yuan, Shi-Ming Wang, Wei-Lin Chen, Lin Liu, Chao Qin, Zhong-Min Su and En-Bo Wang
Dalton Transactions 2014 vol. 43(Issue 4) pp:1493-1497
Publication Date(Web):12 Nov 2013
DOI:10.1039/C3DT52676C
Two Anderson-type heteropolyanion-supported copper phenanthroline redox couples have been successfully introduced into dye-sensitized solar cells, which can significantly increase the short-circuit photocurrent, open-circuit voltage and the conversion efficiency by 2.2 times, 26.8% and 3.93 times respectively, compared to the pristine copper phenanthroline redox couple.
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, Zhong-Min Su, En-Bo Wang, and Chao Li
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 1) pp:150-156
Publication Date(Web):2017-2-22
DOI:10.1021/ie402074c
A new H3PW12O40 (PW12)-based interfacial layer for dye-sensitized solar cells (DSSCs) has been fabricated by the LBL method. The features of the interfacial layer were tested by IR and UV–vis spectroscopies and AFM. The cells were systemically tested by the photocurrent–voltage (J–V) curve, dark-current measurement, open-circuit voltage decay (OCVD), and monochromatic incident photon-to-photocurrent conversion efficiency (IPCE) techniques. The PW12-based interfacial layer was found to accelerate electron transfer and retard recombination, eventually leading to an efficient increase in energy conversion efficiency. The investigations indicate that the energy conversion efficiency of a (PW12/TiO2)3-based DSSC is significantly enhanced by 54% at 100 mW cm–2 compared with a DSSC with no treatment and by 20% compared with a TiCl4-treatment DSSC. Polyoxometalate was first introduced into the interfacial layer in modifying the photoanode to accelerate electron transfer and retard recombination to improve DSSC efficiency in this work.
Co-reporter:Li Chen, Xiao-Jing Sang, Jian-Sheng Li, Chun-Hui Shan, Wei-Lin Chen, Zhong-Min Su, En-Bo Wang
Inorganic Chemistry Communications 2014 Volume 47() pp:138-143
Publication Date(Web):September 2014
DOI:10.1016/j.inoche.2014.07.019
•{P2Mo18VI} and {P2Mo2VMo16VI} were first introduced into photoanode of DSSCs.•Both heteropolyacid and heteropoly blue can improve the performance of DSSCs.•{P2Mo18VI} and {P2Mo2VMo16VI} could both suppress the dark current in DSSCs.•{P2Mo18VI} and {P2Mo2VMo16VI} could both increase the electron lifetime in DSSCs.•Heteropoly blue can be a potential electron attractor for photovoltaic application.Dawson-type heteropolyacid {P2Mo18VI} and its two-electron heteropoly blue {P2Mo2VMo16VI}-doped TiO2 composites have been successfully prepared by a simple sol–gel method and introduced into the photoanode of dye-sensitized solar cells (DSSCs), which results in a significant performance enhancement of DSSCs. The electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD) curve were employed to investigate the electron transport and carrier recombination behavior in DSSCs. The results show that doping with {P2Mo18VI} and {P2Mo2VMo16VI} could both suppress the dark current and increase the electron lifetime in DSSCs. The performance of DSSCs with both {P2Mo18VI}-doped and {P2Mo2VMo16VI}-doped photoanodes is better than that with pure P25 photoanodes and the overall conversion efficiency was improved by 24.48% and 17.19%, respectively.Dawson-type heteropolyacid {P2Mo18VI} and its two-electron heteropoly blue {P2Mo2VMo16VI}-doped TiO2 composites have been introduced into the photoanode of DSSCs for the first time, which could both suppress the dark current and increase the electron lifetime in DSSCs.
Co-reporter:Chun-Chen Yuan, Shi-Ming Wang, Wei-Lin Chen, Lin Liu, Zhi-Ming Zhang, Ying Lu, Zhong-Min Su, Si-Wen Zhang, En-Bo Wang
Inorganic Chemistry Communications 2014 Volume 46() pp:89-93
Publication Date(Web):August 2014
DOI:10.1016/j.inoche.2014.05.023
•This is the first report of a pure-inorganic-cobalt-compound redox couple for DSSCs.•Two Keggin-type POMs have been employed as a redox couple in DSSCs.•The redox potential of the {CoII/IIIW12} couple matches with dye and TiO2.•The {CoII/IIIW12} redox couple shows weak absorption in the visible light region.Two Keggin-type polyoxometalates [K6CoIIW12O40 (denoted as {CoIIW12}) and K5CoIIIW12O40 (denoted as {CoIIIW12})] were firstly employed as the redox couple in dye-sensitized solar cells. Photocurrent density–photovoltage curves, cyclic voltammetry curves, photocurrent action spectra and UV–vis spectra demonstrated that {CoIIW12} and {CoIIIW12} displayed weak absorption in the visible light region, potential matching with dye and TiO2 conducting band, and significant conversion efficiency.Two Keggin-type polyoxometalates have been successfully employed as the redox couple in dye-sensitized solar cells for the first time, which achieved relatively high values of open circuit voltage (651 mV) and fill factor (0.549).
Co-reporter:Chun-Hui Shan, Xiao-Jing Sang, Hong Zhang, Jian-Sheng Li, Wei-Lin Chen, Zhong-Min Su, En-Bo Wang
Inorganic Chemistry Communications 2014 50() pp: 13-16
Publication Date(Web):
DOI:10.1016/j.inoche.2014.10.004
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, Zhi-Ming Zhang, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 2) pp:216-220
Publication Date(Web):15 Nov 2012
DOI:10.1039/C2TA00486K
We explore a new method to prepare polyoxometalate-based electrochromic (EC) smart windows. It is a simple and low cost process to prepare EC films by a solution-based electrodeposition method. The polyoxometalate-based EC smart windows exhibit high transparency in the bleached state, good optical contrast, long durability, and high coloration efficiency.
Co-reporter:Ge Jin, Shi-Ming Wang, Wei-Lin Chen, Chao Qin, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 23) pp:6727-6730
Publication Date(Web):26 Apr 2013
DOI:10.1039/C3TA10814G
A spherical keplerate {W72V30} acts as the electron acceptor in a photovoltaic system for the first time. It is a promising alternative electron acceptor to the traditional electron acceptor fullerene (C60). A water-soluble PPV derivative (P2) was chosen as the electron donor. This work represents a promising strategy in designing polymer photovoltaic devices.
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, En-Bo Wang
Electrochimica Acta 2013 Volume 113() pp:240-247
Publication Date(Web):15 December 2013
DOI:10.1016/j.electacta.2013.09.048
•Polyoxometalates-based smart windows have been fabricated using electrodeposition method.•The slight adjusting of the structure of the polyoxometalates influences electrochromic properties of the smart windows greatly.•The electrochromic smart windows show high performance in both visible and near-infrared region.•The maximum optical contrast of 93.1% achieved under low applied potential.Polyoxometalates (POMs) are a kind of metal oxide nanoclusters with excellent electrical properties, which have proved to be an excellent candidate for electrochromism (EC) materials. In this paper, we present a better performance POMs-based EC material on the TiO2 substrate through adjusting the structure of the Well-Dawson type POMs with the electrodeposition method, which can overcome the high cost of the traditional methods such as vacuum evaporation or sputtering. The performance of the EC smart windows was fully tested. The maximum optical contrast for the K10[P2W17O61]·20H2O (P2W17)-based EC smart window is 93.1% at the wavelength of 620 nm and for the K6[P2W18O62]·14H2O (P2W18)-based EC smart window is 48.7% at 646 nm. The coloration time extracted for a 90% transmittance for the P2W17-based EC smart window is 0.9 s and for the P2W18-based smart window is 0.97 s; the coloration efficiency for the P2W17-based EC smart window is 205.3 cm2 C−1 and the P2W18-based smart window is 176.8 cm2 C−1. Both of the P2W17- and P2W18-based EC smart windows have the feature of remarkable durability over 1000 cycles. The P2W17-based smart window has larger optical contrast and higher coloration efficiency than the P2W18-based smart window. More significantly, the near-infrared behavior of the P2W17 under different applied potentials was recorded for the first time by using the smart window. We believe the performance of the P2W17-based smart window is the state-of-the-art among the POMs-based EC smart windows.High performance polyoxometalates (POMs)-based electrochromic smart windows have been fabricated. By adjusting the structure of the Dawson-type POM, it can be found that mono-vacant lacunary Dawson-type POM-based smart window has remarkable performance. For example, the maximum optical contrast 93.1% at the wavelength of 620 nm; the coloration time extracted for a 90% transmittance is 0.90 s; and the coloration efficiency is 205.3 cm2 C−1. The near-infrared electrochromic behaviors of the POMs have been investigated for the first time.
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, En-Bo Wang and Zhong-Min Su
Dalton Transactions 2013 vol. 42(Issue 8) pp:2691-2695
Publication Date(Web):11 Dec 2012
DOI:10.1039/C2DT32403B
Polyoxometalate–TiO2 composites have been successfully introduced into the photoanode of dye-sensitized solar cells to reduce the recombination of the electrons, which results in a longer electron lifetime. The performance of the cells with the polyoxometalate-modified photoanode is better than the cell with a pure P25 photoanode. The effect of the polyoxometalate was studied by electrochemical impedance spectroscopy and open-circuit voltage decay measurement. The results show that the electron lifetime becomes longer following an increase in the amount of the polyoxometalate.
Co-reporter:Jiansheng Li;Xiaojing Sang;Weilin Chen;Chao Qin;Shiming Wang;Zhongmin Su ;Enbo Wang
European Journal of Inorganic Chemistry 2013 Volume 2013( Issue 10-11) pp:1951-1959
Publication Date(Web):
DOI:10.1002/ejic.201201120
Abstract
ZnO nanoparticles (NPs) containing H3PW12O40 polyoxometalates (POMs) were firstly synthesized by a simple solvothermal route. The photoanodes of dye-sensitized solar cells (DSSCs) were assembled with the as-prepared ZnO powder containing H3PW12O40. A comparative experiment in the absence of POMs was carried out to investigate the influence of H3PW12O40. Furthermore, the effects of other Keggin-type POMs including W series, Mo series, and the potassium salt K3PW12O40 were studied and different concentrations of H3PW12O40 were utilized to investigate the impact on the performance of DSSCs on the basis of the above research. The results demonstrate that the W-containing POM series HxMW12O40 (M = P, x = 3; M = Si, Ge, x = 4) significantly enhances the performance of DSSCs by increasing electronic lifetimes and reducing dark currents. The overall solar-to-electric energy conversion efficiency reached a maximum of 2.70 % in the presence of H3PW12O40, which is an improvement of 49.2 % compared to the efficiency without H3PW12O40. A suitable H3PW12O40 concentration is crucial.
Co-reporter:Chunchen Yuan, Shuangshuang Guo, Shiming Wang, Lin Liu, Weilin Chen, and Enbo Wang
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 20) pp:6694-6703
Publication Date(Web):April 25, 2013
DOI:10.1021/ie302845z
A polyoxometalate (POM)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) hybrid film counter electrode was successfully fabricated by electropolymerization in an environmentally friendly aqueous solution. The hybrid film presents a similar surface morphology to lotus leaf, the microstructure of which is a regularly distribution of mastoid shapes. As far as we know, it is the first time that POM-PEDOT hybrid film with mastoid morphology was fabricated. The application of the hybrid film counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) was studied for the first time, and the efficiency of DSSCs based on hybrid film CEs was almost as high as DSSCs with Pt CEs. FTIR results indicated that POM polyanions had already been dispersed into the PEDOT matrix. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization test results show that the electrocatalytic ability for I3– reduction of the hybrid film CE is comparable to that of a Pt CE. In addition, the SiW11–PEDOT hybrid film has good electrochemical stability.
Co-reporter:Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Lan-Cui Zhang, Zhong-Min Su, Chao Qin, En-Bo Wang
Inorganic Chemistry Communications 2013 Volume 38() pp:78-82
Publication Date(Web):December 2013
DOI:10.1016/j.inoche.2013.10.027
•The polyoxometalates (POMs) sensitized solar cell (PSSC) was studied firstly.•It is breakthrough to put forward that POMs export electrons under irradiation.•The energy level and band gap were investigated for the POMs base sensitizer.Keggin-type polyoxometalates (POMs) based photosensitizer [(CH3)4N]5[PW11O39RhCH2COOH]∙6H2O (PW11Rh-COOH) was firstly explored for assembling the POMs sensitized solar cells (PSSC). Electrochemical measurement, UV–vis diffuse reflectance spectrum, Surface photovoltage spectrum, and X-ray photoelectron spectroscopy demonstrated that PW11Rh-COOH displayed higher photovoltaic response than that of other POMs because of the better visible-light response, energy level matching and higher carrier separation efficiency.Keggin-type polyoxometalates (POMs) based photosensitizer [(CH3)4N]5[PW11O39RhCH2COOH]∙6H2O (PW11Rh-COOH) was firstly explored for assembling the POMs sensitized solar cells (PSSC), which displayed higher photovoltaic response than that of other POMs because of the better visible-light response, energy level matching and higher carrier separation efficiency.
Co-reporter:Jun Zhang, Wei-Lin Chen, En-Bo Wang
Inorganic Chemistry Communications 2013 Volume 38() pp:96-99
Publication Date(Web):December 2013
DOI:10.1016/j.inoche.2013.10.010
•For the first time, D–π–A type POMs were combined with TiO2;•The composite materials were synthesized through layer-by-layer method.•The POM@TiO2 showed excellent catalytic ability in treating organic pollutants.Donor–π-bridge–acceptor (D–π–A) type polyoxometalates (POMs) were self-assembled for the first time on the surface of titanium dioxide (TiO2) nanoparticles through the layer-by-layer (LBL) method. The obtained composite materials POM@TiO2 were characterized by Transmission electron microscopy (TEM), Fourier transform IR spectroscopy (FTIR), Raman spectrum and energy dispersive X-ray (EDX) spectroscopy. Catalytic properties of POM@TiO2 were also investigated by treating organic pollutants (typically, removal of 40 mL 20 mg L− 1 methylene blue (MB) by 10 mg POM@TiO2 was up to 99.5% within 3 min under ambient conditions and the photodegradation efficiency was obviously higher than bare TiO2 nanoparticles under irradiation).Novel composite materials based on D–π–A type polyoxometalates and TiO2 with excellent catalytic ability in treating organic pollutants
Co-reporter:Zhen-Li Wang, Hua-Qiao Tan, Wei-Lin Chen, Yang-Guang Li and En-Bo Wang
Dalton Transactions 2012 vol. 41(Issue 33) pp:9882-9884
Publication Date(Web):22 Jun 2012
DOI:10.1039/C2DT30663H
A new dimer polyoxoniobate [Cu(en)2]11K4Na2[KNb24O72H9]2·120H2O (1) has been synthesized and systematically characterized. Visible light photocatalytic H2 evolution activity was researched with 1 as the visible-light photosensitizer and catalyst, cobaloximes [CoIII(dmgH)2pyCl] as the co-catalysts, and triethylamine (TEA) as the sacrificial electron donor.
Co-reporter:Xiaojing Sang, Jiansheng Li, Weilin Chen, Enbo Wang
Materials Letters 2012 Volume 87() pp:39-42
Publication Date(Web):15 November 2012
DOI:10.1016/j.matlet.2012.07.100
With the assistance of polyoxometalates (POM), ZnO polyhedra with the mean length of 200 nm and mean diameter of 100 nm are synthesized by a simple solvothermal route in an alkali solution. Parallel experiments without POM were carried out to investigate the formation process of ZnO polyhedra and the results showed that POM played a key role in the formation of ZnO polyhedra. A possible formation mechanism was also proposed. Meanwhile, the as-prepared ZnO powder was used to assemble dye-sensitized solar cells (DSSC) photoanodes, the overall solar-to-electric energy conversion efficiency was up to 2.45%, which were obtained using TiCl4 post-treatment.Graphical abstractZnO polyhedrons were synthesized by a simple solvothermal route with the assistance of K7HNb6O19. ZnO nanoclusters generated at the beginning of the reaction. POMs adsorb on the surface of the nanoclusters, inhibiting their further growth into nanorods and facilitating them gather into the relatively stable polyhedral structure.Highlights► ZnO polyhedra were synthesized with the assistance of isopolyoxometalates. ► K7HNb6O19 was first introduced into the preparation of ZnO. ► A possible formation mechanism was proposed. ► Polyoxometalate-assisted synthesized ZnO was first introduced into the field of DSSC. ► Conversion efficiency was significantly improved by TiCl4 post-treatment.
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, En-Bo Wang and Zhong-Min Su
Dalton Transactions 2013 - vol. 42(Issue 8) pp:NaN2695-2695
Publication Date(Web):2012/12/11
DOI:10.1039/C2DT32403B
Polyoxometalate–TiO2 composites have been successfully introduced into the photoanode of dye-sensitized solar cells to reduce the recombination of the electrons, which results in a longer electron lifetime. The performance of the cells with the polyoxometalate-modified photoanode is better than the cell with a pure P25 photoanode. The effect of the polyoxometalate was studied by electrochemical impedance spectroscopy and open-circuit voltage decay measurement. The results show that the electron lifetime becomes longer following an increase in the amount of the polyoxometalate.
Co-reporter:Sha-Sha Xu, Wei-Lin Chen, Yan-Hua Wang, Yang-Guang Li, Zhu-Jun Liu, Chun-Hui Shan, Zhong-Min Su and En-Bo Wang
Dalton Transactions 2015 - vol. 44(Issue 42) pp:NaN18562-18562
Publication Date(Web):2015/09/16
DOI:10.1039/C5DT02992A
A di-vanadium-substituted Lindqvist-type polyoxometalate [Cu(C12H8N2)2]2[V2W4O19]·4H2O (1) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. X-ray photoelectron spectroscopy and energy disperse spectroscopy tests further prove the existence of vanadium. Ultraviolet photoelectron spectroscopy and density functional theoretical studies indicate that the energy level of 1 matches well with the conduction band of the TiO2. Furthermore, considering the semiconductor-like nature of 1 and the introduction of transition metal element Cu synchronously extends the absorption to the visible region, which should also be beneficial to the photovoltaic device performance. 1-Doped TiO2 composites (denoted as 1@TiO2) have been successfully fabricated by a simple sol–gel method, and introduced into the dye-sensitized solar cells (DSSCs) as co-sensitizers in N719-sensitized photoanodes by mixing 1@TiO2 with P25 nanoparticles with different weight ratios to enhance the photoelectric conversion efficiency. The investigations show that the DSSC assembled with 1@TiO2/19P25 photoanode has the best performance and the overall improvement of the efficiency is 21.6% compared with pure P25. Furthermore, the electrochemical impedance spectroscopy and open-circuit voltage decay investigations show that the cosensitization of 1 and N719 can promote electron transfer and restrain charge recombinations in the DSSCs, resulting in a longer electron lifetime.
Co-reporter:Zhen-Li Wang, Hua-Qiao Tan, Wei-Lin Chen, Yang-Guang Li and En-Bo Wang
Dalton Transactions 2012 - vol. 41(Issue 33) pp:NaN9884-9884
Publication Date(Web):2012/06/22
DOI:10.1039/C2DT30663H
A new dimer polyoxoniobate [Cu(en)2]11K4Na2[KNb24O72H9]2·120H2O (1) has been synthesized and systematically characterized. Visible light photocatalytic H2 evolution activity was researched with 1 as the visible-light photosensitizer and catalyst, cobaloximes [CoIII(dmgH)2pyCl] as the co-catalysts, and triethylamine (TEA) as the sacrificial electron donor.
Co-reporter:Xiao-Jing Sang, Jian-Sheng Li, Lan-Cui Zhang, Zai-Ming Zhu, Wei-Lin Chen, Yang-Guang Li, Zhong-Min Su and En-Bo Wang
Chemical Communications 2014 - vol. 50(Issue 93) pp:NaN14681-14681
Publication Date(Web):2014/10/08
DOI:10.1039/C4CC06211F
Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.29%) when used as counter electrodes in dye-sensitized solar cells.
Co-reporter:Ge Jin, Shi-Ming Wang, Wei-Lin Chen, Chao Qin, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 23) pp:NaN6730-6730
Publication Date(Web):2013/04/26
DOI:10.1039/C3TA10814G
A spherical keplerate {W72V30} acts as the electron acceptor in a photovoltaic system for the first time. It is a promising alternative electron acceptor to the traditional electron acceptor fullerene (C60). A water-soluble PPV derivative (P2) was chosen as the electron donor. This work represents a promising strategy in designing polymer photovoltaic devices.
Co-reporter:Dan Xu, Wei-Lin Chen, Jian-Sheng Li, Xiao-Jing Sang, Ying Lu, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 19) pp:NaN10178-10178
Publication Date(Web):2015/03/31
DOI:10.1039/C5TA01578B
SiW11V/graphene nanocomposite was first prepared and introduced into TiO2 film. It showed a significant photocurrent response, which can be attributed to the photoinduced electrons of SiW11V. This work provides a promising strategy for exploring POMs sensitizers with lower energy levels than the CB of TiO2.
Co-reporter:Shi-Ming Wang, Lin Liu, Wei-Lin Chen, Zhi-Ming Zhang, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 2) pp:NaN220-220
Publication Date(Web):2012/11/15
DOI:10.1039/C2TA00486K
We explore a new method to prepare polyoxometalate-based electrochromic (EC) smart windows. It is a simple and low cost process to prepare EC films by a solution-based electrodeposition method. The polyoxometalate-based EC smart windows exhibit high transparency in the bleached state, good optical contrast, long durability, and high coloration efficiency.
Co-reporter:Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Lan-Cui Zhang, Zai-Ming Zhu, Yang-Guang Li, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 28) pp:NaN14577-14577
Publication Date(Web):2015/06/12
DOI:10.1039/C5TA03259H
A strategy was developed for the first time to fabricate highly dispersed and small-sized polyoxometalate nanoparticles loaded on a TiO2 film by using MIL-101 to prevent agglomeration, and calcination to break the metal–organic framework, which can result in performance improvement of quantum dot solar cells.
Co-reporter:Chun-Chen Yuan, Shi-Ming Wang, Wei-Lin Chen, Lin Liu, Chao Qin, Zhong-Min Su and En-Bo Wang
Dalton Transactions 2014 - vol. 43(Issue 4) pp:NaN1497-1497
Publication Date(Web):2013/11/12
DOI:10.1039/C3DT52676C
Two Anderson-type heteropolyanion-supported copper phenanthroline redox couples have been successfully introduced into dye-sensitized solar cells, which can significantly increase the short-circuit photocurrent, open-circuit voltage and the conversion efficiency by 2.2 times, 26.8% and 3.93 times respectively, compared to the pristine copper phenanthroline redox couple.
Co-reporter:Li Chen, Weilin Chen, Huaqiao Tan, Jiansheng Li, Xiaojing Sang and Enbo Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 11) pp:NaN4133-4133
Publication Date(Web):2016/02/10
DOI:10.1039/C5TA10260J
Quantum dot sensitized solar cells with high theoretical conversion efficiency, low production cost and a simple production process have received great attention in recent years. For CdSe-sensitized cells, the most significant defect of CdSe is that it has the weak absorption between 550 and 600 nm and no absorption after 650 nm, so it is crucial to find a wide spectrum photosensitizer to make up for the defect. Here, wide spectrum and pure inorganic Donor–Acceptor (D–A) Type Polyoxometalate (POM) K6H4[α-SiW9O37Co3(H2O)3]·17H2O (denoted as T) is firstly introduced into QDSCs as a collaborative cosensitizer with CdSe. The T has a visible characteristic peak centering between 550 and 600 nm, and also has stronger absorption after 650 nm, which could make up for the defect of CdSe to constitute a wide spectrum of absorption. The fluorescence spectrum, surface photovoltage spectrum, ultraviolet photoelectron spectroscopy spectrum and solid diffuse spectrum were used to explore the photosensitivity of T. In addition, the D–A type POM can act as a good intermediate for the injection of electrons and improve the visible photocurrent response; meanwhile, it can obviously reduce the dark current and increase the electron lifetime, which can solve the problem about the high recombination at the QD/TiO2/electrolyte interface. In general, the best photovoltaic performance of T and CdSe cosensitized solar cells is increased to 6.59% (Jsc = 18.37 mA cm−2, Voc = 0.57 V, FF = 0.63), which is improved by 32.33% compared to those of the pure CdSe-sensitized cells (Jsc = 16.20 mA cm−2, Voc = 0.50 V, FF = 0.61, η = 4.98%).
Co-reporter:Yi-Jing Wang, Wei-Lin Chen, Li Chen, Xiao-Tao Zheng, Sha-Sha Xu and En-Bo Wang
Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 3) pp:NaN565-565
Publication Date(Web):2017/01/17
DOI:10.1039/C6QI00570E
Sandwich-type polyoxometalates K6Na2Ni2[Ni4(H2O)2(SiW9O34)2]·30H2O(Ni4), K6Na2Co2[Co4(H2O)2(SiW9O34)2]·30H2O(Co4) and K10[Ni(H2O)2(γ-SiW10O35)2]·13.25H2O(Ni1) were doped into TiO2 separately and applied as photoanodes for dye-sensitized solar cells (DSSCs) for the first time, enhancing the current intensity and photoelectric conversion efficiency of the cells. The TiO2 and POM@TiO2 used in this paper were synthesized by a modified sol–gel method. The Jsc of pure P25 is 15.84 mA cm−2, the Voc is 0.637 V, the FF is 0.564, and the η is 5.69%. The Jsc of the prepared TiO2 is 16.48 mA cm−2, the Voc is 0.68 V, the FF is 0.537 and the η is 6.01%, which is a higher efficiency than that of pure P25, therefore the POMs@TiO2 were directly used in photoanodes without being formed into composites with P25 in this paper. The Jsc of 0.8% Ni4@TiO2 is 18.79 mA cm−2, the Voc is 0.71 V, the FF is 0.595 and the η is 7.94%, which is 32.1% higher than that of the prepared TiO2 based DSSC. 0.8% Co4@TiO2 and 0.8% Ni1@TiO2 modified photoanodes obtained power conversion efficiencies of 6.22% and 6.17%. The electron lifetimes of the self-prepared TiO2 and 0.8% Ni4@TiO2 are 13.5 ms and 28 ms respectively, calculated from a bode plot. Among the three kinds of sandwich-type POMs mentioned in this paper, the 0.8% Ni4 modified photoanode in DSSCs exhibited the best performance in enhancing light harvesting and reducing electron recombination. The energy levels of Ni4 were also investigated.
Co-reporter:Chun-Hui Shan, Hong Zhang, Wei-Lin Chen, Zhong-Min Su and En-Bo Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 9) pp:NaN3303-3303
Publication Date(Web):2016/01/22
DOI:10.1039/C5TA10601J
A pure inorganic donor–acceptor (D–A) type polyoxometalate K6H4[α-SiW9O37Co3(H2O)3]·17H2O (SiW9Co3)/reduced graphene oxide (RGO) nanocomposite was employed to dye-sensitized solar cells (DSSCs) for the first time, building up a wide spectrum for the photoanode of a DSSC. Raman, XRD, TEM, and EDS have proved that SiW9Co3 was loaded on RGO, and then the SiW9Co3/RGO doped nanocomposite in P25 was applied to be the photoanode of the DSSCs. In this paper the performance of SiW9Co3/RGO-3@P25 is the best. The Jsc of pure P25 is 13.74 mA cm−2, Voc is 0.679 V, FF is 0.598 and η is 5.37%, while the Jsc of SiW9Co3/RGO-3@P25 is 17.5 mA cm−2, Voc is 0.705 V, FF is 0.558 and η is enhanced to 6.88%, which is 28.05% higher than for a pure P25-based cell in a DSSC. OCVD indicates that SiW9Co3/RGO can delay the electron–hole recombination. In a Bode plot the electron lifetimes of SiW9Co3/RGO-3@P25 and P25 are 4.86 ms and 3.81 ms respectively, which also further clarifies that the SiW9Co3/RGO doped nanocomposite can extend the lifetime of electrons and also plays an important role in the photoanode of the DSSCs. This result is beneficial to the application of DSSCs in future industry.
Co-reporter:Xiang-Wei Guo, Xiao-Hong Li, Zhu-Jun Liu, Wei-Lin Chen, Xiao-Tao Zheng, En-Bo Wang and Zhong-Min Su
Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 7) pp:NaN1191-1191
Publication Date(Web):2017/05/08
DOI:10.1039/C7QI00160F
Photosensitizers play a crucial role in p-type dye-sensitized solar cells (p-DSSCs). In this study, we first introduced two Dawson-type transition metal-substituted polyoxometalate dyes to co-sensitize the NiO electrode and achieved an overall power conversion efficiency (PCE) of 0.0464%, which is the highest value reported for inorganic photosensitizers in p-DSSCs.
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