Co-reporter:Kai Yao, Xiaofeng Wang, Yun-xiang Xu, Fan Li, and Lang Zhou
Chemistry of Materials 2016 Volume 28(Issue 9) pp:3131
Publication Date(Web):April 12, 2016
DOI:10.1021/acs.chemmater.6b00711
Despite the dramatic rise in power conversion efficiencies (PCEs) of perovskite solar cells (PeSCs), concerns surrounding the long-term stability as well as the poor reproducibility in the archetypal three-dimensional (3D) perovskite, MAPbI3 (MA = CH3NH3), have the potential to derail commercialization. We have reported the fabrication and properties of a series of 2D perovskite compounds (PEI)2(MA)n−1PbnI3n+1 (n = 3, 5, 7) by incorporating polyethylenimine (PEI) cations within the layered structure. The benefits of using intercalated polymer cations in the multilayered films are multiple: moisture resistance and film quality are greatly enhanced compared to that of their 3D MAPbI3 analogue; charge transport within solar cells can also be improved compared to that of 2D materials using small-molecule bulky ammonium. The moisture-stable nature of the multilayered perovskite materials allow for the simple one-step fabrication of cells with an aperture area of 2.32 cm2 under ambient humidity that have a PCE up to 8.77%. Overall, the 2D perovskite family offers rich multitudes of substituent and crystal structures, defining a promising class of stable and efficient light-absorbing materials.
Co-reporter:Zhenrong Jia, Ying Wei, Xiaofeng Wang, Siwei Hu, Kai Yao, Fan Li
Chemical Physics Letters 2016 Volume 661() pp:119-124
Publication Date(Web):16 September 2016
DOI:10.1016/j.cplett.2016.08.062
Highlights
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The DPP-TP6 liquid crystal molecules are introduced in P3HT/ZnO hybrid systems.
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Induced by DPP-TP6 liquid crystal molecule, morphology of P3HT/ZnO is improved.
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Benefiting from the improvement in morphology of P3HT/ZnO, the PCE is improved.
Co-reporter:Jingni Wang, Kai Yao, Zhenrong Jia, Xiaofeng Wang, Fan Li
Superlattices and Microstructures 2016 Volume 97() pp:378-385
Publication Date(Web):September 2016
DOI:10.1016/j.spmi.2016.06.041
Microstructure control is critical to achieve thin film-based devices with high performance. The surface properties of the substrates on which thin films grow are expected to greatly influence the morphology and the resulting performance. Generally, homogeneous, dense and highly crystalline films are required. However, “island” like structures are usually obtained mainly due to the non-uniform nucleation. In this article, the self-assembling monolayer (SAM) strategy was applied to efficiently realize the uniform nucleation and modulate the microstructure of lead sulfide (PbS) thin films, which were fabricated on the modified ZnO-coated substrates with 3-mercaptopropionic acid (MPA) SAM via in-situ thermal decomposition of lead xanthate precursors. The results showed that PbS thin films with reduced pin-holes and uniform crystalline grains were fabricated with the incorporation of MPA SAM. More importantly, PbS thin films modulated by MPA showed better photoelectric response.Improved microstructure and photocurrent response of the PbS thin films fabricated by in-situ thermal decomposition of lead xanthate precursors via the introduction of self-assembling monolayers of 3-mercaptopropionic acid between PbS and ZnO-coated glass/ITO substrates.
Co-reporter:Kai Yao, Xiaofeng Wang, Fan Li and Lang Zhou
Chemical Communications 2015 vol. 51(Issue 84) pp:15430-15433
Publication Date(Web):26 Aug 2015
DOI:10.1039/C5CC05879A
We have described the compositional engineering of mixed perovskite based on methyl- and polymeric-ammonium. The resulting perovskite films containing moisture-resistant 2D materials exhibit a maximum power conversion efficiency of over 15% with high reproducibility and good stability, offering greater tunability at the molecular level for material optimization.
Co-reporter:Xiaofeng Wang, Siwei Hu, Qiujuan Li, Fan Li, Kao Yao and Meiying Shi
RSC Advances 2015 vol. 5(Issue 65) pp:52874-52881
Publication Date(Web):09 Jun 2015
DOI:10.1039/C5RA07362F
A type of ionic liquid crystals, 4′-(N,N,N-trimethyl ammonium bromide hexyloxy)-4-cyanobiphenyl (6CNBP-N), was synthesized and explored as a novel additive to modify the PEDOT:PSS anode buffer layer for P3HT:PCBM polymer solar cells (PSCs). Due to the ionic functions of 6CNBP-N, the amount of PEDOT on top surface of PEDOT:PSS was increased with increasing amount of 6CNBP-N, leading to a rougher surface and better conductivity. Most strikingly, when the 6CNBP-N modified PEDOT:PSS anode buffer layer was annealed at 150 °C (in the mesophase temperature region of 6CNBP-N), a more continuous network in the modified PEDOT:PSS film and more ordered microstructure and higher crystallization of P3HT in the overlying P3HT:PCBM active layer were formed, mainly induced by the self-assembling behavior of 6CNBP-N in its mesomorphism, thus favoring excition dissociation, charge transport and collection. Without undergoing the annealing of active layers, the power conversion efficiency (PCE) of 3.17% was obtained. Our results showed that the ionic liquid crystals, which combined the liquid crystal properties and ionic functions, were a promising additive for PEDOT:PSS, which could improve the properties of the PEDOT:PSS buffer layer and the overlying active layer at the same time, thereby enhancing the PCE of PSCs.
Co-reporter:Kai Yao, Xiaofeng Wang, Yun-xiang Xu, Fan Li
Nano Energy 2015 Volume 18() pp:165-175
Publication Date(Web):November 2015
DOI:10.1016/j.nanoen.2015.10.010
•In-situ-generated layered perovskite derived from polymeric ammonium were designed as a general fabrication method for controlling over the morphology to produce stable and reproducible perovskite solar cells with power conversion efficiency of 13.8% on flexible substrates in ambient air.•Our design of novel two-dimensional materials affords a facile way with great tunability in perovskite families for photovoltaic applications.Compared to the 3D lead-halide perovskites (MAPbX3, X=I/Cl), two dimensional (2D) perovskites have more flexible structures, with more relaxed limitations in the size of the organic cations and produce interesting variant of photophysical and electronic properties. Here, a universal deposition approach for stable and efficient MAPbX3 perovskite solar cells (PeSCs) displaying excellent reproducibility are presented via in-situ formed layered perovskites derived from polymeric ammonium anchor. The critical effect of in-situ formed layered perovskite (PEI)2[PbI4] on the morphological and interfacial control of the above 3D perovskite are identified, and it is demonstrated that 2D perovskite films promote the formation of above perovskite films composed of micron-sized grains and provide better energy level alignment at the interface. Moreover, the incorporation of great moisture-resistant 2D materials, accompanying uniform and dense MAPbX3 films enhances long-term stability of the perovskite solar cells. As a result, a maximum PCE value of 13.8% for MAPbI3 solar cells on flexible substrate are achieved in ambient air. It is anticipated that our strategies to design and explore low dimensional perovskites can provide alternative route to address the critical concerns of stability and reproducibility in PeSCs.In-situ-generated layered perovskite derived from polymeric ammonium were designed as a general fabrication method for controlling over the morphology to produce stable and reproducible perovskite solar cells with power conversion efficiency of 13.8% on flexible substrates in ambient air. Our design of novel two-dimensional materials affords a facile way with great tunability in perovskite families for photovoltaic applications.
Co-reporter:Yueqin Shi, Fan Li and Yiwang Chen
New Journal of Chemistry 2013 vol. 37(Issue 1) pp:236-244
Publication Date(Web):19 Oct 2012
DOI:10.1039/C2NJ40779E
The well-defined rod–coil diblock copolymer poly(3-hexylthiophene)-b-poly(ethylene oxide) (P3HT-b-PEO) was used as the interfacial compatibilizer for P3HT/ZnO (1:2 w/w) hybrid heterojunction solar cells. The power conversion efficiency of the device was enhanced from 0.5 to 0.98% in the presence of 0–10 wt% P3HT-b-PEO under illumination of AM 1.5G (100 mW cm−2), resulting from the morphology variation. In the P3HT/ZnO/P3HT-b-PEO ternary blends, the block copolymer does not influence the crystallinity of ZnO NPs, but does influence the crystallinity of P3HT and the dispersion of ZnO NPs. An enhanced crystalline and fiber-like P3HT and more uniform dispersion of ZnO NPs are observed with a small amount of P3HT-b-PEO (10 wt%) loading, leading to a smaller domain size, enhanced interfacial area for charge separation and a favored active layer morphology for improving the device performance. On the other hand, the incorporated P3HT-b-PEO could also suppress macrophase separation during long time thermal annealing and improve the device thermal stability. These results demonstrated that the promising effect of the rod–coil diblock copolymers interfacial compatibilizer for controlling the morphology and improving the performance of hybrid bulk heterojunction solar cells.
Co-reporter:Fan Li, Qiujuan Li, Yiwang Chen
Journal of Luminescence 2012 Volume 132(Issue 8) pp:2114-2121
Publication Date(Web):August 2012
DOI:10.1016/j.jlumin.2012.03.071
Here we report the fabrication of a novel nano-level hybrid of ZnO nanoparticles (NPs) and liquid crystals (LCs) by the attachment of organic LC molecules with a mercapto moiety, namely, 4′-n-(6-mercaptohexyloxy)-4-cyanobiphenyl (6CNBP-SH), to the surface of ZnO nanoparticles. The dispersion of modified ZnO NPs (6CNBP-SH@ZnO) is greatly improved by the surface modification of 6CNBP-SH ligands. The photoluminescence (PL) measurement shows that the ultra-violet emission of ZnO can be enhanced by the surface modification of 6CNBP-SH ligands and annealing at liquid crystal state temperature of 6CNBP-SH@ZnO (110 °C). Meanwhile, defect-related emission of ZnO in 6CNBP-SH@ZnO almost disappears. We attribute this observation to the energy transfer between the ZnO NPs and 6CNBP-SH, surface passivation of the ZnO and formation of ZnO nano-dispersing structure induced by 6CNBP-SH molecules. The anisotropic behavior of 6CNBP-SH@ZnO is also investigated. The results indicated that the 6CNBP-SH liquid-crystalline ligands could endow the 6CNBP-SH@ZnO hybrid obvious mesoscopic behavior. In addition, the increased optical anisotropy of 6CNBP-SH@ZnO is also observed upon thermal treatment at 110 °C.Graphical abstractThe successful fabrication of a novel nano-level hybrid of ZnO nanoparticles (NPs) and liquid crystals (LCs) was reported.Enhanced ultra-violet emission and increased optical anisotropy of ZnO were observed in such a hybrid system.Highlights► Successful fabrication of a novel nano-level hybrid of ZnO nanoparticles (NPs) and liquid crystals (LCs) was reported. ► Enhanced ultra-violet emission and increased optical anisotropy of zno were observed in such a hybrid system.
Co-reporter:Fan Li, Yanhui Du, Yiwang Chen, Lie Chen, Jie Zhao, Peishan Wang
Solar Energy Materials and Solar Cells 2012 97() pp: 64-70
Publication Date(Web):
DOI:10.1016/j.solmat.2011.09.002
Co-reporter:Kai Yuan, Fan Li, Lie Chen, Yongfang Li, and Yiwang Chen
The Journal of Physical Chemistry C 2012 Volume 116(Issue 10) pp:6332-6339
Publication Date(Web):February 23, 2012
DOI:10.1021/jp3004079
We offer a novel approach to improve the performance of poly 3-hexylthiophene (P3HT)/ZnO hybrid photovoltaic devices by binding the 4,7-diphenyl-2,1,3-benzothiadiazole-based liquid crystal (LC) with a monothiol end group onto the surface of ZnO nanoparticles (LC-ZnO). The attachment of LC onto ZnO nanoparticles’ surfaces can improve the dispersion of ZnO nanoparticles and can endow the ZnO nanoparticles self-assembled behavior upon annealing at LC state temperature (160 °C). By use of the LC-ZnO as electron acceptors in hybrid solar cells enhances the order and crystallinity of P3HT chains and evolves the microstructure of P3HT/LC-ZnO blend, enabling short-circuit current density (Jsc) to be increased. More interestingly, the order of the P3HT/LC-ZnO blend morphology is significantly enhanced after thermal treatment at 160 °C, indicating that the spontaneous assembly of the LC-ZnO pushes P3HT chains to form oriented nanodispersing structure with highly oriented channel layers upon only heating at LC states, leading to the improved power conversion efficiency by 1.8 fold compared with the device based on P3HT/ZnO, demonstrating that the described self-assembled LC-ZnO hybrids represent a promising strategy toward nanoscale controlled bulk heterojunction solar cells.
Co-reporter:Kai Yuan, Fan Li, Lie Chen, Yiwang Chen
Thin Solid Films 2012 Volume 520(Issue 19) pp:6299-6306
Publication Date(Web):31 July 2012
DOI:10.1016/j.tsf.2012.06.036
A cross-linked block copolymer poly(3-hexylthiophene)-b-poly(zinc dimethacrylate) (P3HT-b-PZn(MA)2), which acted as precursor for the preparation of poly(3-hexylthiophene)/ZnO (P3HT/ZnO) hybrid film by in-situ hydrolysis, was rationally designed and synthesized via nitroxide-mediated in-situ polymerization of zinc methacrylate (Zn(MA)2) using poly(3-hexylthiophene) alkoxyamine (P3HT-TIPNO) as macroinitiator for the purpose of stabilizing the P3HT/ZnO hybrid solar cells. The cross-linking was confirmed by the insolubility of the film in organic solvents and Fourier-transform infrared experiment. With the function of the cross-linked template, the diffusion of ZnO nanoparticles prepared by in-situ hydrolysis could be lowered to suppress the formation of large aggregations, which favored the formation of a better and more stable interpenetrating network and provided more heterojunction interfaces for exciton dissociation. As a result, the inverted device based on cross-linked P3HT/ZnO hybrid film obtained by in situ hydrolyzing P3HT-b-PZn(MA)2 block copolymer yielded a power conversion efficiency of 0.45% under AM 1.5G illumination from a calibrated solar simulator with an intensity of 100 mW/cm2, and the deterioration of the photoconversion performance was suppressed in the hybrid solar cells with the cross-linked P3HT/ZnO compared to cells with non-cross-linked P3HT/ZnO obtained by in situ hydrolyzing P3HT-TIPNO/Zn(MA)2 blend film.Highlights► Cross-linked poly(3-hexylthiophene)-b-poly(zinc dimethacrylate) was synthesized. ► Stable poly(3-hexylthiophene)/ZnO hybrid solar cells were fabricated. ► This strategy integrates the advantages of in-situ and cross-linking. ► The approach shows promise in producing stable inverted hybrid solar cells.
Co-reporter:Wei Chen, Yiwang Chen, Fan Li, Lie Chen, Kai Yuan, Kai Yao, Peishan Wang
Solar Energy Materials and Solar Cells 2012 96() pp: 266-275
Publication Date(Web):
DOI:10.1016/j.solmat.2011.10.009
Co-reporter:Kai Yuan, Fan Li, Yiwang Chen, Xiaofeng Wang and Lie Chen
Journal of Materials Chemistry A 2011 vol. 21(Issue 32) pp:11886-11894
Publication Date(Web):07 Jul 2011
DOI:10.1039/C1JM11652E
We report a novel method to in situ synthesise one-dimensional rodlike ZnO nanocrystals directly in the presence of a self-assembling diblock copolymer, poly(3-hexylthiophene)-b-poly(zinc methacrylate acetate) (P3HT-bbb-PZnMAAc), where the P3HT-bbb-PZnMAAc is acting as a molecular template for geometrical manipulation of rodlike ZnO nanocrystals and, meanwhile, as a precursor for ZnO nanoparticles. HRTEM and SAED reveal that rodlike ZnO nanocrystals are assembled by ZnO nanoparticles with almost the same orientation due to the dipole-induced interaction between adjacent ZnO nanoparticles. SEM images show that the rodlike ZnO nanocrystals are homogenously dispersed in the polymer matrix without obvious macrophase separation and its length can be controlled by adjusting the hydrolysis time. In the nanocomposites, as rodlike ZnO nanocrystals synthesized in a well-defined morphological confinement from the self-assembly of a diblock copolymer dispersed closely to P3HT chains with a high interface area, the photo-generated excitons are easy to separate into electrons and holes at the interfaces, resulting in the strong photoluminescence quenching of 70% observed in the P3HT/ZnO nanocomposite film hydrolyzed for 1 h. These results indicate that this type of P3HT/ZnO nanocomposite films are promising candidates for photovoltaic applications. The device based on P3HT/ZnO nanocomposite films hydrolyzed for 1 h yields a power conversion efficiency of 0.19% under AM 1.5G illumination from a calibrated solar simulator with an intensity of 100 mW cm−2.
Co-reporter:Kai Yao, Lie Chen, Yiwang Chen, Fan Li and Peishan Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 36) pp:13780-13784
Publication Date(Web):12 Aug 2011
DOI:10.1039/C1JM12016F
Novel HT-poly[3-(6′-N,N,N-trimethylammonium)-hexyl thiophene] (P3HTN) is developed and the use of the water-soluble thiophene as an interfacial layer for low-cost poly(3-hexylthiophene):phenyl-C61 butyric acid methyl ester (P3HT:PCBM) organic photovoltaic cells with high stability in air is investigated. When P3HTN is simply inserted between the active layer and the cathode as an interfacial dipole layer by spin-coating, the open-circuit voltage (Voc) and short-circuit current density (Jsc) of photovoltaic cells with high work function Al metal cathodes dramatically increase. Resulting from a reduction of the metal work function and improved electron extraction efficiency, the power conversion efficiency (PCE) of the devices annealed in air is enhanced from 1.8% to 3.28%. In particular, the analogue of the active layer as a buffer layer could improve interchain interactions between the P3HT and the P3HTN to modify the interfacial contact, consequently obtaining an unattainable enhancement Jsc, with respect to the interlayer polymer replaced with an unanalogous conjugated polymer. The results would supply useful information to understand the contribution of an interfacial layer on the photovoltaic performance.
Co-reporter:Wei Chen, Fan Li, Yiwang Chen, Kai Yuan, Lie Chen
Applied Surface Science 2011 Volume 257(Issue 21) pp:8788-8793
Publication Date(Web):15 August 2011
DOI:10.1016/j.apsusc.2011.04.022
Abstract
We have developed a novel method to modifying the surface of ZnO nanorods (ZnO NRs) using p-hexoxyterphenylol (HTph-OH) as liquid crystal ligands. The structure and morphology of the modified ZnO NRs were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and atomic force microscopy (AFM). AFM measurement showed that the dispersion of ZnO NRs could be dramatically improved by the surface modification of HTph-OH and further annealing treatment at its liquid crystal state temperature (150 °C). The remarkable decrease of the annealed composite film roughness is because the HTph-OH chains self-organize into more ordered structure induced by mesogens after annealing treatment, which may push the ZnO NRs to form oriented nano-dispersing structure. The optical properties of the modified ZnO NRs were investigated by UV–vis absorption spectroscopy and photoluminescence spectroscopy (PL). Markedly enhanced band-edge ultraviolet photoluminescence and significantly reduced defect-related emission were observed. We attribute this observation to the nearly perfect surface passivation of the ZnO NRs by the HTph-OH molecules. Meanwhile, UV emission of modified ZnO NRs could be further enhanced by increasing the concentration of HTph-OH and annealing treatment at its liquid crystal state temperature.
Co-reporter:Lin Zhang, Fan Li, Yiwang Chen, Xiaofeng Wang
Journal of Luminescence 2011 Volume 131(Issue 8) pp:1701-1706
Publication Date(Web):August 2011
DOI:10.1016/j.jlumin.2011.03.065
In this paper, a new and simple approach for in-situ preparation of transparent ZnO/poly(metyl methacrylate) (ZnO/PMMA) nanocomposite films was developed. Poly(methyl methacrylate)-co-poly(zinc methacrylate acetate) (PMMA-co-PZnMAAc) copolymer was synthesized via free-radical polymerization between methyl methacrylate (MMA) and zinc methacrylate acetate (ZnMAAc), where asymmetric ZnMAAc with only one terminal double bond (C=C) was applied to act as the precursor for ZnO nanocrystals and could avoid cross-link. Subsequently, transparent ZnO/PMMA nanocomposite films were obtained by in-situ thermal decomposition. Scanning electron microscope (SEM) image revealed that ZnO nanocrystals were homogeneously dispersed in PMMA matrix. With thermal decomposition time increasing, the absorption intensity in UV region and photoluminescence intensity of ZnO/PMMA nanocomposite films enhanced. However, the optical properties diminished when the thermal decomposition temperature increased. The TGA measurement displayed ZnO/PMMA nanocomposite films prepared by the in-situ synthesis method possessed better thermal stability compared with those prepared by the physical blending method and pristine PMMA films.Highlights▶ ZnO/PMMA hybrid films were prepared via free-radical polymerization and in-situ thermal decomposition. ▶ ZnO NCs are homogeneously dispersed in the PMMA matrix and these films have good optical properties. ▶ Thermal stability of these films is improved compared with those of physically blending ones.
Co-reporter:Kai Yao, Yiwang Chen, Lie Chen, Fan Li, Xuee Li, Xingye Ren, Hongming Wang, and Tianxi Liu
Macromolecules 2011 Volume 44(Issue 8) pp:2698-2706
Publication Date(Web):March 18, 2011
DOI:10.1021/ma200179u
The ability to control the molecular organization of electronically active liquid-crystalline polymer provides opportunities to develop easy-to-process yet highly ordered supramolecular systems in the field of photovoltaics. Here, we report a novel donor−acceptor type liquid-crystalline copolymer, poly{9,9-bis[6-(4′-cyanobiphenyloxy)hexyl]fluorene-alt-5,5-(4′,7′-di-2-thienyl-2′,1,3′-benzothiadiazole)}, PFcbpDTBT, which contains both electron-donating fluorene and electron-accepting benzothiadiazole units. Incorporating the electron withdrawing cyanobiphenyl units not only narrowed the band gap of the copolymer but also help main chain form spontaneously through self-organization. The films with structural anisotropy can endow the PFcbpDTBT with special features, including absorption band red-shift; fluorescence enhancement; lower lying LUMO level, and crystallinity improvement. When blended with PCBM, the PFcbpDTBT enables the acceptors to adopt the preferential well-oriented arrangement in both surface and inner of the bulk. Among all the thermal treatments, the mesophase annealing achieves the most obvious effect. From the device annealed at 200 °C, the internal quantum efficiency remains or exceeds 20% throughout the 400−650 nm spectrum and the power conversion efficiency values reaches 1.10% without extensive optimization.
Co-reporter:Xiaoming Peng, Lin Zhang, Yiwang Chen, Fan Li, Weihua Zhou
Applied Surface Science 2010 Volume 256(Issue 9) pp:2948-2955
Publication Date(Web):15 February 2010
DOI:10.1016/j.apsusc.2009.11.056
Abstract
In this paper, a new approach for in situ preparing nanocomposites of conjugated polymers (CPs) and semiconductor nanocrystals was developed. Polythiophene grafted poly(zinc methacrylate) (PTh-g-PZMA) copolymer was synthesized by atom-transfer radical polymerization (ATRP) of zinc methacrylate (ZMA) initiated from the macroinitiator poly(2,5-(3-(bromoisopropyl-carbonyl-oxymethylene) thiophene)) (PTh-Br) with pendant initiator groups. Subsequently, the polythiophene grafted poly(methacrylate)/ZnO (PTh-g-PMA/ZnO) hybrid heterojunction nanocomposites were successfully prepared by in situ hydrolysis of PTh-g-PZMA casting films in alkaline aqueous solution. The structures of PTh-Br, PTh-g-PZMA and PTh-g-PMA/ZnO were confirmed by the proton nuclear magnetic resonance (1H NMR) spectra, Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS). The morphologies of PTh-g-PMA/ZnO films prepared for different hydrolysis time were observed in the cross-sections by scanning electron microscope (SEM). The SEM images revealed that ZnO nanocrystals were uniformly dispersed in polymers without any aggregation and the appearances of ZnO nanocrystals changed from nanoparticles to nanorods with the hydrolysis treatment time increasing. The optical properties of these nanocomposites were studied by ultraviolet–visible (UV–vis) absorption and fluorescence spectroscopy. UV–vis absorption spectroscopy showed that the adsorption band of PTh-g-PMA/ZnO hybrids was broader than that of PTh-Br, implying that the existence of ZnO nanocrystals increased the optical absorption region of hybrids. The photoluminescence (PL) spectra of the hybrids showed that fluorescence quenching occurred in PTh-g-PMA/ZnO blends and a maximum of 85% of the fluorescence intensity quenched in the PTh-g-PMA/ZnO obtained from treatment in NaOH aqueous solution for 2 h, which revealed the existence of photo-induced charge transfer between the polythiophene chains and ZnO. These results indicated that the hybrid heterojunction nanocomposites could be promising candidates for photovoltaic applications.
Co-reporter:Kai Yao, Xiaofeng Wang, Fan Li and Lang Zhou
Chemical Communications 2015 - vol. 51(Issue 84) pp:NaN15433-15433
Publication Date(Web):2015/08/26
DOI:10.1039/C5CC05879A
We have described the compositional engineering of mixed perovskite based on methyl- and polymeric-ammonium. The resulting perovskite films containing moisture-resistant 2D materials exhibit a maximum power conversion efficiency of over 15% with high reproducibility and good stability, offering greater tunability at the molecular level for material optimization.
Co-reporter:Kai Yao, Lie Chen, Yiwang Chen, Fan Li and Peishan Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 36) pp:NaN13784-13784
Publication Date(Web):2011/08/12
DOI:10.1039/C1JM12016F
Novel HT-poly[3-(6′-N,N,N-trimethylammonium)-hexyl thiophene] (P3HTN) is developed and the use of the water-soluble thiophene as an interfacial layer for low-cost poly(3-hexylthiophene):phenyl-C61 butyric acid methyl ester (P3HT:PCBM) organic photovoltaic cells with high stability in air is investigated. When P3HTN is simply inserted between the active layer and the cathode as an interfacial dipole layer by spin-coating, the open-circuit voltage (Voc) and short-circuit current density (Jsc) of photovoltaic cells with high work function Al metal cathodes dramatically increase. Resulting from a reduction of the metal work function and improved electron extraction efficiency, the power conversion efficiency (PCE) of the devices annealed in air is enhanced from 1.8% to 3.28%. In particular, the analogue of the active layer as a buffer layer could improve interchain interactions between the P3HT and the P3HTN to modify the interfacial contact, consequently obtaining an unattainable enhancement Jsc, with respect to the interlayer polymer replaced with an unanalogous conjugated polymer. The results would supply useful information to understand the contribution of an interfacial layer on the photovoltaic performance.
Co-reporter:Kai Yuan, Fan Li, Yiwang Chen, Xiaofeng Wang and Lie Chen
Journal of Materials Chemistry A 2011 - vol. 21(Issue 32) pp:NaN11894-11894
Publication Date(Web):2011/07/07
DOI:10.1039/C1JM11652E
We report a novel method to in situ synthesise one-dimensional rodlike ZnO nanocrystals directly in the presence of a self-assembling diblock copolymer, poly(3-hexylthiophene)-b-poly(zinc methacrylate acetate) (P3HT-bbb-PZnMAAc), where the P3HT-bbb-PZnMAAc is acting as a molecular template for geometrical manipulation of rodlike ZnO nanocrystals and, meanwhile, as a precursor for ZnO nanoparticles. HRTEM and SAED reveal that rodlike ZnO nanocrystals are assembled by ZnO nanoparticles with almost the same orientation due to the dipole-induced interaction between adjacent ZnO nanoparticles. SEM images show that the rodlike ZnO nanocrystals are homogenously dispersed in the polymer matrix without obvious macrophase separation and its length can be controlled by adjusting the hydrolysis time. In the nanocomposites, as rodlike ZnO nanocrystals synthesized in a well-defined morphological confinement from the self-assembly of a diblock copolymer dispersed closely to P3HT chains with a high interface area, the photo-generated excitons are easy to separate into electrons and holes at the interfaces, resulting in the strong photoluminescence quenching of 70% observed in the P3HT/ZnO nanocomposite film hydrolyzed for 1 h. These results indicate that this type of P3HT/ZnO nanocomposite films are promising candidates for photovoltaic applications. The device based on P3HT/ZnO nanocomposite films hydrolyzed for 1 h yields a power conversion efficiency of 0.19% under AM 1.5G illumination from a calibrated solar simulator with an intensity of 100 mW cm−2.
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