Co-reporter:Chao Chen, Liang Wang, Liang Gao, Dahyun Nam, Dengbing Li, Kanghua Li, Yang Zhao, Cong Ge, Hyeonsik Cheong, Huan Liu, Haisheng Song, and Jiang Tang
ACS Energy Letters September 8, 2017 Volume 2(Issue 9) pp:2125-2125
Publication Date(Web):August 21, 2017
DOI:10.1021/acsenergylett.7b00648
Sb2Se3 is a promising candidate for thin-film photovoltaics, with a suitable band gap, benign grain boundaries, Earth-abundant and nontoxic constituents, and excellent stability. However, the low doping density (1013 cm–3) of Sb2Se3 absorber and back contact barrier limit its efficiency. Here we introduced a PbS colloidal quantum dot (CQD) film as the hole-transporting layer (HTL) to construct a n-i-p configured device and overcame these problems. Through simulation-guided optimization, we have significantly improved the efficiency of a Sb2Se3 thin-film solar cell to a new certified record of 6.5%. The PbS CQD HTL not only minimized carrier recombination loss at the back contact and boosted carrier collection efficiency but also contributed photocurrent by its own near-infrared absorption. Furthermore, these n-i-p devices also demonstrated improved device uniformity, achieving 6.39% in a 1.02 cm2 device.
Co-reporter:Chao Chen;David C. Bobela;Ye Yang;Shuaicheng Lu
Frontiers of Optoelectronics 2017 Volume 10( Issue 1) pp:18-30
Publication Date(Web):2017 March
DOI:10.1007/s12200-017-0702-z
Antimony selenide (Sb2Se3) is a promising absorber material for thin film photovoltaics because of its attractive material, optical and electrical properties. In recent years, the power conversion efficiency (PCE) of Sb2Se3 thin film solar cells has gradually enhanced to 5.6%. In this article, we systematically studied the basic physical properties of Sb2Se3 such as dielectric constant, anisotropic mobility, carrier lifetime, diffusion length, defect depth, defect density and optical band tail states.We believe such a comprehensive characterization of the basic physical properties of Sb2Se3 lays a solid foundation for further optimization of solar device performance.
Co-reporter:Zhe Xia, Feng-Xin Yu, Shuai-Cheng Lu, Ding-Jiang Xue, ... Jiang Tang
Chinese Chemical Letters 2017 Volume 28, Issue 4(Volume 28, Issue 4) pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.cclet.2017.03.003
Solution-processed semiconductors such as perovskite compounds have attracted tremendous attention to photovoltaic research due to the significantly higher energy conversion efficiencies and lower processing costs. However, concerns over stability and the toxicity on lead in CH3NH3PbI3 create the need for still easily-accessible but more stable and environmentally friendly materials. Here, we present NaSbS2 as a non-toxic, earth-abundant promising material consisting of densely packed (1/∞) [SbS2−] polymeric chains and sodium ions. The ionic nature makes it sharing the similar dissolution superiority with perovskite, providing great potential for low-cost and large-scale fabrication. Phase pure NaSbS2 thin film was successfully fabricated using spray-pyrolysis method, and its photovoltaic relevant material, optical and electrical properties were carefully studied. Finally, a prototype NaSbS2-based thin-film solar cell has been successfully demonstrated, yielding a power conversion efficiency of 0.13%. The systematic experimental and theoretical investigations, combined with proof-of-principle device results, indicate that NaSbS2 is indeed very promising for photovoltaic application.Download high-res image (137KB)Download full-size imageWe present NaSbS2 as a non-toxic, earth-abundant absorber material for thin film photovoltaics. It consists of covalently bonded (1/∞) [SbS2-] polymeric chains held together by sodium ions, featuring easy dissolution in water due to the ionic nature and fast carrier transport along the covalent backbone. The optoelectronic properties of NaSbS2 film were carefully studied, and a prototype substrate solar cell was successfully built.
Co-reporter:Huaibing Song;Tiaoyang Li;Jia Zhang;Ying Zhou;Jiajun Luo;Chao Chen;Bo Yang;Cong Ge;Yanqing Wu
Advanced Materials 2017 Volume 29(Issue 29) pp:
Publication Date(Web):2017/08/01
DOI:10.1002/adma.201700441
2D materials, particularly those bearing in-plane anisotropic optical and electrical properties such as black phosphorus and ReS2, have spurred great research interest very recently as promising building blocks for future electronics. However, current progress is limited to layered compounds that feature atomic arrangement asymmetry within the covalently bonded planes. Herein, a series of highly anisotropic nanosheets (Sb2Se3, Sb2S3, Bi2S3, and Sb2(S, Se)3), which are composed of 1D covalently linked ribbons stacked together via van der Waals force, is introduced as a new member to the anisotropic 2D material family. These unique anisotropic nanosheets are successfully fabricated from their polymer-like bulk counterparts through a gentle water freezing-thawing approach. Angle-resolved polarized Raman spectroscopy characterization confirms the strong in-plane asymmetry of Sb2Se3 nanosheets, and photodetection study reveals their high responsivity and anisotropic in-plane transport. This work can enlighten the synthesis and application of new anisotropic 2D nanosheets that can be potentially applied for future electronic and optoelectronic devices.
Co-reporter:Liang Gao;Cong Ge;Wenhui Li;Chuancheng Jia;Kai Zeng;Weicheng Pan;Haodi Wu;Yang Zhao;Yisu He;Jungang He;Zhixin Zhao;Guangda Niu;Xuefeng Guo;F. Pelayo Garcia de Arquer;Edward H. Sargent
Advanced Functional Materials 2017 Volume 27(Issue 33) pp:
Publication Date(Web):2017/09/01
DOI:10.1002/adfm.201702360
Conventional narrowband photodetection is enabled by coupling broadband photodetectors with complex optical filters. The recently reported charge collection narrowing, an alternative filter-free strategy, attains very narrowband photodetection at the sacrifice of sensitivity. Herein, a new strategy is proposed to customize the responsive spectrum with high gain by using dye molecules with intrinsically versatile and narrowband absorption. The device configuration is organic dye/Zn0.9Mg0.1O nanoparticles/graphene, where the organic dye serves as the narrowband absorber, graphene serves as the fast carrier transport channel, and Zn0.9Mg0.1O nanoparticles play a triple role of enhancing dye loading, suppressing dye aggregation and blocking charge back recombination. A high responsivity of 8 × 103 A W−1 is thus obtained at a 530 nm response peak with a 60 nm full-width at half maximum, a four orders of magnitude increase in sensitivity compared to the best narrowband photodetectors reported to date under the comparable electric field. Organic dyes with dual-band absorption to demonstrate narrowband photodetectors with customized responsive spectrum are further implemented. The approach opens the way to the realization of efficient flexible narrowband photodetection for electronic skin and wearable electronic applications.
Co-reporter:Chao Chen;Yang Zhao;Shuaicheng Lu;Kanghua Li;Yang Li;Bo Yang;Wenhao Chen;Liang Wang;Dengbing Li;Hui Deng;Fei Yi
Advanced Energy Materials 2017 Volume 7(Issue 20) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/aenm.201700866
AbstractSb2Se3, a V2-VI3 compound semiconductor, has attracted extensive research attention in photovoltaics due to its non-toxicity, low cost and earth-abundant constituents. Herein, a combinatorial approach to optimize the performance of TiO2/Sb2Se3 thin film photovoltaics is employed. By simultaneously conducting a series of experiments in parallel rather than one after another, combinatorial strategy increases experimental throughput and reduces personnel costs. Key parameters such as TiO2 thickness, post-annealing temperature and Sb2Se3 thickness are identified as 65 nm, 450 °C and 850 nm through the combinatorial approach. Finally, in combination with (NH4)2S back surface cleaning, TiO2/Sb2Se3 solar cells with 5.6% efficiency and decent stability are obtained, showcasing the power of high-throughput strategy for accelerating the optimization of Sb2Se3 photovoltaics.
Co-reporter:Xixing Wen, Yisu He, Chao Chen, Xinsheng Liu, Liang wang, Bo Yang, Meiying Leng, Huaibing Song, Kai Zeng, Dengbing Li, Kanghua Li, Liang Gao, Jiang Tang
Solar Energy Materials and Solar Cells 2017 Volume 172(Volume 172) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.solmat.2017.07.014
•Sb2Se3 thin film solar cell was first fabricated using full vacuum method.•A 4.08% ZnO/ Sb2Se3 efficiency was acquired.•Various ZnO annealing atmospheres affects subsequent defect densities.•Ambient annealing served as the optimal ZnO treatment.Sb2Se3 possesses great potential for low-cost photovoltaics due to its excellent optoelectronic properties. CdS was typically used as electron collection layer due to high electron affinity, relatively high electron mobility, and environmental stability. However, the toxicity was a big issue restricting its development. Here we fabricate ZnO films by magnetron sputtering to replace the toxic CdS layer for non-toxic ZnO/Sb2Se3 heterojunction solar cells. It was found that the annealing atmosphere (ambient air or vacuum) played a significant role for the device performance. We found that post-annealing increased the crystallinity of ZnO to some extent. Ambient air annealing reduced the oxygen vacancies in ZnO and vacuum annealing increased oxygen vacancies. The reduced oxygen vacancies in ZnO resulted in an improved p-n junction between ZnO and Sb2Se3 and better device performance. The power conversion efficiency of ZnO/Sb2Se3 solar cell with ZnO film annealed in ambient air reached 4.08%.
Co-reporter:Bo Yang, Chong Wang, Zhenkun Yuan, Shiyou Chen, Yisu He, Huaibing Song, Ruiqing Ding, Yang Zhao, Jiang Tang
Solar Energy Materials and Solar Cells 2017 Volume 168(Volume 168) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.solmat.2017.04.030
•Accurate phase and crystal orientation controls are vital for CuSbSe2 photovoltaics.•The mechanisms for phase and crystal orientation evolution of CuSbSe2 are proposed.•Temperature is the critical factor to control phase and crystal orientation of CuSbSe2.CuSbSe2 has attracted huge attention as an absorber material for thin-film solar cells due to its attractive optical and electrical properties, as well as earth-abundant, low-cost, and low-toxic constituent elements. However, different from the conventional inorganic absorbers such as CdTe, CuSbSe2 has a complicated phase space with at least five competitive phases such as Cu2Se, CuSe, Sb2Se3, Cu3SbSe4, and Cu3SbSe3 and crystallizes in two-dimension (2D) layered structure. Crystal phase and orientation strongly correlate with film properties and thus are crucial for device performance. In this paper, by varying the annealing temperature, we carefully investigated the phase, electrical properties and crystal orientation evolutions of hydrazine solution processed CuSbSe2 films. Intermediate Cu3SbSe3 secondary phase was identified, and the temperature dependent orientation change was observed, which is driven by the reduced surface energy, as supported by the first-principle calculations. Finally, a prototype thin film solar cell is fabricated, achieving 2.70% efficiency. Our theoretical calculation and experimental investigation demonstrated the importance of controlling phase composition and crystal orientation in the application for photovoltaics.
Co-reporter:Liang Gao, Kai Zeng, Jingshu Guo, Cong Ge, Jing Du, Yang Zhao, Chao Chen, Hui Deng, Yisu He, Haisheng Song, Guangda Niu, and Jiang Tang
Nano Letters 2016 Volume 16(Issue 12) pp:7446-7454
Publication Date(Web):November 1, 2016
DOI:10.1021/acs.nanolett.6b03119
Photodetectors convert light signals into current or voltage outputs and are widely used for imaging, sensing, and spectroscopy. Perovskite-based photodetectors have shown high sensitivity and fast response due to the unprecedented low recombination loss in this solution processed semiconductor. Among various types of CH3NH3PbI3 morphology (film, single crystal, nanowire), single-crystalline CH3NH3PbI3 nanowires are particularly interesting for photodetection because of their reduced grain boundary, morphological anisotropy, and excellent mechanical flexibility. The concomitant disadvantage associated with the CH3NH3PbI3 nanowire photodetectors is their large surface area, which catalyzes carrier recombination and material decomposition, thus significantly degrading device performance and stability. Here we solved this key problem by introducing oleic acid soaking to passivate surface defects of CH3NH3PbI3 nanowires, which leads to a device with much improved stability and unprecedented sensitivity (measured detectivity of 2 × 1013 Jones). By taking advantage of their one-dimensional geometry, we also showcased, for the first time, the linear dichroic photodetection of our CH3NH3PbI3 nanowire photodetector.Keywords: high detectivity; passivation; polarization sensitivity; Single-crystalline CH3NH3PbI3 nanowire;
Co-reporter:Long Hu;Deng-Bing Li;Liang Gao;Hua Tan;Chao Chen;Kanghua Li;Min Li;Jun-Bo Han;Haisheng Song;Huan Liu
Advanced Functional Materials 2016 Volume 26( Issue 12) pp:1899-1907
Publication Date(Web):
DOI:10.1002/adfm.201505043
Lead sulfide (PbS) colloidal quantum dots (CQDs) solar cells possess the advantages of absorption into the infrared, solution processing, and multiple exciton generation, making them very competitive as a low-cost photovoltaic alternative. Employing an n-i-p ZnO/tetrabutylammonium (TBAI)–PbS/ethanedithiol (EDT)–PbS device configuration, the present study reports a 9.0% photovoltaic device through ZnMgO electrode engineering and graphene doping. Sol–gel-derived Zn0.9Mg0.1O buffer layer shows better transparency and higher conduction band maximum than ZnO, and incorporation of graphene and chlorinated graphene oxide into the TBAI–PbS and EDT–PbS layer respectively boosts carrier collection, leading to device with significantly enhanced open circuit voltage and short-circuit current density. It is believed that incorporation of graphene into PbS CQD film as proposed here, and more generally nanosheets of other materials, would potentially open a simple and powerful avenue to overcome the carrier transport bottleneck of CQD optoelectronic device, thus pushing device performance to a new level.
Co-reporter:Keke Qiao, Hui Deng, Xiaokun Yang, Dongdong Dong, Min Li, Long Hu, Huan Liu, Haisheng Song and Jiang Tang
Nanoscale 2016 vol. 8(Issue 13) pp:7137-7143
Publication Date(Web):29 Feb 2016
DOI:10.1039/C5NR09069E
Traditional photoconductive photodetectors (PDs) commonly respond to higher energy photons compared with the bandgaps of PD active materials. Different from the wide detection spectra of traditional PDs, the present reported PbS quantum dot (QD) PDs can detect the spectra-selective light source. Spectra-selective PDs (ss-PDs) of perovskite/QDs and QD/QDs were respectively implemented by integrating two functional layers. The top layer (facing the light) was utilized to filter the non-target spectra and the bottom layer was used for detection. The response spectrum wavelength and the range of ss-PDs can be conveniently tailored by tuning the QD size. The obtained selectivity factor and normalized detectivity ratio from target and non-target illumination can reach at least 10. A narrow detection range with a full width at half maximum (FWHM) ∼100 nm was applied by typical QD/QD based ss-PDs. The prototype ss-PDs were successfully applied in identifying an unknown light source. The convenient tuning and identification capabilities of the present QD based ss-PDs may provide a versatile route to obtain highly spectrum-selective PDs in order to meet the demands for special fields.
Co-reporter:Liang Wang, Bo Yang, Zhe Xia, Meiying Leng, Ying Zhou, Ding-Jiang Xue, Jie Zhong, Liang Gao, Haisheng Song, Jiang Tang
Solar Energy Materials and Solar Cells 2016 Volume 144() pp:33-39
Publication Date(Web):January 2016
DOI:10.1016/j.solmat.2015.08.016
•Cu12Sb4S13 film was first fabricated using a hydrazine solution process.•Cu12Sb4S13 could be oxidized to Cu3SbS4 during the sulfurization at 500 °C.•The valence states in our Cu12Sb4S13 film were Cu+10Cu22+Sb3+4S2−13.•Optical and electrical properties of Cu12Sb4S13 film were investigated in detail.•Cu12Sb4S13 thin film solar cells were constructed and obtained a PCE of 0.04%.Cu12Sb4S13 is a very potential non-toxic, earth-abundant absorber material for thin film solar cells yet its photovoltaic related properties are rarely explored so far. In this paper, we first developed a hydrazine solution process to fabricate phase-pure, highly crystalline, large grain Cu12Sb4S13 film and then carried out investigations to study the chemical, optical and electrical properties of Cu12Sb4S13 film in detail. Careful X-ray photoelectron spectroscopy (XPS) measurements indicated Cu12Sb4S13 could be oxidized into Cu3SbS4 in a sulfur rich atmosphere at elevated temperature, and the valance states of our Cu12Sb4S13 are determined as Cu+12Sb3+3Sb5+1S2−13 rather than the previously reported Cu+10Cu22+Sb3+4S2−13. Optical absorption investigation showed that Cu12Sb4S13 has a direct band gap of 1.47 eV. Ultraviolet photoelectron spectroscopy (UPS) study revealed that the conduction band and valence band are located at −3.52 eV and −4.99 eV relative to the vacuum level, respectively. Finally, we built a photodetector based on Cu12Sb4S13 film achieving 0.15 A/W responsivity and a heterojunction solar cell having 0.04% solar conversion efficiency. Our preliminary experimental study indicated that Cu12Sb4S13 may be a very attractive absorber material for photovoltaic application.
Co-reporter:Huaibing Song, Xiaojun Zhan, Dengbing Li, Ying Zhou, Bo Yang, Kai Zeng, Jie Zhong, Xiangshui Miao, Jiang Tang
Solar Energy Materials and Solar Cells 2016 Volume 146() pp:1-7
Publication Date(Web):March 2016
DOI:10.1016/j.solmat.2015.11.019
•High quality Bi2S3 film was fabricated by a rapid thermal evaporation process.•Optical and electrical properties of Bi2S3 film were investigated in detail.•ITO/NiO/Bi2S3/Au thin film solar cells obtained an efficiency of 0.75%.Bi2S3 is a promising inorganic material for thin film photovoltaic application with optimum direct band gap of ~1.3 eV, strong absorption coefficient, nontoxic and simple composition. Here we introduce rapid thermal evaporation (RTE), a method with simple facility and extremely fast deposition speed, to produce high quality Bi2S3 films. By optimizing the substrate temperature and post-annealing process, well-crystalline, smooth and compact Bi2S3 films were obtained. The band gap, doping type and density, and photosensitivity of as-produced Bi2S3 films were revealed by a combined X-ray diffraction, Scanning electron microscopy (SEM), Raman spectrum, X-ray photoelectron spectroscopy (XPS), Energy dispersive spectroscopy (EDS), Hall effect and photoresponse measurements. Finally, a prototypical ITO/NiO/Bi2S3/Au solar cell with 0.75% power conversion efficiency was obtained, manifesting the promise of Bi2S3 as the absorber layer for thin film photovoltaics.
Co-reporter:Liang Gao, Chao Chen, Kai Zeng, Cong Ge, Dun Yang, Haisheng Song and Jiang Tang
Light: Science & Applications 2016 5(7) pp:e16126
Publication Date(Web):2016-03-08
DOI:10.1038/lsa.2016.126
Photodetectors convert photons into current or voltage outputs and are thus widely used for spectroscopy, imaging and sensing. Traditional photodetectors generally show a consistent-polarity response to incident photons within their broadband responsive spectrum. Here we introduced a new type of photodetector employing SnS2 nanosheets sensitized with PbS colloidal quantum dots (CQDs) that are not only sensitive (~105 A W−1) and broadband (300–1000 nm) but also spectrally distinctive, that is, show distinctive (positive or negative) photoresponse toward incident photons of different wavelengths. A careful mechanism study revealed illumination-modulated Schottky contacts between SnS2 nanosheets and Au electrodes, altering the photoresponse polarity toward incident photons of different wavelengths. Finally, we applied our SnS2 nanosheet/PbS CQDs hybrid photodetector to differentiate the color temperature of emission from a series of white light-emitting diodes (LEDs), showcasing the unique application of our novel photodetectors.
Co-reporter:Deng-Bing Li, Long Hu, Yao Xie, Guangda Niu, Tiefeng Liu, Yinhua Zhou, Liang Gao, Bo Yang, and Jiang Tang
ACS Photonics 2016 Volume 3(Issue 11) pp:2122
Publication Date(Web):October 12, 2016
DOI:10.1021/acsphotonics.6b00582
Organic–inorganic hybrid perovskite solar cells have attracted great attention due to their unique properties and rapid increased power conversion efficiency. Currently, PC61BM is widely used as the electron transport layer (ETL) for inverted hybrid perovksite solar cells. Here we propose and demonstrate that Bi2S3, a ribboned compound with intrinsic high mobility and stability, could be used as the ETL for perovksite solar cells. Through a simple thermal evaporation with the substrate kept at room temperature, we successfully produced a compact and smooth amorphous Bi2S3 ETL with high conductivity. Our NiO/CH3NH3PbI3/Bi2S3 solar cell achieved a device efficiency of 13%, which is comparable with our counterpart device using PC61BM as the ETL. Moreover, our device showed much improved ambient storage stability due to the hydrophobic and hermetic encapsulation of the perovskite layer by the Bi2S3 ETL. We believe thermally evaporated Bi2S3 is a promising ETL for inverted hybrid perovskite solar cells and worthy of further exploration.Keywords: Bi2S3; electron transfer layer; hybrid perovskite; low-temperature process; thermal evaporation
Co-reporter:Ding-Jiang Xue;Bo Yang;Zhen-Kun Yuan;Gang Wang;Xinsheng Liu;Ying Zhou;Long Hu;Daocheng Pan;Shiyou Chen
Advanced Energy Materials 2015 Volume 5( Issue 23) pp:
Publication Date(Web):
DOI:10.1002/aenm.201501203
CuSbSe2 appears to be a promising absorber material for thin-film solar cells due to its attractive optical and electrical properties, as well as earth-abundant, low-cost, and low-toxic constituent elements. However, no systematic study on the fundamental properties of CuSbSe2 has been reported, such as defect physics, material, optical, and electrical properties, which are highly relevant for photovoltaic application. First, using density functional theory calculations, CuSbSe2 is shown to have benign defect properties, i.e., free of recombination-center defects, and flexible defect and carrier concentration which can be tuned through the control of growth condition. Next, systematic material, optical, and electrical characterizations uncover many unexplored fundamental properties of CuSbSe2 including band position, temperature-dependent band gap energy, Raman spectrum, and so on, thus providing a solid foundation for further photovoltaic research. Finally, a prototype CuSbSe2-based thin film solar cell is fabricated by a hydrazine solution process. The systematic theoretical and experimental investigation, combined with the preliminary efficiency, confirms the great potential of CuSbSe2 for thin-film solar cell applications.
Co-reporter:Long Hu, Weiwei Wang, Huan Liu, Jun Peng, Hefeng Cao, Gang Shao, Zhe Xia, Wanli Ma and Jiang Tang
Journal of Materials Chemistry A 2015 vol. 3(Issue 2) pp:515-518
Publication Date(Web):24 Nov 2014
DOI:10.1039/C4TA04272G
Here, we applied colloidal quantum dots (CQDs) as an effective p-type hole-transporting material (HTM) for planar heterojunction perovskite solar cells. By tuning the size of PbS CQDs, we engineered the energy alignment of the valence and conduction band of this new HTM with the perovskite light harvester and achieved conversion efficiencies up to 7.5%. Absorption of PbS CQDs also extends the absorption spectrum of perovskite solar cells into the infrared region.
Co-reporter:Long Hu, Gang Shao, Tao Jiang, Dengbing Li, Xinlin Lv, Hongya Wang, Xinsheng Liu, Haisheng Song, Jiang Tang, and Huan Liu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 45) pp:25113
Publication Date(Web):October 26, 2015
DOI:10.1021/acsami.5b06268
Organometal halide perovskites have recently emerged as outstanding semiconductors for solid-state optoelectronic devices. Their sensitivity to moisture is one of the biggest barriers to commercialization. In order to identify the effect of moisture in the degradation process, here we combined the in situ electrical resistance measurement with time-resolved X-ray diffraction analysis to investigate the interaction of CH3NH3PbI3−xClx perovskite films with moisture. Upon short-time exposure, the resistance of the perovskite films decreased and it could be fully recovered, which were ascribed to a mere chemisorption of water molecules, followed by the reversible hydration into CH3NH3PbI3–xClx·H2O. Upon long-time exposure, however, the resistance became irreversible due to the decomposition into PbI2. The results demonstrated the formation of monohydrated intermediate phase when the perovskites interacted with moisture. The role of moisture in accelerating the thermal degradation at 85 °C was also demonstrated. Furthermore, our study suggested that the perovskite films with fewer defects may be more inherently resistant to moisture.Keywords: degradation; electrical resistance; hydration; moisture; perovskite films
Co-reporter:Jiang Tang
Frontiers of Optoelectronics 2015 Volume 8( Issue 3) pp:239-240
Publication Date(Web):2015 September
DOI:10.1007/s12200-015-0546-3
Co-reporter:Huan Liu;Min Li;Oleksr Voznyy;Long Hu;Qiuyun Fu;Dongxiang Zhou;Zhe Xia;Edward H. Sargent
Advanced Materials 2014 Volume 26( Issue 17) pp:2718-2724
Publication Date(Web):
DOI:10.1002/adma.201304366
Co-reporter:Ying Zhou;Meiying Leng;Zhe Xia;Jie Zhong;Huaibing Song;Xinsheng Liu;Bo Yang;Junpei Zhang;Jie Chen;Kunhao Zhou;Junbo Han;Yibing Cheng
Advanced Energy Materials 2014 Volume 4( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/aenm.201301846
Co-reporter:Bo Yang, Liang Wang, Jun Han, Ying Zhou, Huaibing Song, Shiyou Chen, Jie Zhong, Lu Lv, Dongmei Niu, and Jiang Tang
Chemistry of Materials 2014 Volume 26(Issue 10) pp:3135
Publication Date(Web):May 5, 2014
DOI:10.1021/cm500516v
Recently, CuSbS2 has been proposed as an alternative earth-abundant absorber material for thin film solar cells. However, no systematic study on the chemical, optical, and electrical properties of CuSbS2 has been reported. Using density functional theory (DFT) calculations, we showed that CuSbS2 has superior defect physics with extremely low concentration of recombination-center defects within the forbidden gap, espeically under the S rich condition. It has intrinsically p-type conductivity, which is determined by the dominant Cu vacancy (VCu) defects with the a shallow ionization level and the lowest formation energy. Using a hydrazine based solution process, phase-pure, highly crystalline CuSbS2 film with large grain size was successfully obtained. Optical absorption investigation revealed that our CuSbS2 has a direct band gap of 1.4 eV. Ultraviolet photoelectron spectroscopy (UPS) study showed that the conduction band and valence band are located at 3.85 eV and −5.25 eV relative to the vacuum level, respectively. As the calculations predicted, a p-type conductivity is observed in the Hall effect measurements with a hole concentration of ∼1018 cm–3 and hole mobility of 49 cm2/(V s). Finally, we have built a prototype FTO/CuSbS2/CdS/ZnO/ZnO:Al/Au solar cell and achieved 0.50% solar conversion efficiency. Our theoretical and experimental investigation confirmed that CuSbS2 is indeed a very promising absorber material for solar cell application.
Co-reporter:Jie Zhong, Zhe Xia, Cheng Zhang, Bing Li, Xinsheng Liu, Yi-Bing Cheng, and Jiang Tang
Chemistry of Materials 2014 Volume 26(Issue 11) pp:3573
Publication Date(Web):May 12, 2014
DOI:10.1021/cm501270j
Copper zinc tin sulfide/selenide (CZTS/Se) is very promising for photovoltaic application because of their nontoxic, earth-abundant components and excellent optoelectronic properties. Herein, a novel in situ self-stabilization process using water as the only solvent is reported to produce CZTS nanoink. Aqueous processed metal chalcogenide complexes Sn2S64– and Sn2S76– were employed as the self-component ligands to in-situ cap the Cu/Zn sulfide nanoparticles, resulting in homogeneous and stable nanoinks. Through rational materials choice and annealing design, carbon, oxygen, and nitrogen contaminations were minimized in the final film. Finally, high quality CZTSSe film was integrated into a photovoltaic device achieving a preliminary solar conversion efficiency of 5.14%. The innovation of green, stable, scalable, and reliable quality aqueous CZTS nanoinks will further benefit the advancement of high-efficiency, low-cost CZTS solar cells.
Co-reporter:Jungang He, Miao Luo, Long Hu, Yongli Zhou, Shenglin Jiang, Haisheng Song, Rui Ye, Jie Chen, Liang Gao, Jiang Tang
Journal of Alloys and Compounds 2014 Volume 596() pp:73-78
Publication Date(Web):25 May 2014
DOI:10.1016/j.jallcom.2014.01.194
•Flexible PbS colloidal quantum dot photoconductive photodetector is presented.•High device detectivity of 1 × 1010 Jones is obtained.•4B pencil drawn electrodes was employed as the Ohmic contact.•Au nanocrystals were incorporated to improve device performance.Photoconductive photodetector fabricated from lead sulfide (PbS) colloidal quantum dots (CQDs) has demonstrated extremely high sensitivity and detectivity, in addition to their low-cost solution process. In this report we presented an extremely low-cost and flexible PbS photodetector using stone paper as the substrates and pencil drawn graphite as the electrodes. Single crystalline PbS CQDs and Au nanocrystals (NCs) with diameter of 3.2 nm and 7.5 nm were synthesized from the hot injection method. Layer-by-layer spin-coating was applied to construct the absorbing layer. By applying cetyltrimethylammonium bromide (CTAB) for the treatment and incorporating Au NCs into PbS CQD film, we have successfully built a fast and flexible device with detectivity up to 1.1 × 1010 Jones and 3 dB bandwidth of 61.2 Hz. Our flexible CQD photodetector might find its application in next generation flexible optoelectronic device.Graphical abstract
Co-reporter:Jungang He, Keke Qiao, Liang Gao, Haisheng Song, Long Hu, Shenglin Jiang, Jie Zhong, and Jiang Tang
ACS Photonics 2014 Volume 1(Issue 10) pp:936
Publication Date(Web):September 12, 2014
DOI:10.1021/ph500227u
PbS colloidal quantum dot (CQD) photodetectors hold great potential for near-infrared detection due to their extremely high sensitivity and low-cost solution processing. In this paper we report that incorporation of 0.5% to 1% (by weight) Ag nanocrystals (NCs) into the PbS CQDs film could simultaneously enhance the photocurrent and suppress dark current and hence significantly boost device detectivity. A set of control experiments suggested that Ag NCs, once added to the PbS CQD film, could trap photogenerated electrons from neighboring PbS CQDs, extend carrier lifetime, and increase photocurrent. We further built a sensitive flexible photodetector using the optimized composite on stone paper, achieving an estimated detectivity as high as 1.5 × 1010 Jones. The synergetic effect found in our PbS CQD/Ag NC composite photodetectors is expected to be extendable to other binary NC systems for various applications.Keywords: Ag nanocrystals; flexibility; nanocomposites; PbS colloidal quantum dots; photodetectors
Co-reporter:Jun Han;Ying Zhou;Yang Tian;Ziheng Huang;Xiaohua Wang
Frontiers of Optoelectronics 2014 Volume 7( Issue 1) pp:37-45
Publication Date(Web):2014 March
DOI:10.1007/s12200-014-0389-3
Copper tin sulfide (Cu2SnS3) was a potential earth abundant absorber material for photovoltaic device application. In this contribution, triclinic Cu2SnS3 film with phase pure composition and large grain size was fabricated from a hydrazine solution process using Cu, Sn and S as the precursors. Absorption measurement revealed this Cu2SnS3 film had a direct optical band gap of 0.88 eV, and Hall effect measurement indicated the film was p-type with hole mobility of 0.86 cm2/Vs. Finally Mo/Cu2SnS3/CdS/ZnO/AZO/Au was produced and the best device efficiency achieved was 0.78%. Also, this device showed improved device performance during ambient storage. This study laid some foundation for the further improvement of Cu2SnS3 solar cell.
Co-reporter:Long Hu, Jun Peng, Weiwei Wang, Zhe Xia, Jianyu Yuan, Jialing Lu, Xiaodong Huang, Wanli Ma, Huaibing Song, Wei Chen, Yi-Bing Cheng, and Jiang Tang
ACS Photonics 2014 Volume 1(Issue 7) pp:547
Publication Date(Web):June 18, 2014
DOI:10.1021/ph5000067
The new emerging organometal trihalide perovskite holds great potential for high-efficiency, low-cost solar cells because of its high solar to electricity conversation efficiency (>16%) achieved within 4 years of research and its low-temperature solution processing. In this Letter we introduce NiO as the hole-collecting and -conducting layer in perovskite solar cells. Through a modified sequential deposition strategy, we successfully fabricated high-quality CH3NH3PbI3 onto a planar NiO layer and built a planar inverted ITO/NiO/CH3NH3PbI3/PCBM/Al photovoltaic device. A device efficiency of 7.6% was achieved with an impressively high open-circuit voltage (Voc) of 1.05 V. Our study demonstrates the potential application of a deep work function NiO layer for perovskite solar cells.Keywords: NiO; perovskite; sequential deposition; solar cell
Co-reporter:Li Peng;Mingqiang Zhu
Frontiers of Optoelectronics 2012 Volume 5( Issue 4) pp:358-370
Publication Date(Web):2012 December
DOI:10.1007/s12200-012-0285-7
The increasing demand for sustainable and green energy supply spurred the surging research on high-efficiency, low-cost photovoltaics. Colloidal quantum dot solar cell (CQDSC) is a new type of photovoltaic device using lead chalcogenide quantum dot film as absorber materials. It not only has a potential to break the 33% Shockley-Queisser efficiency limit for single junction solar cell, but also possesses low-temperature, high-throughput solution processing. Since its first report in 2005, CQDSCs experienced rapid progress achieving a certified 7% efficiency in 2012, an averaged 1% efficiency gain per year. In this paper, we reviewed the research progress reported in the last two years. We started with background introduction and motivation for CQDSC research. We then briefly introduced the evolution history of CQDSC development as well as multiple exciton generation effect. We further focused on the latest efforts in improving the light absorption and carrier collection efficiency, including the bulk-heterojunction structure, quantum funnel concept, band alignment optimization and quantum dot passivation. Afterwards, we discussed the tandem solar cell and device stability, and concluded this article with a perspective. Hopefully, this review paper covers the major achievement in this field in year 2011–2012 and provides readers with a concise and clear understanding of recent CQDSC development.
Co-reporter:Xinsheng Liu ; Jie Chen ; Miao Luo ; Meiying Leng ; Zhe Xia ; Ying Zhou ; Sikai Qin ; Ding-Jiang Xue ; Lu Lv ; Han Huang ; Dongmei Niu
ACS Applied Materials & Interfaces () pp:
Publication Date(Web):
DOI:10.1021/am502427s
Sb2Se3 is a promising absorber material for photovoltaic cells because of its optimum band gap, strong optical absorption, simple phase and composition, and earth-abundant and nontoxic constituents. However, this material is rarely explored for photovoltaic application. Here we report Sb2Se3 solar cells fabricated from thermal evaporation. The rationale to choose thermal evaporation for Sb2Se3 film deposition was first discussed, followed by detailed characterization of Sb2Se3 film deposited onto FTO with different substrate temperatures. We then studied the optical absorption, photosensitivity, and band position of Sb2Se3 film, and finally a prototype photovoltaic device FTO/Sb2Se3/CdS/ZnO/ZnO:Al/Au was constructed, achieving an encouraging 2.1% solar conversion efficiency.
Co-reporter:Long Hu, Weiwei Wang, Huan Liu, Jun Peng, Hefeng Cao, Gang Shao, Zhe Xia, Wanli Ma and Jiang Tang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 2) pp:NaN518-518
Publication Date(Web):2014/11/24
DOI:10.1039/C4TA04272G
Here, we applied colloidal quantum dots (CQDs) as an effective p-type hole-transporting material (HTM) for planar heterojunction perovskite solar cells. By tuning the size of PbS CQDs, we engineered the energy alignment of the valence and conduction band of this new HTM with the perovskite light harvester and achieved conversion efficiencies up to 7.5%. Absorption of PbS CQDs also extends the absorption spectrum of perovskite solar cells into the infrared region.
