共查询到20条相似文献,搜索用时 31 毫秒
1.
Jing Wei Fengwan Guo Bing Liu Xiangyu Sun Xi Wang Zijiang Yang Kun Xu Ming Lei Yicheng Zhao Dongsheng Xu 《Liver Transplantation》2019,9(40)
Although planar‐structured perovskite solar cells (PSCs) have power conversion efficiencies exceeding 24%, the poor photostability, especially with ultraviolet irradiance (UV) severely limits commercial application. The most commonly‐used TiO2 electron selective layer has a strong photocatalytic effect on perovskite/TiO2 interface when TiO2 is excited by UV light. Here a UV‐inert ZnTiO3 is reported as the electron selective layer in planar PSCs. ZnTiO3 is a perovskite‐structured semiconductor with excellent chemical stability and poor photocatalysis. Solar cells are fabricated with a structure of indium doped tin oxide (ITO)/ZnTiO3/Cs0.05FA0.81MA0.14PbI2.55Br0.45/Sprio‐MeOTAD/Au. The champion device exhibits a stabilized power conversion efficiency of 19.8% with improved photostability. The device holds 90% of its initial efficiency after 100 h of UV soaking (365 nm, 8 mW cm?2), compared with 55% for TiO2‐based devices. This work provides a new class of electron selective materials with excellent UV stability in perovskite solar cell applications. 相似文献
2.
Sara Trost Kirill Zilberberg Andreas Behrendt Andreas Polywka Patrick Görrn Philip Reckers Julia Maibach Thomas Mayer Thomas Riedl 《Liver Transplantation》2013,3(11):1437-1444
A common phenomenon of organic solar cells (OSCs) incorporating metal‐oxide electron extraction layers is the requirement to expose the devices to UV light in order to improve device characteristics – known as the so‐called “light‐soaking” issue. This behaviour appears to be of general validity for various metal‐oxide layers, various organic donor/acceptor systems, and regardless if single junction devices or multi stacked cells are considered. The requirement of UV exposure of OSCs may impose severe problems if substrates with limited UV transmission, UV blocking filters or UV to VIS down‐conversion concepts are applied. In this paper, we will demonstrate that this issue can be overcome by the use of Al doped ZnO (AZO) as electron extraction interlayer. In contrast to devices based on TiOx and ZnO, the AZO devices show well‐behaved solar cell characteristics with a high fill factor (FF) and power conversion efficiency (PCE) even without the UV spectral components of the AM1.5 solar spectrum. As opposed to previous claims, our results indicate that the origin of s‐shaped characteristics of the OSCs is the metal‐oxide/organic interface. The electronic structures of the TiOx/fullerene and AZO/fullerene interfaces are studied by photoelectron spectroscopy, revealing an electron extraction barrier for the TiOx/fullerene case and facilitated electron extraction for AZO/fullerene. These results are of general relevance for organic solar cells based on various donor acceptor active systems. 相似文献
3.
Lessons Learnt from Spatially Resolved Electro‐ and Photoluminescence Imaging: Interfacial Delamination in CH3NH3PbI3 Planar Perovskite Solar Cells upon Illumination
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Arman Mahboubi Soufiani Ziv Hameiri Steffen Meyer Sean Lim Murad Jehangir Yusuf Tayebjee Jae Sung Yun Anita Ho‐Baillie Gavin J. Conibeer Leone Spiccia Martin A. Green 《Liver Transplantation》2017,7(9)
The influence of illumination on the long‐term performance of planar structured perovskite solar cells (PSCs) is investigated using fast and spatially resolved luminescence imaging. The authors analyze the effect of illuminated current density–voltage (J–V) and light‐soaking measurements on pristine PSCs by providing visual evidence for the spatial inhomogeneous evolution of device performance. Regions that are exposed to light initially produce stronger electroluminescence signals than surrounding unilluminated regions, mainly due to a lower contact resistance and, possibly, higher charge collection efficiency. Over a period of several days, however, these initially illuminated regions appear to degrade more quickly despite the device being stored in a dark, moisture‐ and oxygen‐free environment. Using transmission electron microscopy, this accelerated degradation is attributed to delamination between the perovskite and the titanium dioxide (TiO2) layer. An ion migration mechanism is proposed for this delamination process, which is in accordance with previous current–voltage hysteresis observations. These results provide evidence for the intrinsic instability of CH3NH3PbI3‐based devices under illumination and have major implications for the design of PSCs from the standpoint of long‐term performance and stability. 相似文献
4.
Ling Xu Yan Xiong Anyi Mei Yue Hu Yaoguang Rong Yinhua Zhou Bin Hu Hongwei Han 《Liver Transplantation》2018,8(13)
An efficient perovskite photovoltaic‐thermoelectric hybrid device is demonstrated by integrating the hole‐conductor‐free perovskite solar cell based on TiO2/ZrO2/carbon structure and the thermoelectric generator. The whole solar spectrum of AM 1.5 G is fully utilized with the ≈1.55 eV band gap perovskite (5‐AVA)x(MA)1?xPbI3 absorbing the visible light and the carbon back contact absorbing the infrared light. The added thermoelectric generator improves the device performance by converting the thermal energy into electricity via the Seebeck effect. An optimized hybrid device is obtained with a maximum point power output of 20.3% and open‐circuit voltage of 1.29 V under the irradiation of 100 mW cm?2. 相似文献
5.
Minwoo Nam Jin Young Huh Yongkook Park Yong Cheol Hong Doo‐Hyun Ko 《Liver Transplantation》2018,8(14)
Optimizing the interfacial contacts between the photoactive layer and the electrodes is an important factor in determining the performance of organic solar cells (OSCs). A charge‐selective layer with tailored electrical properties enhances the charge collection efficiency and interfacial stability. Here, the potential of hydrogenated TiO2 nanoparticles (H‐TiO2 NPs) as an efficient electron‐selective layer (ESL) material in OSCs is reported for the first time. The H‐TiO2 is synthesized by discharge plasma in liquid at atmospheric pressure, which has the benefits of a simple one‐pot synthesis process, rapid and mild reaction conditions, and the capacity for mass production. The H‐TiO2 exhibits high conductivity and favorable energy level formation for efficient electron extraction, providing a basis for an efficient bilayer ESL system composed of conjugated polyelectrolyte/H‐TiO2. Thus, the enhanced charge transport and extraction efficiency with reduced recombination losses at the cathode interfacial contacts is achieved. Moreover, the OSCs composed of H‐TiO2 are almost free of light soaking, which has been reported to severely limit the performance and stability of OSCs based on conventional TiO2 ESLs. Therefore, H‐TiO2 as a new efficient, stable, and cost‐effective ESL material has the potential to open new opportunities for optoelectronic devices. 相似文献
6.
Outstanding Performance of Hole‐Blocking Layer‐Free Perovskite Solar Cell Using Hierarchically Porous Fluorine‐Doped Tin Oxide Substrate
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Haejun Yu Jong Woo Lee Juyoung Yun Kisu Lee Jaehoon Ryu Jungsup Lee Doyk Hwang Seong Keun Kim Jyongsik Jang 《Liver Transplantation》2017,7(22)
Perovskite solar cells (PSCs) are of great interest in current photovoltaic research due to their extraordinary power conversion efficiency of ≈20% and boundless potentialities. The high efficiency has been mostly obtained from TiO2‐based PSCs, where TiO2 is utilized as a hole‐blocking, mesoporous layer. However, trapped charges and the light‐induced photocatalytic effect of TiO2 seriously degrade the perovskite and preclude PSCs from being immediately commercialized. Herein, a simplified PSC is successfully fabricated by eliminating the problematic TiO2 layers, using instead a fluorine‐doped tin oxide (FTO)/perovskite/hole–conductor/Au design. Simultaneously, the sluggish charge extraction at the FTO/perovskite interface is overcome by modifying the surface of the FTO to a porous structure using electrochemical etching. This surface engineering enables a substantial increase in the photocurrent density and mitigation of the hysteretic behavior of the pristine FTO‐based PSC; a remarkable 19.22% efficiency with a low level of hysteresis is obtained. This performance is closely approaching that of conventional PSCs and may facilitate their commercialization due to improved convenience, lower cost, greater stability, and potentially more efficient mass production. 相似文献
7.
Surface Engineering of TiO2 ETL for Highly Efficient and Hysteresis‐Less Planar Perovskite Solar Cell (21.4%) with Enhanced Open‐Circuit Voltage and Stability
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Interfacial studies and band alignment engineering on the electron transport layer (ETL) play a key role for fabrication of high‐performance perovskite solar cells (PSCs). Here, an amorphous layer of SnO2 (a‐SnO2) between the TiO2 ETL and the perovskite absorber is inserted and the charge transport properties of the device are studied. The double‐layer structure of TiO2 compact layer (c‐TiO2) and a‐SnO2 ETL leads to modification of interface energetics, resulting in improved charge collection and decreased carrier recombination in PSCs. The optimized device based on a‐SnO2/c‐TiO2 ETL shows a maximum power conversion efficiency (PCE) of 21.4% as compared to 19.33% for c‐TiO2 based device. Moreover, the modified device demonstrates a maximum open‐circuit voltage (Voc) of 1.223 V with 387 mV loss in potential, which is among the highest reported value for PSCs with negligible hysteresis. The stability results show that the device on c‐TiO2/a‐SnO2 retains about 91% of its initial PCE value after 500 h light illumination, which is higher than pure c‐TiO2 (67%) based devices. Interestingly, using a‐SnO2/c‐TiO2 ETL the PCE loss was only 10% of initial value under continuous UV light illumination after 30 h, which is higher than that of c‐TiO2 based device (28% PCE loss). 相似文献
8.
Interfacing Pristine C60 onto TiO2 for Viable Flexibility in Perovskite Solar Cells by a Low‐Temperature All‐Solution Process
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Ya‐Qing Zhou Bao‐Shan Wu Guan‐Hua Lin Zhou Xing Shu‐Hui Li Lin‐Long Deng Di‐Chun Chen Da‐Qin Yun Su‐Yuan Xie 《Liver Transplantation》2018,8(20)
A low‐temperature solution‐processed strategy is critical for cost‐effective manufacture of flexible perovskite solar cells (PSCs). Based on an aqueous‐processed TiO2 layer, and conventional fullerene derivatives replaced by a pristine fullerene interlayer of C60, herein a facile interface engineering for making all‐solution‐processed TiO2/C60 layers in flexible n‐i‐p PSCs is reported. Due to the improvement of the perovskite grain quality, promotion of interfacial charge transfer and suppression of interfacial charge recombination, the stabilized power conversion efficiency for the flexible PSCs reaches as high as 16% with high bending resistance retention (≈80% after 1500 cycles) and high light‐soaking retention (≈100% after 100 min). In addition, the stabilized efficiency is over 19% for the rigid TiO2/C60‐based PSCs. The present work with the facile low‐temperature solution process renders the practicability for high‐performance flexible PSCs applied to wearable devices, portable equipment, and electric vehicles. 相似文献
9.
Dual Functional Electron‐Selective Contacts Based on Silicon Oxide/Magnesium: Tailoring Heterointerface Band Structures while Maintaining Surface Passivation
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Hui Tong Zhenhai Yang Xixi Wang Zhaolang Liu Zhenxin Chen Xiaoxing Ke Manling Sui Jiang Tang Tianbao Yu Ziyi Ge Yuheng Zeng Pingqi Gao Jichun Ye 《Liver Transplantation》2018,8(16)
Silicon (Si)‐based dopant‐free heterojunction solar cells (SCs) featuring carrier‐selective contacts (CSCs) have attracted considerable interest due to the extreme simplifications in their device structure and manufacturing procedure. However, these SCs are limited by the unsatisfactory contact properties on both sides of the junction, and their efficiencies are not comparable with those of commercially available Si SCs. In this report, a high‐performance silicon‐oxide/magnesium (SiOx/Mg) electron‐selective contact (ESC) design is described. Combining an ultrathin SiOx and a low work function Mg layer, the novel ESC simultaneously yields low recombinative and resistive losses. In addition, deposition of Mg on SiOx relaxes the restriction on the threshold thickness of the SiOx for electron tunneling and therefore broadens the optimization space for rear‐sided passivation. Meanwhile, hole‐selective contact with boosted light harvesting and suppressed interfacial recombination is achieved by forming a fully conformal contact between the conducting poly(3,4‐ethylene dioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) and periodic Si pyramid arrays. With the double‐sided carrier‐selective contact designs, PEDOT: PSS/Si/SiOx/Mg SCs with efficiency of 15% are finally obtained via a totally dopant‐free processing. Subsequent calculations further indicate a pathway for the improvement of these contacts toward an efficiency that is competitive with conventionally diffused pn junction SCs. 相似文献
10.
Linking Vertical Bulk‐Heterojunction Composition and Transient Photocurrent Dynamics in Organic Solar Cells with Solution‐Processed MoOx Contact Layers
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It is demonstrated that a combination of microsecond transient photocurrent measurements and film morphology characterization can be used to identify a charge‐carrier blocking layer within polymer:fullerene bulk‐heterojunction solar cells. Solution‐processed molybdenum oxide (s‐MoOx) interlayers are used to control the morphology of the bulk‐heterojunction. By selecting either a low‐ or high‐temperature annealing (70 °C or 150 °C) for the s‐MoOx layer, a well‐performing device is fabricated with an ideally interconnected, high‐efficiency morphology, or a device is fabricated in which the fullerene phase segregates near the hole extracting contact preventing efficient charge extraction. By probing the photocurrent dynamics of these two contrasting model systems as a function of excitation voltage and light intensity, the optoelectronic responses of the solar cells are correlated with the vertical phase composition of the polymer:fullerene active layer, which is known from dynamic secondary‐ion mass spectroscopy (DSIMS). Numerical simulations are used to verify and understand the experimental results. The result is a method to detect poor morphologies in operating organic solar cells. 相似文献
11.
Low‐Temperature Solution‐Processed CuCrO2 Hole‐Transporting Layer for Efficient and Photostable Perovskite Solar Cells
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Hua Zhang Huan Wang Hongmei Zhu Chu‐Chen Chueh Wei Chen Shihe Yang Alex K.‐Y. Jen 《Liver Transplantation》2018,8(13)
Organic–inorganic hybrid perovskite solar cells (PVSCs) have become the front‐running photovoltaic technology nowadays and are expected to profoundly impact society in the near future. However, their practical applications are currently hampered by the challenges of realizing high performance and long‐term stability simultaneously. Herein, the development of inverted PVSCs is reported based on low temperature solution‐processed CuCrO2 nanocrystals as a hole‐transporting layer (HTL), to replace the extensively studied NiOx counterpart due to its suitable electronic structure and charge carrier transporting properties. A ≈45 nm thick compact CuCrO2 layer is incorporated into an inverted planar configuration of indium tin oxides (ITO)/c‐CuCrO2/perovskite/[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM)/bathocuproine (BCP)/Ag, to result in the high steady‐state power conversion efficiency of 19.0% versus 17.1% for the typical low temperature solution‐processed NiOx‐based devices. More importantly, the optimized CuCrO2‐based device exhibits a much enhanced photostability than the reference device due to the greater UV light‐harvesting of the CuCrO2 layer, which can efficiently prevent the perovskite film from intense UV light exposure to avoid associated degradation. The results demonstrate the promising potential of CuCrO2 nanocrystals as an efficient HTL for realizing high‐performance and photostable inverted PVSCs. 相似文献
12.
Achieving High Open‐Circuit Voltages up to 1.57 V in Hole‐Transport‐Material‐Free MAPbBr3 Solar Cells with Carbon Electrodes
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Yongqi Liang Yajuan Wang Cheng Mu Sen Wang Xinnan Wang Dongsheng Xu Licheng Sun 《Liver Transplantation》2018,8(4)
An open‐circuit voltage (Voc) of 1.57 V under simulated AM1.5 sunlight in planar MAPbBr3 solar cells with carbon (graphite) electrodes is obtained. The hole‐transport‐material‐free MAPbBr3 solar cells with the normal architecture (FTO/TiO2/MAPbBr3/carbon) show little hysteresis during current–voltage sweep under simulated AM1.5 sunlight. A solar‐to‐electricity power conversion efficiency of 8.70% is achieved with the champion device. Accordingly, it is proposed that the carbon electrodes are effective to extract photogenerated holes in MAPbBr3 solar cells, and the industry‐applicable carbon electrodes will not limit the performance of bromide‐based perovskite solar cells. Based on the analysis of the band alignment, it is found that the voltage (energy) loss across the interface between MAPbBr3 and carbon is very small compared to the offset between the valence band maximum of MAPbBr3 and the work function of graphite. This finding implies either Fermi level pinning or highly doped region inside MAPbBr3 layer exists. The band‐edge electroluminescence spectra of MAPbBr3 from the solar cells further support no back‐transfer pathways of electrons across the MAPbBr3/TiO2 interface. 相似文献
13.
Thin‐Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates
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Maxwell Zheng Hsin‐Ping Wang Carolin M. Sutter‐Fella Corsin Battaglia Shaul Aloni Xufeng Wang James Moore Jeffrey W. Beeman Mark Hettick Matin Amani Wei‐Tse Hsu Joel W. Ager Peter Bermel Mark Lundstrom Jr‐Hau He Ali Javey 《Liver Transplantation》2015,5(22)
The design and performance of solar cells based on InP grown by the nonepitaxial thin‐film vapor–liquid–solid (TF‐VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p‐InP absorber layer, n‐TiO2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p‐doping process for TF‐VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open‐circuit voltage (VOC) of 692 mV, short‐circuit current (JSC) of 26.9 mA cm?2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p‐InP. 相似文献
14.
Hussein Melhem Pardis Simon Layla Beouch Fabrice Goubard Mourad Boucharef Catherine Di Bin Yann Leconte Bernard Ratier Nathalie Herlin‐Boime Johann Bouclé 《Liver Transplantation》2011,1(5):908-916
A crucial issue regarding emerging nanotechnologies remains the up‐scaling of new functional nanostructured materials towards their implementation in high performance applications on a large scale. In this context, we demonstrate high efficiency solid‐state dye‐sensitized solar cells prepared from new porous TiO2 photoanodes based on laser pyrolysis nanocrystals. This strategy exploits a reduced number of processing steps as well as non‐toxic chemical compounds to demonstrate highly porous TiO2 films. The possibility to easily tune the TiO2 nanocrystal physical properties allows us to demonstrate all solid‐state dye‐sensitized devices based on a commercial benchmark materials (organic indoline dye and molecular hole transporter) presenting state‐of‐the‐art performance comparable with reference devices based on a commercial TiO2 paste. In particular, a drastic improvement in pore infiltration, which is found to balance a relatively lower surface area compared to the reference electrode, is evidenced using laser‐synthesized nanocrystals resulting in an improved short‐circuit current density under full sunlight. Transient photovoltage decay measurements suggest that charge recombination kinetics still limit device performance. However, the proposed strategy emphasizes the potentialities of the laser pyrolysis technique for up‐scaling nanoporous TiO2 electrodes for various applications, especially for solar energy conversion. 相似文献
15.
Xiaoyan Du Ole Lytken Manuela S. Killian Jiamin Cao Tobias Stubhan Mathieu Turbiez Patrik Schmuki Hans‐Peter Steinrück Liming Ding Rainer H. Fink Ning Li Christoph J. Brabec 《Liver Transplantation》2017,7(5)
Organic solar cells are promising in terms of full‐solution‐processing which enables low‐cost and large‐scale fabrication. While single‐junction solar cells have seen a boost in power conversion efficiency (PCE), multi‐junction solar cells are promising to further enhance the PCE. In all‐solution‐processed multi‐junction solar cells, interfacial losses are often encountered between hole‐transporting layer (HTL) and the active layers and therefore greatly limit the application of newly developed high‐performance donor and acceptor materials in multi‐junction solar cells. Here, the authors report on a systematic study of interface losses in both single‐junction and multi‐junction solar cells based on representative polymer donors and HTLs using electron spectroscopy and time‐of‐flight secondary ion mass spectrometry. It is found that a facile mixed HTL containing poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and MoO x nanoparticles successfully overcomes the interfacial losses in both single‐ and multi‐junction solar cells based on various active layers by reducing interface protonation, promoting better energy‐level alignment, and forming a dense and smooth layer. Solution‐processed single‐junction solar cells are demonstrated to reach the same performance as with evaporated MoO x (over 7%). Multi‐junction solar cells with polymers containing nitrogen atoms as the first layer and the mixed PEDOT:PSS and MoO x nanoparticles as hole extraction layer reach fill factor (FF) of over 60%, and PCE of over 8%, while the identical stack with pristine PEDOT:PSS or MoO x nanoparticles show FF smaller than 50% and PCE less than 5%. 相似文献
16.
Yan Jiang Mikas Remeika Zhanhao Hu Emilio J. Juarez‐Perez Longbin Qiu Zonghao Liu Taehoon Kim Luis K. Ono Dae‐Yong Son Zafer Hawash Matthew R. Leyden Zhifang Wu Lingqiang Meng Jinsong Hu Yabing Qi 《Liver Transplantation》2019,9(13)
An upscalable perovskite film deposition method combining raster ultrasonic spray coating and chemical vapor deposition is reported. This method overcomes the coating size limitation of the existing stationary spray, single‐pass spray, and spin‐coating methods. In contrast with the spin‐coating method (>90% Pb waste), negligible Pb waste during PbI2 deposition makes this method more environmentally friendly. Outstanding film uniformity across the entire area of 5 cm × 5 cm is confirmed by both large‐area compatible characterization methods (electroluminescence and scattered light imaging) and local characterization methods (atomic force microscopy, scanning electron microscopy, photoluminescence mapping, UV–vis, and X‐ray diffraction measurements on multiple sample locations), resulting in low solar cell performance decrease upon increasing device area. With the FAPb(I0.85Br0.15)3 (FA = formamidinium) perovskite layer deposited by this method, champion solar modules show a power conversion efficiency of 14.7% on an active area of 12.0 cm2 and an outstanding shelf stability (only 3.6% relative power conversion efficiency decay after 3600 h aging). Under continuous operation (1 sun light illumination, maximum power point condition, dry N2 atmosphere with <5% relative humidity, no encapsulation), the devices show high light‐soaking stability corresponding to an average T80 lifetime of 535 h on the small‐area solar cells and 388 h on the solar module. 相似文献
17.
Si‐Doped Cu(In,Ga)Se2 Photovoltaic Devices with Energy Conversion Efficiencies Exceeding 16.5% without a Buffer Layer
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Shogo Ishizuka Jiro Nishinaga Masayuki Iioka Hirofumi Higuchi Yukiko Kamikawa Takashi Koida Hajime Shibata Paul Fons 《Liver Transplantation》2018,8(11)
In this communication, novel and simplified structure Cu(In,Ga)Se2 (CIGS) solar cells, which nominally consist of only a CIGS photoabsorber layer sandwiched between back and front contact layers but yet demonstrate high photovoltaic efficiencies, are reported. To realize this accomplishment, Si‐doped CIGS films grown by the three‐stage coevaporation method, B‐doped ZnO transparent conductive oxide front contact layers deposited by chemical vapor deposition, and heat–light soaking treatments are used. Si‐doping of CIGS films is found to modify the film surfaces and grain boundary properties and also affect the alkali metal distribution profiles in CIGS films. These effects are expected to contribute to improvements in buffer‐free CIGS device performance. Heat–light soaking treatments, which are occasionally performed to improve conventional buffer‐based CIGS device performance, are found to be also effective in enhancing buffer‐free CIGS photovoltaic efficiencies. This result suggests that the mechanism behind the beneficial effects of heat–light soaking treatments originates from CIGS bulk issues and is independent of the buffer materials. Consequently, over 16.5% efficiencies, including an independently certified value, are demonstrated from completely buffer‐free CIGS photovoltaic devices. 相似文献
18.
Torben Daeneke Ze Yu George P. Lee Dongchuan Fu Noel W. Duffy Satoshi Makuta Yasuhiro Tachibana Leone Spiccia Amaresh Mishra Peter Bäuerle Udo Bach 《Liver Transplantation》2015,5(4)
Nickel oxide based p‐type dye‐sensitized solar cells (DSCs) are limited in their efficiencies by poor fill factors (FFs). This work explores the origins of this limitation. Transient absorption spectroscopy identifies fast recombination between the injected hole and the dye anion under applied load as one of the predominant reasons for the poor FF of NiO‐based DSCs. A reduced hole injection efficiency, ηINJ, under applied load is found to play an equally important role. Both, the dye regeneration yield, ΦREG, and ηINJ decrease by approximately 40%–50% when moving from short‐ to open‐circuit conditions. Spectroelectrochemical measurements reveal that the electrochromic properties of NiO are a further limiting factor for the device performance leading to variable light‐harvesting efficiencies, ηLH, under applied load. The peak light‐harvesting efficiency decreases from 63% at short circuit to 57% at 600 mV reducing the FF of NiO DSCs by 5%. This effect is expected to be more pronounced for future devices with higher operating voltages. Incident, photon‐to‐electron conversion efficiency front–back analysis at applied bias is utilized to characterize the interfacial charge recombination. It is found that the recombination between the injected hole and the redox mediator has a surprisingly small effect on the FF. 相似文献
19.
Titanium Dioxide Mesoporous Electrodes for Solid‐State Dye‐Sensitized Solar Cells: Cross‐Analysis of the Critical Parameters
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Silvia Colella Emanuele Orgiu Ingmar Bruder Andrea Liscio Vincenzo Palermo Bernd Bruchmann Paolo Samorì Peter Erk 《Liver Transplantation》2014,4(9)
We report a comparative study on the use of four different mesoporous titanium dioxide (TiO2) photo‐electrodes for the fabrication of solid‐state dye‐sensitized solar cells (sDSSCs). The photovoltaic parameters of the device correlate with several intrinsic properties of the film, based not only on its morphological features, as commonly considered in standard characterizations, but also on the transport and the electronic properties of the photo‐electrode. These properties differ significantly for TiO2 electrodes processed using different colloidal pastes, and are decisive for the photovoltaic efficiency, ranging from 3.7% up to 5.1%. In particular, the dielectric permittivity of each mesoporous layer (εeff) and the number of traps (Nt) determined by the space‐charge‐limited current (SCLC) theory are found to be a bottle‐neck for the charge transport, greatly influencing the fill factor (FF) and open circuit voltage (Voc) of the cells. In addition, a direct correlation between TiO2 surface potential with the Voc was established. Cross‐analysis of key macroscopic parameters of the films prior to integration in the devices, in particular focusing on the determination of the capacitance and surface potential shift of the TiO2 mesoporous anode, represents a straightforward yet powerful method to screen and select the most suitable TiO2 for applications in sDSSCs. 相似文献
20.
Xinbo Yang Erkan Aydin Hang Xu Jingxuan Kang Mohamed Hedhili Wenzhu Liu Yimao Wan Jun Peng Christian Samundsett Andres Cuevas Stefaan De Wolf 《Liver Transplantation》2018,8(20)
Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices. 相似文献