Back-contacted perovskite solar cells(PSCs)have been demonstrated with merits of low material cost and weak ion migration,while the inferior buried surface restricts their performance and bifacial response.Herein,poly...Back-contacted perovskite solar cells(PSCs)have been demonstrated with merits of low material cost and weak ion migration,while the inferior buried surface restricts their performance and bifacial response.Herein,polyvinylidene fluoride(PVDF)with similar thermal expansion coefficient to perovskites and low tensile modulus is introduced at the substrate/crystal interface to release interface lattice strain and enhance crystallinity.Besides,PVDF can release free fluoride ions to interact with bare Pb^(2+)ions,reducing interface charge trap density and nonradiative recombination.As a result,an impressive efficiency of 13.37%is obtained,setting a new efficiency benchmark for back-contacted PSCs.Moreover,the PVDF-modified devices retain 100%of their initial efficiency after 1,200 h of maximum power point tracking at 60℃.Finally,a high bifaciality factor of 0.96 is obtained,leading to obvious increase of power output under simulated circumstance with reflected light.展开更多
Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)presents a promising low-cost and sustainable photovoltaic material.However,its performance is critically hindered by uncontrollable complex crystallization during high-temperatur...Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)presents a promising low-cost and sustainable photovoltaic material.However,its performance is critically hindered by uncontrollable complex crystallization during high-temperature selenization and the detrimental formation of a MoSe_(2) back contact layer,which induces significant carrier recombination losses,imposing severe limitations on open-circuit voltage(VOC)and fill factor(FF).Addressing the challenge of achieving high-quality CZTSSe absorbers and interfaces,this study introduces a novel thermal modulation strategy during selenization.By optimizing nucleation and crystallization through a controlled slow heating stage—distinct from conventional sustained high-temperature processes—this method yields more uniform CZTSSe grains,effectively suppresses runaway growth of the interfacial MoSe_(2) layer,and inhibits absorber decomposition at the interface.Consequently,interface defect density is substantially reduced,leading to enhanced carrier transport properties.Devices fabricated using this method within the Cu^(2+)-Sn^(2+)-N,N-dimethylformamide(DMF)precursor system achieved a significant power conversion efficiency(PCE)increase from 8.02%to 11.65%,driven by a VOC rise from 409 to 489 mV and a substantial FF enhancement from 54.34%to 63.63%.Furthermore,the method demonstrates excellent process compatibility,achieving PCEs of 13.72%and 13.81%in Cu^(+)-Sn^(4+)-DMF and Cu^(+)-Sn^(4+)-methoxyethanol(MOE)systems,respectively.This work underscores the crucial importance of the CZTSSe/Mo interface and provides new insights and pathways for fabricating high-quality absorbers and efficient kesterite solar cells.展开更多
The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach th...The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach the theoretical efficiency limit of ~33.5%. The findings of this study are significant, from an efficiency standpoint, and also because the cell design can be realized using existing fabrication methods that do not require complex, post-processing steps. In this study, a benchmark simulation is developed that closely resembles a high-efficiency, front-and-back contact cell. Intrinsic performance limiters are overcome by moving the emitter and front-contact to the back of the cell to eliminate electrical grid shading and improve optical performance. To further improve performance, the P-N junction formed by the emitter layer is removed from the model to allow selective Ohmic contacts to accept (reject) minority (majority) carriers as required. The design modifications improve open-circuit voltage, short-circuit current, and fill-factor which collectively boost efficiency above 30%-primarily due to a 2% gain of incident irradiance and improved optical performance.展开更多
This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conve...This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conversion efficiency. Key design parameters are optimized under an Air-Mass (AM) 1.5 spectrum to improve performance and approach the 33.5% theoretical efficiency limit. A second optimization is performed under an AM0 spectrum to examine the cell’s potential for space applications. This research demonstrates the feasibility and potential of a new thin-film solar cell design for terrestrial and space applications. Results suggest that the straight-forward design may be an inexpensive alternative to multi-junction solar cells.展开更多
ZnTe/ZnTe:Cu complex layers deposited by vacuum co-evaporation have been in- troduced to CdS/CdTe solar cells. The C-V and I-V curves have been investigated and the effects of un-doped ZnTe layer thickness as well as ...ZnTe/ZnTe:Cu complex layers deposited by vacuum co-evaporation have been in- troduced to CdS/CdTe solar cells. The C-V and I-V curves have been investigated and the effects of un-doped ZnTe layer thickness as well as annealing temperatures on I-V characteristics of CdTe solar cells have been studied. The results show that the “roll over” and “cross over” phenomena of dark and light I-V curves can be eliminated by use of ZnTe/ZnTe:Cu layer and the fill factor for a typical sample has increased to 73%, where there is no high resistance transparent layer. The reasons have been discussed combined with the energy band diagram of CdTe solar cells.展开更多
In this viewpoint,recent hot topics in the photovoltaic community,interdigitated back contact(IBC)cells,are systematically reviewed from the view of device configuration.Two categories of IBC designs on the most popul...In this viewpoint,recent hot topics in the photovoltaic community,interdigitated back contact(IBC)cells,are systematically reviewed from the view of device configuration.Two categories of IBC designs on the most popular perovskite solar cells(PSCs)were discussed,and a planar back-contact perovskite module was first proposed.The device configuration,fabrication methods,working mechanism,optimization strategies,and future development directions of this novel PSC module were put forward to show its superiorities in the module performance,processing difficulty,and extensible functionality among present perovskite modules,presenting promising potential to improve the competitiveness of perovskite technology in the photovoltaic market.展开更多
基金economically supported by the National Natural Science Foundation of China(62474102)Key R&D Program of Shandong Province,China(2024CXGC010302)。
文摘Back-contacted perovskite solar cells(PSCs)have been demonstrated with merits of low material cost and weak ion migration,while the inferior buried surface restricts their performance and bifacial response.Herein,polyvinylidene fluoride(PVDF)with similar thermal expansion coefficient to perovskites and low tensile modulus is introduced at the substrate/crystal interface to release interface lattice strain and enhance crystallinity.Besides,PVDF can release free fluoride ions to interact with bare Pb^(2+)ions,reducing interface charge trap density and nonradiative recombination.As a result,an impressive efficiency of 13.37%is obtained,setting a new efficiency benchmark for back-contacted PSCs.Moreover,the PVDF-modified devices retain 100%of their initial efficiency after 1,200 h of maximum power point tracking at 60℃.Finally,a high bifaciality factor of 0.96 is obtained,leading to obvious increase of power output under simulated circumstance with reflected light.
基金supported by the National Natural Science Foundation of China(Nos.62064010 and 62104120)Industrial Technology Innovation Projects of Inner Mongolia Academy of Science and Technology of China(No.2023JSYD01002)+1 种基金Science and Technology Plan Projects of Inner Mongolia Autonomous Region of China(Nos.2023KYPT0012,2023YFHH0061,2024YFKL0002,and 2023YFHH0049)the Hohhot Science and Technology Project(Nos.2024-JBGS-G-1 and 2024-JBGS-G-2).
文摘Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)presents a promising low-cost and sustainable photovoltaic material.However,its performance is critically hindered by uncontrollable complex crystallization during high-temperature selenization and the detrimental formation of a MoSe_(2) back contact layer,which induces significant carrier recombination losses,imposing severe limitations on open-circuit voltage(VOC)and fill factor(FF).Addressing the challenge of achieving high-quality CZTSSe absorbers and interfaces,this study introduces a novel thermal modulation strategy during selenization.By optimizing nucleation and crystallization through a controlled slow heating stage—distinct from conventional sustained high-temperature processes—this method yields more uniform CZTSSe grains,effectively suppresses runaway growth of the interfacial MoSe_(2) layer,and inhibits absorber decomposition at the interface.Consequently,interface defect density is substantially reduced,leading to enhanced carrier transport properties.Devices fabricated using this method within the Cu^(2+)-Sn^(2+)-N,N-dimethylformamide(DMF)precursor system achieved a significant power conversion efficiency(PCE)increase from 8.02%to 11.65%,driven by a VOC rise from 409 to 489 mV and a substantial FF enhancement from 54.34%to 63.63%.Furthermore,the method demonstrates excellent process compatibility,achieving PCEs of 13.72%and 13.81%in Cu^(+)-Sn^(4+)-DMF and Cu^(+)-Sn^(4+)-methoxyethanol(MOE)systems,respectively.This work underscores the crucial importance of the CZTSSe/Mo interface and provides new insights and pathways for fabricating high-quality absorbers and efficient kesterite solar cells.
文摘The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach the theoretical efficiency limit of ~33.5%. The findings of this study are significant, from an efficiency standpoint, and also because the cell design can be realized using existing fabrication methods that do not require complex, post-processing steps. In this study, a benchmark simulation is developed that closely resembles a high-efficiency, front-and-back contact cell. Intrinsic performance limiters are overcome by moving the emitter and front-contact to the back of the cell to eliminate electrical grid shading and improve optical performance. To further improve performance, the P-N junction formed by the emitter layer is removed from the model to allow selective Ohmic contacts to accept (reject) minority (majority) carriers as required. The design modifications improve open-circuit voltage, short-circuit current, and fill-factor which collectively boost efficiency above 30%-primarily due to a 2% gain of incident irradiance and improved optical performance.
文摘This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conversion efficiency. Key design parameters are optimized under an Air-Mass (AM) 1.5 spectrum to improve performance and approach the 33.5% theoretical efficiency limit. A second optimization is performed under an AM0 spectrum to examine the cell’s potential for space applications. This research demonstrates the feasibility and potential of a new thin-film solar cell design for terrestrial and space applications. Results suggest that the straight-forward design may be an inexpensive alternative to multi-junction solar cells.
基金Supported by the National High Technology ResearchDevelopment Program (863 Program)the Tenth Five-year Plan of China (Grant No. 2003AA513010)
文摘ZnTe/ZnTe:Cu complex layers deposited by vacuum co-evaporation have been in- troduced to CdS/CdTe solar cells. The C-V and I-V curves have been investigated and the effects of un-doped ZnTe layer thickness as well as annealing temperatures on I-V characteristics of CdTe solar cells have been studied. The results show that the “roll over” and “cross over” phenomena of dark and light I-V curves can be eliminated by use of ZnTe/ZnTe:Cu layer and the fill factor for a typical sample has increased to 73%, where there is no high resistance transparent layer. The reasons have been discussed combined with the energy band diagram of CdTe solar cells.
基金China Postdoctoral Science Foundation(2023M731476,2023T160286)Beijing Postdoctoral Research Foundation.
文摘In this viewpoint,recent hot topics in the photovoltaic community,interdigitated back contact(IBC)cells,are systematically reviewed from the view of device configuration.Two categories of IBC designs on the most popular perovskite solar cells(PSCs)were discussed,and a planar back-contact perovskite module was first proposed.The device configuration,fabrication methods,working mechanism,optimization strategies,and future development directions of this novel PSC module were put forward to show its superiorities in the module performance,processing difficulty,and extensible functionality among present perovskite modules,presenting promising potential to improve the competitiveness of perovskite technology in the photovoltaic market.
