Here in this paper, we demonstrate a facile technique for creating the mixed formamidinium（HN = CHNH_3~＋, FA~＋）and methylammonium（CH_3NH_3~＋, MA~＋） cations in the lead iodide perovskite. This technique entails...Here in this paper, we demonstrate a facile technique for creating the mixed formamidinium（HN = CHNH_3~＋, FA~＋）and methylammonium（CH_3NH_3~＋, MA~＋） cations in the lead iodide perovskite. This technique entails a facile drop-casting of formamidinium iodide（FAI） solutions on as-prepared MAPbI_3 perovskite thin films under the controlled conditions,which leads to controllable displacement of the MA~＋ cations by FA~＋ cations in the perovskite structure at room temperature. Uniform and controllable mixed organic cation perovskite thin films without a ＂bi-layered＂ or graded structure are achieved. By applying this approach to photovoltaic devices, we are able to improve the performances of devices through extending their optical-absorption onset further into the infrared region to enhance solar-light harvesting. Additionally,this work provides a simple and efficient technique to tune the structural, electrical, and optoelectronic properties of the light-harvesting materials for high-performance perovskite solar cells.展开更多
Monolithic perovskite/organic tandem solar cells(TsCs)have gained significant attention due to their easy device integration and the potential to surpass the Shockley-Queisser limit of single-junction solar cells.Howe...Monolithic perovskite/organic tandem solar cells(TsCs)have gained significant attention due to their easy device integration and the potential to surpass the Shockley-Queisser limit of single-junction solar cells.However,the surfaces of wide-bandgap perovskite films are densely populated with defects,leading to severe non-radiative recombination and energy loss.As a consequence,the power conversion efficiency(PCE)of perovskite/organic TSCs lags behind that of other TSC counterparts.To address these issues,we designed a functional ammonium salt,4-(2-hydroxyethyl)piperazin-1-ium iodide(Pzol),comprising a piperazine iodide and a terminated hydroxyl group,which was applied for post-treating the perovskite surface.Our findings reveal that Pzol reacts with and consumes residual PbX_(2)(X:I or Br)to form a 2D perovskite component,thereby eliminating Pb^(0)defects,while the terminated hydroxyl group in PZOI can also passivate uncoordinated Pb^(2+).Consequently,the shallow/deep-level defect densities of the 2D/3D perovskite film were significantly reduced,leading to an enhanced PCE of single-junction 2D/3D wide-bandgap perovskite solar cells to 18.18% with a reduced energy loss of 40 mev.Importantly,the corresponding perovskite/organic TSCs achieved a remarkable PCE of 24.05% with enhanced operational stability(T_(90)~500h).展开更多
Organohalogen perovskites are attracting con- siderable attention for use in solar cells. However, the stability of these devices will determine whether they can be made commercially viable. Device encapsulation or th...Organohalogen perovskites are attracting con- siderable attention for use in solar cells. However, the stability of these devices will determine whether they can be made commercially viable. Device encapsulation or the use of a hydrophobic hole-transporting material can pre- vent the permeation of water into the perovskite layer and enhance the humidity stability of the cells under dark conditions. With regard to the light stability of solar cells, recent studies have yielded contradictory results. This work investigated the degradation mechanism of perovskite solar cells under illumination. Further, a simple method was proposed for improving their illumination stability. Amino acids were inserted between the compact TiO2 layer and the perovskite layer to effectively prevent the decomposition of the perovskite layer owing to the superoxide anions and hydroxyl radicals generated under illumination from the H2O and O2 adsorbed onto the TiO2 layer.展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.2015QNA09)
文摘Here in this paper, we demonstrate a facile technique for creating the mixed formamidinium（HN = CHNH_3~＋, FA~＋）and methylammonium（CH_3NH_3~＋, MA~＋） cations in the lead iodide perovskite. This technique entails a facile drop-casting of formamidinium iodide（FAI） solutions on as-prepared MAPbI_3 perovskite thin films under the controlled conditions,which leads to controllable displacement of the MA~＋ cations by FA~＋ cations in the perovskite structure at room temperature. Uniform and controllable mixed organic cation perovskite thin films without a ＂bi-layered＂ or graded structure are achieved. By applying this approach to photovoltaic devices, we are able to improve the performances of devices through extending their optical-absorption onset further into the infrared region to enhance solar-light harvesting. Additionally,this work provides a simple and efficient technique to tune the structural, electrical, and optoelectronic properties of the light-harvesting materials for high-performance perovskite solar cells.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4200302)the National Natural Science Foundation of China(Grant Nos.52325307,52203233,22075194,and 52273188)+2 种基金Department of Science and Technology of Jiangsu Province(No.BE2022023)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Collaborative Innovation Center of Suzhou Nano Science and Technology,and the Key Laboratory of Polymeric Materials Design and Synthesis for Biomedical Function,Soochow University,Undergraduate Training Programfor Innovation and Entrepreneurship,Soochow University(No.202310285036Z).
文摘Monolithic perovskite/organic tandem solar cells(TsCs)have gained significant attention due to their easy device integration and the potential to surpass the Shockley-Queisser limit of single-junction solar cells.However,the surfaces of wide-bandgap perovskite films are densely populated with defects,leading to severe non-radiative recombination and energy loss.As a consequence,the power conversion efficiency(PCE)of perovskite/organic TSCs lags behind that of other TSC counterparts.To address these issues,we designed a functional ammonium salt,4-(2-hydroxyethyl)piperazin-1-ium iodide(Pzol),comprising a piperazine iodide and a terminated hydroxyl group,which was applied for post-treating the perovskite surface.Our findings reveal that Pzol reacts with and consumes residual PbX_(2)(X:I or Br)to form a 2D perovskite component,thereby eliminating Pb^(0)defects,while the terminated hydroxyl group in PZOI can also passivate uncoordinated Pb^(2+).Consequently,the shallow/deep-level defect densities of the 2D/3D perovskite film were significantly reduced,leading to an enhanced PCE of single-junction 2D/3D wide-bandgap perovskite solar cells to 18.18% with a reduced energy loss of 40 mev.Importantly,the corresponding perovskite/organic TSCs achieved a remarkable PCE of 24.05% with enhanced operational stability(T_(90)~500h).
文摘Organohalogen perovskites are attracting con- siderable attention for use in solar cells. However, the stability of these devices will determine whether they can be made commercially viable. Device encapsulation or the use of a hydrophobic hole-transporting material can pre- vent the permeation of water into the perovskite layer and enhance the humidity stability of the cells under dark conditions. With regard to the light stability of solar cells, recent studies have yielded contradictory results. This work investigated the degradation mechanism of perovskite solar cells under illumination. Further, a simple method was proposed for improving their illumination stability. Amino acids were inserted between the compact TiO2 layer and the perovskite layer to effectively prevent the decomposition of the perovskite layer owing to the superoxide anions and hydroxyl radicals generated under illumination from the H2O and O2 adsorbed onto the TiO2 layer.
