The Spacer Cations Interplay for Efficient and Stable Layered 2D Perovskite Solar Cells

【作者】 周宁； 张钰； 郭镇域； 刘少丞； 邱智文； 王峰； 周欢萍；

【机构】 北京大学工学院；

【摘要】 Organic spacer cations in layered 2 D（A1）₂（A2）_n-1BnX_3n+1（where A1 is an organic cation acting as a spacer between the perovskite layers,A2 is a monovalent cation,e.g.,Cs⁺,CH₃ NH3+,CH（NH₂）₂⁺） perovskite materials improve the long-term stability of the resulting solar cells,but hamper their power conversion efficiency due to poor carrier generation/transportation.Rational guidelines are thus required to enable the design of organic spacer cations.Herein,mixed A1 cations are employed in layered 2 D perovskites to investigate the interplay between alkylamine cations and unsaturated alkylamine cations.It is revealed that alkylamine spacer cations are able to facilitate precursor assembly,which results in the orientated growth of perovskite crystals.Unsaturated alkylamine cations further lead to reduced exciton binding energy,which improves carrier pathway in the 2 D perovskites.By mixing both cations,substantially improved open circuit voltage is observed in the resultant photovoltaic cells with the efficiency of 15.46%,one of the highest one based on（A1）₂（A2）₃ Pb₄I₁₃ layered 2 D perovskites.The generality of the design principle is further extended to other cation combinations.更多还原

【Abstract】 Organic spacer cations in layered 2 D（A1）₂（A2）_n-1BnX_3n+1（where A1 is an organic cation acting as a spacer between the perovskite layers,A2 is a monovalent cation,e.g.,Cs⁺,CH₃ NH3+,CH（NH₂）₂⁺） perovskite materials improve the long-term stability of the resulting solar cells,but hamper their power conversion efficiency due to poor carrier generation/transportation.Rational guidelines are thus required to enable the design of organic spacer cations.Herein,mixed A1 cations are employed in layered 2 D perovskites to investigate the interplay between alkylamine cations and unsaturated alkylamine cations.It is revealed that alkylamine spacer cations are able to facilitate precursor assembly,which results in the orientated growth of perovskite crystals.Unsaturated alkylamine cations further lead to reduced exciton binding energy,which improves carrier pathway in the 2 D perovskites.By mixing both cations,substantially improved open circuit voltage is observed in the resultant photovoltaic cells with the efficiency of 15.46%,one of the highest one based on（A1）₂（A2）₃ Pb₄I₁₃ layered 2 D perovskites.The generality of the design principle is further extended to other cation combinations.更多还原