Long Electron–Hole Diffusion Length in High‐Quality Lead‐Free Double Perovskite Films

• Published in: Advanced materials (Weinheim) Vol. 30; no. 20; pp. e1706246 - n/a
• Main Authors: Ning, Weihua, Wang, Feng, Wu, Bo, Lu, Jun, Yan, Zhibo, Liu, Xianjie, Tao, Youtian, Liu, Jun‐Ming, Huang, Wei, Fahlman, Mats, Hultman, Lars, Sum, Tze Chien, Gao, Feng
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2018
• Subjects: Carrier recombination; Diffusion length; double perovskite; Energy conversion efficiency; Film thickness; Grain boundaries; lead free; long diffusion length; Materials science; Optoelectronic devices; Perovskites; Photovoltaic cells; planar solar cell; Solar cells; Solar corona; Titanium dioxide; Toxicity; lead free; double perovskite; planar solar cell; long diffusion length
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.201706246

Developing environmentally friendly perovskites has become important in solving the toxicity issue of lead‐based perovskite solar cells. Here, the first double perovskite (Cs2AgBiBr6) solar cells using the planar structure are demonstrated. The prepared Cs2AgBiBr6 films are composed of high‐crystal‐quality grains with diameters equal to the film thickness, thus minimizing the grain boundary length and the carrier recombination. These high‐quality double perovskite films show long electron–hole diffusion lengths greater than 100 nm, enabling the fabrication of planar structure double perovskite solar cells. The resulting solar cells based on planar TiO2 exhibit an average power conversion efficiency over 1%. This work represents an important step forward toward the realization of environmentally friendly solar cells and also has important implications for the applications of double perovskites in other optoelectronic devices. Cs2AgBiBr6 films composed of high‐crystal‐quality grains with diameters equal to the film thickness are fabricated. These high‐quality double‐perovskite films show electron–hole diffusion lengths greater than 100 nm, enabling the fabrication of planar‐structure double‐perovskite solar cells with a maximum value of 1.22%.