Light-Induced Increase of Electron Diffusion Length in a p鈥搉 Junction Type CH3NH3PbBr3 Perovskite Solar Cell

详细信息    查看全文

• 作者：Nir Kedem ; Thomas M. Brenner ; Michael Kulbak ; Norbert Schaefer ; Sergiu Levcenko ; Igal Levine ; Daniel Abou-Ras ; Gary Hodes ; David Cahen
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：6
• 期：13
• 页码：2469-2476
• 全文大小：367K
• ISSN：1948-7185

文摘

High band gap, high open-circuit voltage solar cells with methylammonium lead tribromide (MAPbBr<sub>3sub>) perovskite absorbers are of interest for spectral splitting and photoelectrochemical applications, because of their good performance and ease of processing. The physical origin of high performance in these and similar perovskite-based devices remains only partially understood. Using cross-sectional electron-beam-induced current (EBIC) measurements, we find an increase in carrier diffusion length in MAPbBr<sub>3sub>(Cl)-based solar cells upon low intensity (a few percent of 1 sun intensity) blue laser illumination. Comparing dark and illuminated conditions, the minority carrier (electron) diffusion length increases about 3.5 times from L<sub>nsub> = 100 卤 50 nm to 360 卤 22 nm. The EBIC cross section profile indicates a p鈥搉 structure between the n-FTO/TiO<sub>2sub> and p-perovskite, rather than the p鈥搃鈥搉 structure, reported for the iodide derivative. On the basis of the variation in space-charge region width with varying bias, measured by EBIC and capacitance鈥搗oltage measurements, we estimate the net-doping concentration in MAPbBr<sub>3sub>(Cl) to be 3鈥? 脳 10<sup>17sup> cm<sup>鈥?sup>.