Understanding Temperature‐Dependent Charge Extraction and Trapping in Perovskite Solar Cells
Qian Zhou, Boxing Wang, Rui Meng, Jiyu Zhou, Shenkun Xie, Xuning Zhang, Jianqiu Wang, Shengli Yue, Bing Qin, Huiqiong Zhou, Yuan Zhang
Abstract
Abstract Understanding the factors that limit the performance of perovskite solar cells (PSCs) can be enriched by detailed temperature ( T )‐dependent studies. Based on p‐i‐n type PSCs with prototype methylammonium lead triiodide (MAPbI 3 ) perovskite absorbers, T ‐dependent photovoltaic properties are explored and negative T ‐coefficients for the three device parameters ( V OC , J SC , and FF) are observed within a wide low T ‐range, leading to a maximum power conversion efficiency (PCE) of 21.4% with an impressive fill factor (FF) approaching 82% at 220 K. These T ‐behaviors are explained by the enhanced interfacial charge transfer, reduced charge trapping with suppressed nonradiative recombination and narrowed optical bandgap at lower T . By comparing the T ‐dependent device behaviors based on MAPbI 3 devices containing a PASP passivation layer, enhanced PCE at room temperature is observed but different tendencies showing attenuating T ‐dependencies of J SC and FF, which eventually leads to nearly T ‐invariable PCEs. These results indicate that charge extraction with the utilized all‐organic charge transporting layers is not a limiting factor for low‐ T device operation, meanwhile the trap passivation layer of choice can play a role in the T ‐dependent photovoltaic properties and thus needs to be considered for PSCs operating in a temperature‐variable environment.