Li Jiang-Jun, Ma Jing-Yuan, Ge Qian-Qing, Hu Jin-Song, Wang Dong, Wan Li-Jun
Beijing National Laboratory for Molecular Science, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.
ACS Appl Mater Interfaces. 2015 Dec 30;7(51):28518-23. doi: 10.1021/acsami.5b09801. Epub 2015 Dec 15.
Grain boundaries (GBs) play an important role in organic-inorganic halide perovskite solar cells, which have generally been recognized as a new class of materials for photovoltaic applications. To definitely understand the electrical structure and behavior of GBs, here we present Kelvin probe force microscopy and conductive atomic force microscopy (c-AFM) measurements of both typical and inverted planar organolead halide perovskite solar cells. By comparing the contact potential difference (CPD) of these two devices in the dark and under illumination, we found that a downward band bending exists in GBs that predominantly attract photoinduced electrons. The c-AFM measurements observed that higher photocurrents flow through GBs when a low bias overcomes the barrier created by the band bending, indicating that GBs act as effective charge dissociation interfaces and photocurrent transduction pathways rather than recombination sites.
晶界在有机-无机卤化物钙钛矿太阳能电池中起着重要作用，这类电池通常被认为是用于光伏应用的一类新型材料。为了确切了解晶界的电学结构和行为，在此我们展示了对典型和倒置平面有机铅卤化物钙钛矿太阳能电池的开尔文探针力显微镜和导电原子力显微镜（c-AFM）测量。通过比较这两种器件在黑暗和光照条件下的接触电势差（CPD），我们发现晶界中存在向下的能带弯曲，其主要吸引光生电子。c-AFM测量观察到，当低偏压克服由能带弯曲产生的势垒时，更高的光电流会流经晶界，这表明晶界充当有效的电荷解离界面和光电流传导途径，而非复合位点。
