Imaging the Photo-Induced Electronic Properties of Grain Size Evolution in Perovskite-based Solar Cell by Scanning Tunneling Microscopy

• Main Authors: Cheng, Ming-Chih, 鄭名志
• Other Authors: Chiu, Ya-Ping
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/21754841840687437802

碩士 === 國立臺灣師範大學 === 物理學系 === 104 === The recent studies show that intermixing quantum crystal PbS with the active light-absorber (〖CH〗_3 〖NH〗_3 〖PbI〗_(3-x) 〖Cl〗_x) film in perovskite solar cell enlarges the grain size, which can be exceeded to 4µm. The quantum crystal in perovskite increases not only power conversion efficiency over 17.4%, but also the diffusion length. In order to investigate the variation of the electronic properties of the perovskite solar cell film in dark and under illumination condition, scanning tunneling microscopy (STM) was utilized to study the topography images and localized electronic properties of the perovskite active light-absorber. In this work, the electronic dI/dV spectroscopy measurement of perovskite intermixing PbS in dark demonstrates n-type semiconductor behavior. Moreover, the increase of density of states at valence band of perovskite film reveals the augment of hole carrier concentration under illumination. The shift of electronic dI/dV spectroscopy of perovskite with PbS compared to that of the perovskite without PbS shows that the magnitude of carriers separation is associated with the grain size. Also the grain size enlarged is beneficial for power conversion efficiency (PCE).