Organometallic Halide Perovskites: Sharp Optical Absorption Edge and Its Relation to Photovoltaic Performance
Organometallic Halide Perovskites: Sharp Optical Absorption Edge and Its Relation to Photovoltaic Performance
复制标题
DOI：
10.1021/jz500279b
复制
发表时间：
2014-03-20
影响因子：
5.7
通讯作者：
Ballif, Christophe
中科院分区：
文献类型：
--
作者：
De Wolf, Stefaan;Holovsky, Jakub;Ballif, Christophe
基于有机金属卤化物钙钛矿吸收层的太阳能电池正在成为一种高性能光伏技术。利用高灵敏度的光热偏转和光电流光谱技术，在室温下测量了CH_3NH_3PbI_3钙钛矿薄膜的吸收光谱。我们发现一个高的吸收系数，特别是尖锐的发病。低于带隙，吸收是指数超过四十年的乌尔巴赫能量小至15毫电子伏，这表明一个有序的微观结构。没有发现深态的检测极限接近1 cm（-1）。这些结果证实了钙钛矿薄膜的优异电子特性，使钙钛矿太阳能电池的开路电压非常高。在有意的水分进入后，我们发现在低于2.4 eV的光子能量下的吸收强烈减少，这表明材料的组成发生了变化。
Solar cells based on organometallic halide perovskite absorber layers are emerging as a high-performance photovoltaic technology. Using highly sensitive photothermal deflection and photocurrent spectroscopy, we measure the absorption spectrum of CH3NH3PbI3 perovskite thin films at room temperature. We find a high absorption coefficient with particularly sharp onset. Below the bandgap, the absorption is exponential over more than four decades with an Urbach energy as small as 15 meV, which suggests a well-ordered microstructure. No deep states are found down to the detection limit of similar to 1 cm(-1). These results confirm the excellent electronic properties of perovskite thin films, enabling the very high open-circuit voltages reported for perovskite solar cells. Following intentional moisture ingress, we find that the absorption at photon energies below 2.4 eV is strongly reduced, pointing to a compositional change of the material.