带隙
半导体
量子效率
材料科学
钙钛矿(结构)
卤化物
Crystal(编程语言)
直接和间接带隙
载流子
光电子学
凝聚态物理
化学
结晶学
物理
无机化学
计算机科学
程序设计语言
作者
Carolin M. Sutter‐Fella,David Miller,Quynh Phuong Ngo,Ellis T. Roe,Francesca M. Toma,Ian D. Sharp,Mark C. Lonergan,Ali Javey
出处
期刊:ACS energy letters
[American Chemical Society]
日期:2017-02-27
卷期号:2 (3): 709-715
被引量:103
标识
DOI:10.1021/acsenergylett.6b00727
摘要
Organometal halide perovskite semiconductors have emerged as promising candidates for optoelectronic applications because of the outstanding charge carrier transport properties, achieved with low-temperature synthesis. Here, we present highly sensitive sub-bandgap external quantum efficiency (EQE) measurements of Au/spiro-OMeTAD/CH3NH3Pb(I1–xBrx)3/TiO2/FTO/glass photovoltaic devices. The room-temperature spectra show exponential band tails with a sharp onset characterized by low Urbach energies (Eu) over the full halide composition space. The Urbach energies are 15–23 meV, lower than those for most semiconductors with similar bandgaps (especially with Eg > 1.9 eV). Intentional aging of CH3NH3Pb(I1–xBrx)3 for up to 2300 h, reveals no change in Eu, despite the appearance of the PbI2 phase due to decomposition, and confirms a high degree of crystal ordering. Moreover, sub-bandgap EQE measurements reveal an extended band of sub-bandgap electronic states that can be fit with one or two point defects for pure CH3NH3PbI3 or mixed CH3NH3Pb(I1–xBrx)3 compositions, respectively. The study provides experimental evidence of defect states close to the midgap that could impact photocarrier recombination and energy conversion efficiency in higher bandgap CH3NH3Pb(I1–xBrx)3 alloys.
科研通智能强力驱动
Strongly Powered by AbleSci AI