材料科学
光电流
光电子学
电子转移
量子效率
激发
红外线的
光电效应
电子
分子物理学
光学
光化学
化学
物理
量子力学
作者
Yuanfang Yu,Lei Gao,Xianghong Niu,Kaiyang Liu,Ruizhi Li,Dandan Yang,Haibo Zeng,Hui‐Qiong Wang,Zhenhua Ni,Junpeng Lü
标识
DOI:10.1002/adma.202210157
摘要
Hot-carrier devices are promising alternatives for enabling path breaking photoelectric conversion. However, existing hot-carrier devices suffer from low efficiencies, particularly in the infrared region, and ambiguous physical mechanisms. In this work, the competitive interfacial transfer mechanisms of detrapped holes and hot electrons in hot-carrier devices are discovered. Through photocurrent polarity research and optical-pump-THz-probe (OPTP) spectroscopy, it is verified that detrapped hole transfer (DHT) and hot-electron transfer (HET) dominate the low- and high-density excitation responses, respectively. The photocurrent ratio assigned to DHT and HET increases from 6.6% to over 1133.3% as the illumination intensity decreases. DHT induces severe degeneration of the external quantum efficiency (EQE), especially at low illumination intensities. The EQE of a hot-electron device can theoretically increase by over two orders of magnitude at 10 mW cm-2 through DHT elimination. The OPTP results show that competitive transfer arises from the carrier oscillation type and carrier-density-related Coulomb screening. The screening intensity determines the excitation weight and hot-electron cooling scenes and thereby the transfer dynamics.
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