College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China.
State Key Laboratory of Space Power Technology, Shanghai Institute of Space Power Sources, Shanghai, 200245, P. R. China.
Adv Sci (Weinh). 2023 Jan;10(2):e2204058. doi: 10.1002/advs.202204058. Epub 2022 Nov 17.
Despite the fascinating optoelectronic properties of graphene, the power conversion efficiency (PCE) of graphene based solar cells remains to be lifted up. Herein, it is experimentally shown that the graphene/quantum wells/GaAs heterostructure solar cell can reach a PCE of 20.2% and an open-circuit voltage (V ) as high as 1.16 V at 90 K. The high efficiency is a result of carrier multiplication (CM) effect of graphene in the graphene/GaAs heterostructure. Especially, the external quantum efficiency (EQE) in the ultraviolet wavelength can be improved up to 72.2% based on the heterostructure constructed by graphene/In Ga As/GaAs P quantum wells/GaAs. The EQE increases as the light wavelength decreases, which indicates more carriers can be effectively excited by the higher energy photons through CM effect. Owing to these physical characters, the graphene/GaAs heterostructure solar cell will provide a possible way to exceed Shockley-Queisser (S-Q) limit.
尽管石墨烯具有迷人的光电性能，但基于石墨烯的太阳能电池的能量转换效率（PCE）仍有待提高。本文通过实验表明，石墨烯/量子阱/砷化镓异质结太阳能电池在 90 K 时的能量转换效率可达到 20.2%，开路电压（V）高达 1.16 V。这种高效率是石墨烯在石墨烯/砷化镓异质结中产生的载流子倍增（CM）效应的结果。特别是，基于石墨烯/InGaAs/砷化镓 P 量子阱/砷化镓构建的异质结，其紫外波长的外量子效率（EQE）可提高至 72.2%。EQE 随着光波长的减小而增加，这表明更多的载流子可以通过 CM 效应有效地被更高能量的光子激发。由于这些物理特性，石墨烯/砷化镓异质结太阳能电池将为超越肖克利-奎塞尔（S-Q）极限提供一种可能的途径。
