Research Abstract


Two-step photon up-conversion solar cells

2017年4月6日 Nature Communications 8 : 14962 doi: 10.1038/ncomms14962



Shigeo Asahi, Haruyuki Teranishi, Kazuki Kusaki, Toshiyuki Kaizu and Takashi Kita

Corresponding Authors

喜多 隆
神戸大学大学院 工学研究科 電子工学専攻

朝日 重雄
神戸大学大学院 工学研究科 電子工学専攻

Reducing the transmission loss for below-gap photons is a straightforward way to break the limit of the energy-conversion efficiency of solar cells (SCs). The up-conversion of below-gap photons is very promising for generating additional photocurrent. Here we propose a two-step photon up-conversion SC with a hetero-interface comprising different bandgaps of Al0.3Ga0.7As and GaAs. The below-gap photons for Al0.3Ga0.7As excite GaAs and generate electrons at the hetero-interface. The accumulated electrons at the hetero-interface are pumped upwards into the Al0.3Ga0.7As barrier by below-gap photons for GaAs. Efficient two-step photon up-conversion is achieved by introducing InAs quantum dots at the hetero-interface. We observe not only a dramatic increase in the additional photocurrent, which exceeds the reported values by approximately two orders of magnitude, but also an increase in the photovoltage. These results suggest that the two-step photon up-conversion SC has a high potential for implementation in the next-generation high-efficiency SCs.