Strong voltage-boost effect in two-step photon-up conversion solar cells
Shigeo Asahi& Takashi Kita
Kobe University, Kobe, Japan

We recently have proposed an SC structure called two-step photon up-conversion solar cell (TPU-SC). In this solar cell, we have observed a clear enhancement in the open-circuit voltage as well as in the short-circuit voltage. In this study, we investigated the excitation intensity dependence of the TPU. We find that the photocurrent increase due to the TPU has a sub-linear relationship between the interband excitation intensity. In addition, the observed value of the increase in the open-circuit voltage by the TPU is larger than that of the estimated value, which is estimated from the short-circuit voltage and its increase by the TPU, suggesting voltage-boost occurs at the hetero-interface.