Abstract
Heterojunction photovoltaic cells were fabricated with composite materials of TiO2 encapsulated in polymetylmethacrylate and p-type silicon (C-PMMA-TiO2/p-Si), and with TiO2 and p-Si (TiO2/p-Si), respectively, and their electrical and photovoltaic characteristics were investigated. As a result, the dark current vs. voltage characteristics indicated good rectification for the both cells. The rectification ratios were about 11 and 34 at 0.4V for TiO2/p-Si and C-PMMA-TiO2/p-Si heterojunction photovoltaic cells, respectively. However, the open-circuit voltage and the short-circuit current density of TiO2/p-Si heterojunction photovoltaic cell under light irradiation were extremely smaller than those of C-PMMA-TiO2/p-Si heterojunction photovoltaic cell. Under the light irradiation of wavelength 525nm with the intensity of 80μW/cm2, the photovoltaic properties of C-PMMA-TiO2/p-Si heterojunction photovoltaic cell were as follows: the open-circuit voltage Voc is 0.25V, the shortcircuit current density Jsc is 3.0μA/cm2, the fill factor F.F is 0.59 and the power conversion efficiency is 1.3%. Furthermore, the dark current vs. voltage and capacitance vs. voltage characteristics on C-PMMA-TiO2/p-Si heterojunction photovoltaic cell were studied, and the transport mechanisms were discussed.
