Incident Light Intensity Dependences of Current Voltage Characteristics for Amorphous Silicon pin Solar Cells

비정질실리콘 pin태양전지에서 입사광 세기에 따른 전류 저압특성

The dependence of the current-voltage characteristics of hydrogenated amorphous silicon pin solar cells on the illumimination light intensity has been investigated. The open circuit voltage increases linearly with increasing the logarithm of light intensity up to AM 1, and nearly saturates above AM 1, indicating the open circuit voltage approaching the built-in potential of the pin solar cell above AM 1. The short circuit current density increase with light intensity in proportion to I**0.85 before and I**0.97 after light exposure. Since the series resistance devreses and shunt resistance increases with light intensily, the fill factor increases with light illumination. To increase the fill factor at high illumination in large area solar cells, t6he grid pattern on the ITO substrates should be made. Long light exposure on the solar cells gives rise to the increase of bulk resistance and defect states, resulting in the decrease of the fil factor and short circuit current density. The potential drop in the bulk of the a-Si:H pin solar cells at short circuit condition increases with decreasing temperature, and increases after long light exposure.