基于不同电压下的电致发光和红外成像的太阳能电池缺陷检测

Abstract

The electroluminescence and infrared thermography were used to detect the defects of the solar cells by applying different forward bias and reverse bias voltage. The solar cell under forward bias mainly emits infrared light from 850 to 1 200 nm due to the recombination of electron and hole.The intensity of the emitted light depends on the series resistance and minority carrier diffusion length of the solar cell,so it can be used to detect the defects of finger disturbing,crack,and electrode etching,et al. The emission of light under reverse bias is intra-band emission which covers a wide spectrum from visible light to IR. The breakdown can be detected by reverse bias electroluminescence( RBEL). Only under high bias,weak Ohmic shunt appears in RBEL. Linear and nonlinear shunt can be detected using IR thermography under different bias. Strong Ohimc shunt can be detected in forward and reverse bias. The nonlinear shunt depends on the type.