Temperature-Dependent Electroluminescence from CdTe/CdS solar cells

摘要

Electroluminescence (EL) from polycrystalline CdTe/CdS solar cells was studied over the temperature range - 30 C to 25 C. We are able to observe above-background EL at forward current densities as low as 3 mA/cm{sup}2, allowing us to explore the EL behavior at current-voltage regimes within the normal operating parameters of the device. The EL spectrum is very similar to the photoluminescence (PL) spectrum, and is independent of applied voltage. We show that the EL most likely originates from injected electron-hole recombination at the CdTe/CdS junction. The total EL intensity is found to vary as a power-law function of current, EL ～ I{sup}b, where I is the forward current density and b is a constant. The value of b varies from sample to sample and decreases with increasing temperature. EL intensity typically is much more sensitive to device deterioration with light soak stress than is cell efficiency.