Characterization of Cu(In,Ga)Se_2 thin films by time-resolved photoluminescence

摘要

Cu(In,Ga)Se_2(CIGS) films were characterized by time-resolved photoluminescence (TRPL) on performances of solar cells. Open circuit voltage and efficiency of the solar cells increased with increasing the TRPL lifetimes meausred at 77 K and room temperature. The results at 77 K show that the CIGS films with the TRPL lifetime of over 30 ns achieve an efficiency of exceeding 15% of the solar cells. Dependence of the TRPL lifetime on the photon energy was observed on the CIGS film with high efficiency at both temperatures. This dependence is discussed on localization of exited carriers and non-radiative centres. The minority carrier lifetime which dominates the solar cell performances can be characterized by not only the TRPL lifetime but its dependence on the photon energy.