Diagnosis of Perovskite Solar Cells Through Absolute Electroluminescence-Efficiency Measurements

Two organic-inorganic halide CH₃NH₃PbI₃ perovskite solar cells prepared in the same experimental batch but having different power conversion efficiencies −18.46% and 17.15%—were investigated based on the absolute electroluminescence (EL) efficiency measurements and traditional I-V measurements. The possible factors that affect the power conversion efficiency were also investigated. Comparing the experimental I-V curves of the two solar cells, it was found that the short-circuit currents (J_sc) were nearly the same; however, the open-circuit voltages (V_oc) were markedly different. Moreover, the deduced I-V curves from the absolute EL efficiencies of the two solar cells, which were mainly affected by the material quality, were almost the same, proving that the device processing technology has a vital effect on V_oc.