Degradation of encapsulated perovskite solar cells driven by deep trap states and interfacial deterioration

Abstract

The degradation of encapsulated perovskite devices has been investigated by optoelectronic characterization. The performance of the encapsulated device dropped by approximately 50% of the initial value after five months. The degradation of device performance was found to be influenced by both interface recombination and deep trap assisted recombination in the perovskite. The analysis of temperature dependent current–voltage characteristics and capacitance spectra revealed that the decrease in the activation energy of interface recombination, deepening of the defect levels and reduction in the diffusion potential of devices led to deterioration of device parameters with aging. The degradation of the encapsulated device might be governed by dissociation and migration of constituent ions which induce deeper defect levels in the perovskite layer and deteriorate the interface with aging.