Charge Carrier Transport Properties in n = 1 Ruddlesden Popper Phase Perovskite

Abstract

The environmental impacts of current energy sources like fossil fuels has augmented the need for clean, renewable energy sources. Over the last 12 years, organic-inorganic crystalline perovskite materials have garnered the attention of the PV research community due to their remarkable device efficiency improvement from 3.8% to 25.2%. However, the environmental stability of metal halide perovskites poses a significant barrier to their deployment in PV technology. 2D Metal Halide Ruddlesden-Popper Phase perovskites have demonstrated improved ambient stability but their efficiencies are behind those of their 3D counterparts. Herein, we propose an investigation of the charge carrier transport in the planes of n = 1 Ruddlesden-Popper phase BA2PbI4 and BA2PbBr4 to provide insights into fundamental properties impacting their efficiencies. We begin by optimizing the deposition process of n = 1 BA2PbI4 thin films by altering 1) the presence of antisolvent and 2) the antisolvent deposition time. We determine that the incorporation of antisolvent in the deposition process improves the film quality which is quantified by the mitigation of holes in the thin films. We characterize the films through a combination of X-Ray diffraction, scanning electron microscopy, focused ion beam scanning electron microscopy and UV-Vis spectroscopy. We perform variable temperature current-voltage measurements from which we can extract the conductivity as a function of temperature and calculate the activation energy. We also perform the variable temperature current-voltage measurements in the dark and under illumination to investigate the effect on the conductivity.