High-performance and high-durability perovskite photovoltaic devices prepared using ethylammonium iodide as an additive

Abstract

In this study, we determined that the film morphologies, crystallinities, and optical properties of CH₃NH₃PbI_3−xCl_x perovskite (PVSK) layers can be manipulated by incorporating a small amount of ethylammonium iodide (EAI) into the perovskite precursor solution. For our EAI-derived films, we observed higher absorbances at higher wavelengths and higher degrees of crystallinity, both of which were associated with the higher surface coverage of the PVSK films. The optimized power conversion efficiency (PCE) improved from 9.4 ± 0.76 to 10.2 ± 0.58% after the addition of 0.5 vol% of EAI. Devices based on EAI-containing PVSK exhibited extremely high stability, retaining approximately 80% of their PCEs (T₈₀) under accelerated heating (65 °C) in a dark N₂-filled glove box for over 360 h. In contrast, the corresponding normal device was relatively sensitive to this temperature, with a T₈₀ value of only 45 h. The improved device performance (PCE, stability) arose as a result of the presence of EAI suppressing the crystallization of CH₃NH₃PbI_3−xCl_x.