Improving Device-to-Device Reproducibility of Light-Emitting Diodes Based on Layered Halide Perovskites

Abstract

Layered halide perovskites have emerged as a promising contender in solid-state lighting; however, the fabrication of perovskite light-emitting devices in laboratories usually experiences low device-to-device reproducibility since perovskite crystallization is highly sensitive to ambient conditions. Although device processing inside gloveboxes is primarily used to reduce the influence of oxygen and moisture, several extraneous variables, including thermal fluctuations in the inert atmosphere or contaminations from residual solvents, can destabilize the crystallization process and alter the properties of the emissive layers. Here, we examine typical experimental configurations used in research laboratories to deposit layered perovskite films in inert atmospheres and discuss their crucial influences on the formation of polycrystalline thin films. Our results demonstrate that fluctuations in the glovebox properties (concentrations of residual O2 and H2O or solvent traces), even in very short timescales, can negatively impact the consistency of the perovskite film formation, while thermal variation plays a relatively minor role in this phenomenon. Furthermore, the careful storage of chemical species inside the workstation is critical for reproducing high-quality perovskite layers. Consequently, when applying our most controlled environment for perovskite deposition, the photoluminescence lifetime of perovskite thin films shows a standard deviation of only 3%, whereas the reference set-up yields a 15% standard deviation. Regarding complete perovskite light-emitting diodes, the uncertainties in statistical luminance and EQE data are significantly reduced from 230% and 140% to 38% and 42%, respectively.