Optimizing performance and durability of perovskite light-emitting diodes through crystal grain manipulation and defect mitigation

Abstract

Recent advancements in quasi-two-dimensional perovskite light-emitting diodes (PeLEDs) have garnered significant attention due to their attractive properties, including facile solution processability, tunable emission spectra, and cost effectiveness. However, a critical challenge hindering their performance remains the quality of the perovskite emitting layer. Morphological and structural imperfections such as pinholes and halide vacancies, can significantly impede the subsequent layer deposition, leading to the formation of leakage current pathways. Furthermore, these lattice defects often serve as non-radiative recombination centers, compromising the device's overall luminescence efficiency. This study presents a facile strategy to address these limitations by incorporating polyethylene oxide (PEO) and trimethylolpropane triacrylate (TMPTA) as additives within the perovskite precursor solution. The high viscosity of PEO effectively restricts the diffusion of perovskite precursor, leading to the formation of smaller and more uniform crystal grains. In addition, the C=O functional group in TMPTA interacts favorably with uncoordinated Pb²⁺ cations in perovskite, thereby suppressing non-radiative recombination processes. By meticulously optimizing the volume ratio of PEO and TMPTA additives, effective passivation of perovskite film defects and manipulation of crystal grain morphology are achieved, leading to a significant enhancement of the perovskite emitting layer quality. Consequently, the maximum current efficiency and external quantum efficiency of green light-emitting diodes reach 45.3 cd/A and 12.01 %, respectively. This work establishes a simple and effective methodology for fabricating efficient and stable PeLEDs.