A mini-review of PEDOT:PSS hole-transporting layer engineering for perovskite light-emitting diode applications

Abstract

Perovskites represent a class of next-generation emitters for light-emitting diode applications. They are typically deposited onto a hole-transporting layer (HTL) of poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). Although this HTL offers advantages such as solution processability and high optical transparency, it suffers from intrinsic drawbacks, including mismatched energy levels, strong acidity, hygroscopicity, and interfacial defects. Consequently, perovskite light-emitting diodes (PeLEDs) that employ PEDOT:PSS HTLs generally exhibit inferior performance and stability compared to devices based on inorganic HTLs. To address these limitations, this review systematically advances the understanding of PEDOT:PSS engineering toward high-performance PeLEDs. We begin by discussing the working mechanism of PeLEDs, followed by the fundamental properties of PEDOT:PSS and its associated drawbacks in PeLEDs. We then summarize recent device engineering strategies for PEDOT:PSS-based PeLEDs, categorizing them into bulk engineering and interface engineering. Finally, we discuss critical future research directions, with the goal of guiding the development of PEDOT:PSS-based PeLEDs.