Enhanced performance of solution-processed organic light-emitting diodes with TEMPOL derivatives

Abstract

This study reports novel solution-processed 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL)-derivative organic compounds in a widely employed hole-injection/transport poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) layer. The TEMPOL-derived organic dopants, synthesized via a one-step chemical procedure, exhibited distinctive molecular dipole characteristics and electrical conductivities. The green organic light-emitting diodes (OLEDs) with a 4-benzene sulfonyl-2,2,6,6-tetramethyl-1-piperidenyloxy radical (TBS)-doped PEDOT:PSS layer exhibited a maximum power efficiency (PEmax) of 25.58 lm W−1, maximum external quantum efficiency (EQEmax) of 12.19 %, and maximum current efficiency (CEmax) of 40.85 cd A−1, demonstrating significant improvements compared with the pristine PEDOT:PSS layer-based device. The PEmax (16.18 lm W−1), EQEmax (10.67 %), and CEmax (37.01 cd A−1) were obtained with fiber OLEDs under same conditions. This enhancement in OLED performance can be attributed to the decreased hole-injection barrier at the anode and emissive layer interfaces. © 2024 Elsevier B.V.