Exploring Cs 2 AgBiBr 6 halide double perovskite as a lead-free emissive material for perovskite LEDs

Abstract Numerical simulations were performed to evaluate the suitability of cesium silver bismuth bromide (Cs 2 AgBiBr 6 ) halide double perovskite as an efficient emissive layer (EML) for perovskite-based LEDs (PeLEDs). The study investigates various hole-injection layer (HIL) materials, revealing their substantial impact on device performance. Hole mobility and energy barriers at the metal/HIL and HIL/EML interfaces are identified as key determinants of optoelectronic efficiency. Among the tested HILs, Cu 2 O delivered the best performance, achieving a maximum EQE of 27.36% and current efficiency (CE) of 51.84 cd A −1 , followed by NiO (EQE: 9.81%, CE: 47.32 cd A −1 ) and CBTS (EQE: 1.14%, CE: 3.96 cd A −1 ), owing to its high hole mobility and balanced carrier injection. HIL thickness was found to have negligible influence on PeLEDs characteristics. Doping-dependent analysis shows that PeLEDs performance declines gradually with acceptor concentration up to 10 18 cm −3 but deteriorates sharply beyond this point, while donor doping enhances performance up to 10 19 cm −3 before Auger recombination becomes dominant. These trends are mainly ascribed to shifts in the recombination zone with doping variation. Additionally, increasing defect density markedly reduces luminance and current efficiency due to enhanced Shockley–Read–Hall (SRH) recombination, which lowers IQE and EQE by promoting non-radiative pathways over radiative recombination. This work provides valuable insights to strengthen research efforts on Pb-free PeLEDs in the field of environmentally friendly optoelectronics.