Exploring Cs2AgBiBr6 halide double perovskite as a lead-free emissive material for perovskite LEDs Kamal Kumar Jain, Sarita Yadav, Saral K Gupta, C M S Negi Physica Scripta, 2025 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.
Investigating charge injection, transport, and electronic performance in rGO-integrated TIPS pentacene blend devices Saumya Paliwal, Amrita Singh, Aditi Upadhyaya, Saral Kumar Gupta, C M S Negi Physica Scripta, 2025 This study demonstrates the successful integration of reduced graphene oxide (rGO) into the TIPS pentacene framework, leading to significant enhancements in device performance. The fabricated devices exhibit ideality factors ranging from 2.1 to 2.6, indicating that trap-assisted Shockley Read Hall (SRH) recombination dominates the charge recombination mechanism. The Schottky barrier height (SBH) values, estimated using both the Richardson-Schottky (RS) thermionic emission model and an alternative calculation method, show excellent consistency, confirming the reliability of both approaches. Leakage current is primarily dictated by a direct tunnelling mechanism, while charge conduction is well-explained by the space-charge-limited current (SCLC) model. Optimal device performance, characterized by peak hole mobility and shortest rise times, is achieved with 3% rGO concentration, highlighting its potential for high-speed switching applications. Capacitance-frequency (C–f) analysis reveals a slight frequency dependence at lower frequencies, attributed to charge traps, while the dielectric constants obtained from C–f measurements align with those derived from the RS thermionic emission model. These findings demonstrate the suitability of rGO-doped TIPS pentacene for advanced electronic devices, particularly in high-speed applications.
