Oled fabrication with zno and organic active layer integration

Abstract

In this study, the 7B organic molecule was synthesized and employed as the active layer in organic light-emitting diodes (OLEDs). OLED devices were fabricated with Glass/ITO/PEDOT: PSS/7B/Al and Glass/ITO/PEDOT: PSS/7B/ZnO/Al architectures to investigate the role of ZnO as an electron transport layer (ETL) in device performance. Optical and electrical characterizations, including UV-Vis absorption, photoluminescence (PL), electroluminescence (EL), and current density-voltage (J-V) measurements, were conducted. Results indicate that ZnO integration slightly reduces the turn-on voltage (from 5.95 V to 5.10 V), facilitating electron injection. However, ZnO does not significantly enhance charge transport or overall efficiency, functioning primarily as an interfacial modification layer rather than an efficient ETL. Additionally, ZnO exhibits effective hole-blocking layer (HBL) properties, preventing hole leakage towards the cathode and contributing to charge carrier confinement within the emissive layer. The EL and chromaticity analyses confirm that the device emits in the blue-green region (similar to 492 nm), making it suitable for display and lighting applications. Further improvements in charge balance and efficiency require alternative ETL materials or optimized interface engineering.