Optimized CdO loading for high-efficiency luminescence in Alq₃ hybrids

Hybrid organic-inorganic systems offer new opportunities for tailoring optoelectronic properties in emissive materials. In this work, Alq₃/CdO composites were synthesized with varying CdO loadings (5–50 wt%) to elucidate how inorganic incorporation governs crystallization, morphology, and luminescence. XRD and SEM analyses reveal that 10 wt% CdO induces a well-defined triclinic Alq₃ phase with flower-like microcrystals and uniformly distributed CdO microwhiskers, indicating optimal hybrid interface formation. UV–Vis and PL spectroscopy show that low to moderate CdO concentrations (5–10 wt%) enhance photoluminescence, driven by electron transfer from CdO to the quinoline ligands, which increases ligand electron density and promotes radiative recombination. Higher CdO loadings (≥50 wt%) lead to dense inorganic agglomerates, dominant CdO reflections in XRD, and pronounced PL quenching due to non-radiative recombination pathways. Collectively, the results demonstrate an organic-to-inorganic transition with increasing CdO content and identify 10 wt% as the optimum composition for maximizing luminescence yield. The improved crystallinity, enhanced charge transfer, and strengthened emissive behaviour at intermediate CdO loadings highlight the potential of Alq₃/CdO hybrids as advanced electron-transport and emissive materials for OLED technologies. • CdO incorporation systematically tunes the structural and optical properties of Alq₃ producing organic–inorganic hybrids. • XRD and SEM confirm optimal hybridization at 10 wt% CdO, showing triclinic Alq₃. • Photoluminescence intensity increases at 5–10 wt% CdO due to electron transfer from CdO to quinoline ligands. • High CdO loading (≥50 wt%) induces inorganic agglomeration, leading to suppression of PL emission. • Moderate CdO content improves electron mobility and interfacial charge transfer in OLEDs.