Enhancing scattering strength improvement and color uniformity in white light-emitting diodes using high concentration of cobalt(II) oxide

Abstract

The study herein investigates the structural development of cobalt(II) oxide (CoO) thin films grown on Ag (0 0 1) substrates and evaluates their impact on optical performance in white light-emitting diodes (WLEDs). The structural and chemical properties of CoO films were characterized using grazing-incidence X-ray diffraction (GIXD), Xray photoelectronic spectroscopic (XPS), as well as low-power electronic diffracting (LEED). The outcomes reveal that CoO films initially grow pseudomorphically up to 3-4 monolayers, followed by gradual relaxation toward the bulk lattice parameter. A periodic mismatch dislocation network forms at approximately 8 monolayers, leading to lattice tilting and the formation of ordered nanoscale domains. In addition, the incorporation of CoO as a scattering material in WLEDs significantly improves light scattering and color uniformity, while maintaining stable luminous performance. Compared with conventional scattering materials, CoO demonstrates lower scattering loss and reduced chromatic deviation, making it a promising candidate for high-precision optoelectronic applications.