Eco-Friendly InxGa1-xN Colloidal Quantum Dots for Light Emitting Diodes

Abstract We report the synthesis of emissive In x Ga 1-x N colloidal quantum dots (CQDs) by using a hot-injection method and the demonstration of quantum dot light-emitting diodes (QLEDs) utilizing these CQDs. We successfully synthesized size- and composition-tunable In x Ga 1-x N CQDs (x= 0 ~ 1) using the hot injection method and investigate the structural and optical properties of these CQDs as a function of the ratio of In to Ga. Through particle size control, green and blue emissive In x Ga 1-x N CQDs were realized. The X-ray absorption fine structure (XAFS) results indicate that the crystal states of the In x Ga 1-x N CQDs consist of multiphase states; multipeak photoluminescence (PL) resulted from these multiphase states. The multiple peaks correspond to the changes in the PL spectra due to variations in the metal fractions. Inverted structured QLEDs exhibited green electroluminescence (EL) emission and a maximum luminance of ~45 cd/m 2 . These results indicate that In x Ga 1-x N CQDs can serve as promising alternatives to conventional cadmium-containing CQDs in various optoelectronic applications, e.g., eco-friendly displays.