Blue-Emitting InP/GaP/ZnS Quantum Dots with Enhanced Stability by Siloxane Capping: Implication for Electroluminescent Devices

InP quantum dots (QDs) with low toxicity are an ideal alternative to Cd-based QDs. However, the optical properties and stability of blue-emitting InP QDs are far inferior to those of red and green QDs. In this work, we report the synthesis of highly fluorescent InP/GaP/ZnS core/shell/shell QDs with an emission wavelength of 484 nm and photoluminescence quantum yield of 71%, along with a full width at half-maximum as narrow as 45 nm. In addition, we encapsulated the QDs with siloxane via specific ligand exchange and condensation reactions to improve their stability. The corresponding siloxane capping QD light-emitting device (QLED) shows a maximum luminance of 690 Cd m–2, an external quantum efficiency of 0.09%, and a much longer lifetime than pristine QDs. As a result, these enable the siloxane capping QDs to achieve a much stronger storage stability and a longer QLED lifetime than pristine QDs.