Flexible silica films encapsulating hydrophilic CdTe quantum dots for application in white light emitting diodes

Abstract

Large flexible silica films encapsulating hydrophilic CdTe quantum dots (QDs) were fabricated via controlling the hydrolysis of 3-aminopropyltrimethoxysilane (APS). Hydrophilic CdTe quantum dots with green to red emitting were encapsulated in the films through a sol–gel incorporation process for retaining high photoluminescence (PL) efficiency and stability. Fluorescence microscopy and a scanning electron microscopy were employed to examine dispersion of CdTe QDs in the emitting films, which illustrated that structure of silica films was uniform. The PL stability of these flexible silica films was investigated in argon condition, the PL properties of the films encapsulated green-, yellow-, and red-emitting CdTe QDs were very stable. Furthermore, the silica-CdTe QDs emitting films revealed high PL stability under ultraviolet (UV) light irradiation, proper concentration of QDs in silica films can make the films more stable. In addition, different emission flexible silica-CdTe QDs films with large area were obtained. The dual-emitting silica-CdTe QDs films exhibited coordinates (0.384, 0.350) in the Commission Internationale de I׳Eclairage (CIE) chromaticity diagram under blue light as excitation source. Due to flexibility, adjustable colors, high stability, large area, easy to operate, silica-CdTe QDs emitting films show potential application in lighting devices and flat panel displays.