Preparing the photo- and heat-stable PGMA/CdTe quantum dot composite films and exploring devices for LED-display poster design

Inorganic quantum dots (QDs) are used in color displays because of wide photo-absorption and controllable photoluminescence (PL) colors, but their PL stability may be low due to surface defects. To overcome it, we prepared CdTe QDs with different sizes (~ 3.8, 4.4 and 5.0 nm) and poly(glycidyl methacrylate) (PGMA)/CdTe composite films. An increased size of QDs made them emit the green, yellow and red light successively. With an increased PL emission wavelength, the films emitted bright light with various colors. Compared to QDs solutions, the composite films have the almost unchanged fluorescence emission wavelengths (536–612 nm) and high PL intensity. The latter has an improved PL stability under optical and thermal conditions. The green-emitting film maintains ~ 81% of PL intensity after 24 h of photo-irradiation as well as ~ 91% of PL intensity at 120 °C. The green and white light-emitting diode (LED) devices were prepared using composite films, and the fluorescent emissions with bright colors were acquired. This study provides a valuable guideline for preparing the polymer/inorganic quantum dot composite films used in the LED poster display screens with bright stable fluorescence emissions.