Fabrication of transparent ultrathin films with ordered solid luminescence by LBL assembly of CdTe quantum dots with exfoliated vermiculite

Abstract

Quantum dots luminescent films have great potential for application in lasers, optoelectronics, solid-state light-emitting diodes, and optical devices. This work describes multilayer ordered vermiculite-based luminescent thin films (VLFs) with 2D architecture via layer-by-layer assembly of PDDA-modified CdTe QDs on exfoliated vermiculite (VMT). The assembly of negative CdTe QDs and negative VMT was achieved, overcoming the nonluminance of solid CdTe QDs. The ordered VLFs possess periodic layered structures involving heterogeneous superlattices associated with individual VMT layers. The rational combination of luminescent components affords precise control of the emission wavelength and intensity, resulting in a gradual change in luminescence intensity in the selected light-emitting spectral region upon increasing the number of deposition cycles. Compared to the CdTe QDs, the fluorescence lifetime of VLFs is improved owing to the ordered structure. This work provides a facile approach to fabricate heterogeneous VLFs with high luminous properties and optical stability, which is expected to prevent easy aggregation of luminescent materials and can be potentially applied in light displays and multicolor optical and optoelectronic devices.