Optical Properties Enhancement of Electrosprayed Quantum Dot/Polymer Nanohybrid Films by a Solvent Vapor Treatment

Abstract

Colloidal quantum dot (QD)/polymer nanohybrid (NHB) films were fabricated by electrospray method, and the optical properties of the NHB films are improved by a post-treatment, named solvent vapor treatment (SVT). Dodecanethiol (DDT)-capped AgIn5S8/ZnS QDs and poly(methyl methacrylate) (PMMA) were used as the QD and the polymer matrix respectively. The morphological and optical properties of high QD loaded (similar to 75 part) NHB films are significantly altered by SVT. The porous morphology of as e-sprayed films are completely disappear after SVT yielding continuous films. The effects of SVT are varied depending on the types of solvents and chloroform worked most efficiently among studied solvents because of the similar solubility parameter with PMMA. The optical transmission of the NHB films was dramatically improved by SVT using chloroform. The e-sprayed NHB films after SVT were applied as the down conversion phosphor for white light emitting diodes (LED). Using an InGaN blue LED with the NHB films, the luminous efficacy of 39.7 Im/W at 3,087 K was achieved with a forward current of 60 mA.