In Situ Fabrication Of Perovskite Quantum Dots Based Optical Films For Backlight Application

Perovskite quantum dots have the characteristics of high color purity,tunable spectra,high photoluminescence quantum yield and simple low-cost processing technology,they have become the star materials in the field of display applications.The quantum dot based optical film for backlight technology in liquid crystal display is the mainstream of quantum dot materials in display applications.The stability of quantum dots can be greatly improved by embedding them into multi-layer polymer barriers to form quantum dots optical films,however,the fabrication process of quantum dot optical films is very complicated including the quantum dots synthesis,purification,post-processing and film-forming process,and the resulting high cost limits the large-scale production and application of quantum dot optical films.In this paper,high performance perovskite quantum dot optical films were successfully fabricated by using a simple and novel in situ fabrication technique,and their application in backlights were also demonstrated.The main contents are as follows:(1)In situ fabrication of perovskite quantum dot based optical filmsIn this paper,the common sovent processing of perovskite quantum dot and poly(vinylidene fluoride)(PVDF)in N,N-dimethylformamide was the basis of in situ fabrication technology.The crystallization of perovskite quantum dots and PVDF matrix was separated by controlling the solvent evaporation process.Perovskite quantum dot based optical films with excellent photoluminescence properties and performance were fabricated,including high photoluminescence quantum yield(~94.5%),narrow spectra(~24 nm),turnable emission wavelength(440 nm~730 nm),and high transparency(> 80%),as well as flexibility(~4.5 times stretching),piezoelectricity(~2.5 V),water resistance and UV resistance.(2)Perovskite quantum dot based optical film for backlight applicationIn this paper,perovskite quantum dot based optical film was integrated into the LED by using on-chip backlight geometry,the color coordinate of resulting LED backlight is(0.272,0.278),the color gamut is 121% NTSC and the luminous efficiency is 109 lm/W,which have could meet the requirements of backlight application.And the perovskite quantum dot based optical film was further applied to the on-surface backlight geometry,the color gamut of finally obtained liquid crystal display prototype is 105% NTSC.And so,the great potential of perovskite quantum dot based optical film in backlight applications was verified.