Blue light irradiation-stirred washing high luminescence and highly stable CsPbBrI2 quantum dots modified with CaO for backlight display

Abstract

Perovskite quantum dots (QDs) have become the star material for liquid crystal display (LCD). However, instability affects its practical application. Herein, CsPbBrI₂ quantum dots (CsPbBrI₂ QDs) with high quantum efficiency have been successfully precipitated in situ by adding CaO to the Li-Al-Si glass substrate. The photoluminescence quantum yield (PLQY) was adjusted from 64.5 % to 87.5 %. At the same time, we adopted a new strategy of blue light irradiation-stirred water washing. When blue light irradiation and stirred water washing interact synergistically, the CsPbBrI₂ QDs detached from the glass surface, while smaller CsPbBrI₂ QDs continued to grow. This process successfully resulted in CsPbBrI₂ QDs with high luminescence intensity and high stability. Moreover, when exposed to 60°C, 90 % relative humidity (RH), and 2000 nit blue light for 120 h (h), the treated sample could retain 95 % of the original emission intensity. The color gamut of the prepared CsPbBrI₂@glass@PS light conversion film covered 122 % of the NTSC 1953 standard and 90 % of the Rec. 2020 standard. It provided great value for the commercialization of QDs in backlight display applications.