Cesium lead halide perovskite nanocrystals for ultraviolet and blue light blocking

Abstract Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br) 3 , as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br) 3 nanocrystals are well dispersed in the ethyl cellulose (EC) matrix to compose a UV and blue light shielding film, and the absorption edge of the film is tunable by adjusting Cl to Br ratio using anion exchange. The CsPbCl 2 Br-EC film exhibits a transmittance of 5% at 459 nm, 90% at 478 nm and 95% in the range of 500–800 nm, which makes it excellent for UV and blue light shielding. In addition, the as-prepared EC-CsPb(Cl/Br) 3 film shows excellent photostability under UV irradiation. Results demonstrate that this EC-CsPb(Cl/Br) 3 based materials with sharp absorbance edges, tunable blocking wavelength, and high photostability can be useful for the applications in UV and blue light blocking and optical filters