Ball milling synthesis and optical properties of Na and Bi ions Co-doped double perovskite Cs2AgInCl6

Abstract

Double perovskite Cs2AgInCl6 is a new direct band gap semiconductor material. Compared with traditional perovskite CsPbX3 (X = Cl, Br, I), double perovskite Cs2AgInCl6 has good stability and wide fluorescence half peak width. This study reports the mechanochemical synthesis, characterization and application of a lead-free double perovskite Cs2AgInCl6 doped with Na and Bi ions. It was found that through a facile room temperature mechanical ball milling process, the double perovskite structure can be obtained within 30 min. Then, Na and Bi ions were used to dope to optimize its luminescence properties. By this synthesis method, the sample with the best doping ratio obtained in the experiment is Cs2Ag0.7Na0.3In0.9Bi0.1Cl6 with the photoluminescence quantum yield (PLQY) of 32.7%. The X-ray diffraction (XRD) and photoluminescence (PL) results show that Na and Bi ions can promote the crystallization and optimize the luminescence properties of Cs2AgInCl6. The theoretical calculation results show that both conduction band minimum (CBM) and valance band maximum (VBM) of Cs2Ag0.7Na0.3In0.9Bi0.1Cl6 are flat, which is favorable for the generation of self-trapped excitons. Packaging Cs2Ag0.7Na0.3In0.9Bi0.1Cl6 sample on an ultraviolet (UV) LED chip, and a warm white LED with good performance can be obtained, which shows a bright potential application in the field of white LED.