Luminescence properties of K+doped double perovskite Cs2AgInCl6
K+doped double perovskite Cs2AgInCl6 nanomaterial was prepared by solid phase ball milling method,which is environmentally friendly without ligands.The crystal structure was studied by X-ray diffraction and Raman spectrum,and the luminescence properties were studied by excitation spectrum,emission spectrum,and time-resolved spectrum.The results show that the Cs2AgInCl6 is a cubic crystal,which belongs to Fm3m space group.Due to parity-forbidden transition,the photoluminescence quantum yield(PLQY)is low,less than 0.1％.When K+doping is less than 60％,it mainly replaces Ag+,which causes lattice expansion of Cs2AgInCl6,eliminates inversion symmetry of lattice structure,breaks parity forbidden transition,and enhances photoluminescence intensity of Cs2AgInCl6.The optimal doping ratio was 40％,the center wavelength of Cs2Ag0.6K0.4InCl6 was 640 nm,the half-height width was 180 nm,the average fluorescence lifetime was 29.2 ns and the PLQY reached 10.5％.When the doping ratio of K+exceeds 60％,K+begins to replace the position of Cs+,which results in the presence of cubic phase Cs2-xK1+x-yAgyInCl6 and monoclinic phase Cs2-xK1+xInCl6.These products are dominated by non-radiative recom-bination due to strong electron-phonon coupling.
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