Rare‐Earth‐Based Perovskite Cs ₂ AgScCl ₆ :Bi for Strong Full Visible Spectrum Emission

Most luminescent materials can only emit light with a particular wavelength. In general, various phosphors with complementary spectral ranges are mixed to realize full‐spectrum lighting. Therefore, the integration of luminescence at different wavebands in the single component matrix to obtain white emission is the optimal strategy for designing lighting materials. Thus, Sc‐based double perovskite Cs 2 AgScCl 6 : x Bi with adjustable free exciton and self‐trapped exciton luminescence is synthesized by the vacuum evaporation assisted synthetic method. This perovskite can be used as white phosphor to assemble a high‐quality white lighting device. Density functional theory calculations have revealed that the introduction of Bi optimizes the electron transfer and suppresses the defects in Cs 2 AgScCl 6 , which leads to excellent luminescent performance in a broad wavelength range. This work provides a new concept and strategy for the design and preparation of rare‐earth optical perovskites in the future.