Recently, The team of Professor Zou Bingsuo from SKL is entitled "Mixed B-site driven [InBr₄]^-tetrahedral efficient blueemission" was published in the Chemical Engineering Journal.

The [InX₄]⁻tetrahedron is a structure with stronger rigidity than the [InX₆]³⁻octahedron, which makes it a possible blue light emitting material. In this study, the method of mixed B-sites is used to control the polyhedral transition in the crystal structure. In³⁺ions partially replace Pb²⁺ions to form the mixed B sites of Pb-In. The electronegativity difference of both causes clear energy transfer between Pb and In. The movement of the electron cloud causes a change in the polyhedral structure, which promotes the formation of [PbBr₅]³⁻pyramid and [InBr₄]⁻tetrahedra. In this way, we have achieved the efficient blue light emission of [InBr₄]⁻tetrahedron for the first time. Under 372 nm UV light excitation, (PPh₃H)₄[PbBr₅][InBr₄] can achieve efficient blue emission, the photoluminescence quantum yield is 74.03 %, and the emission center at 463 nm. The rigid environment and the [InBr₄]⁻tetrahedron are the sources of the minor Stokes shift, and the self-trapping exciton of the zero dimensions [InBr₄]⁻tetrahedron is the source of efficient blue light emission. Meanwhile, we found that there are two optical transition processes between [PbBr₅]³⁻and [InBr₄]⁻. One is the transfer from the excited state of [PbBr₅]³⁻to the excited state of [InBr₄]⁻, and triphenylphosphine acts as the energy transfer medium of the two. The other is the transfer from the ground state of [PbBr₅]³⁻(donor) to the excited state of [InBr₄]⁻(acceptor).