Mixed B-site driven [InBr4]− tetrahedral efficient blue emission

The [InX 4 ] − tetrahedron is a structure with stronger rigidity than the [InX 6 ] 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. In 3+ ions partially replace Pb 2+ 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 [PbBr 5 ] 3− pyramid and [InBr 4 ] − tetrahedra. In this way, we have achieved the efficient blue light emission of [InBr 4 ] − tetrahedron for the first time. Under 372 nm UV light excitation, (PPh 3 H) 4 [PbBr 5 ][InBr 4 ] can achieve efficient blue emission, the photoluminescence quantum yield is 74.03 %, and the emission center at 463 nm. The rigid environment and the [InBr 4 ] − tetrahedron are the sources of the minor Stokes shift, and the self-trapping exciton of the zero dimensions [InBr 4 ] − tetrahedron is the source of efficient blue light emission. Meanwhile, we found that there are two optical transition processes between [PbBr 5 ] 3− and [InBr 4 ] − . One is the transfer from the excited state of [PbBr 5 ] 3− to the excited state of [InBr 4 ] − , and triphenylphosphine acts as the energy transfer medium of the two. The other is the transfer from the ground state of [PbBr 5 ] 3− (donor) to the excited state of [InBr 4 ] − (acceptor).