Abstract
Low-dimensional hybrid metal halides are emerging as a highly promising class of single-component white-emitting materials for their unique broadband emission from self-trapped excitons (STEs). Despite substantial progress in the development of these metal halides, many challenges remain to be addressed to obtain a better fundamental understanding of the structure-property relationship and realize the full potentials of this class of materials. Here, via pressure regulation, a near 100% photoluminescence quantum yield (PLQY) of broadband emission is achieved in a corrugated 1D hybrid metal halide C(5) N(2) H(16) Pb(2) Br(6) , which possesses a highly distorted structure with an initial PLQY of 10%. Compression reduces the overlap between STE states and ground state, leading to a suppressed phonon-assisted non-radiative decay. The PL evolution is systematically demonstrated to be controlled by the pressure-regulated exciton-phonon coupling which can be quantified using Huang-Rhys factor S. Detailed studies of the S-PLQY relation for a series of 1D hybrid metal halides (C(5) N(2) H(16) Pb(2) Br(6) , C(4) N(2) H(14) PbBr(4) , C(6) N(2) H(16) PbBr(4) , and (C(6) N(2) H(16) )(3) Pb(2) Br(10) ) reveal a quantitative structure-property relationship that regulating S factor toward 28 leads to the maximum emission.