Low-dimensional perovskites have—in view of their high radiative recombination rates—shown great promise in achieving high luminescence brightness and colour saturation. Here we investigate the effect of electron–phonon interactions on the luminescence of single crystals of two-dimensional perovskites, showing that reducing these interactions can lead to bright blue emission in two-dimensional perovskites. Resonance Raman spectra and deformation potential analysis show that strong electron–phonon interactions result in fast non-radiative decay, and that this lowers the photoluminescence quantum yield (PLQY). Neutron scattering, solid-state NMR measurements of spin–lattice relaxation, density functional theory simulations and experimental atomic displacement measurements reveal that molecular motion is slowest, and rigidity greatest, in the brightest emitter. By varying the molecular configuration of the ligands, we show that a PLQY up to 79% and linewidth of 20 nm can be reached by controlling crystal rigidity and electron–phonon interactions. Designing crystal structures with electron–phonon interactions in mind offers a previously underexplored avenue to improve optoelectronic materials' performance.

考虑到低维钙钛矿的高辐射复合率，它们有望实现高发光亮度和色彩饱和度。在这里，我们研究了电子-声子相互作用对二维钙钛矿单晶发光的影响，表明减少这些相互作用可以导致二维钙钛矿中的亮蓝色发射。共振拉曼光谱和形变势分析表明，强的电子-声子相互作用导致快速的非辐射衰变，并降低了光致发光的量子产率（PLQY）。中子散射，自旋晶格弛豫的固态NMR测量，密度泛函理论模拟和实验性原子位移测量表明，分子运动最慢，刚度最大，在最亮的发射器中。通过改变配体的分子构型，我们显示通过控制晶体刚度和电子-声子相互作用，可以达到高达79％的PLQY和20 nm的线宽。考虑电子-声子相互作用的晶体结构设计为提高光电子材料的性能提供了以前未被探索的途径。