Phys.org May 11, 2020
Perovskites ability to emit light over a broad wavelength range is widely attributed to broad luminescence with a large Stokes shift to self-trapped excitons forming due to strong carrier–phonon interactions. Researchers in the Netherlands highlight the extrinsic origin of their broad band emission. As shown by below-gap excitation, in-gap states in the crystal bulk are responsible for the broad emission. This insight advances the understanding of the emission properties of low-dimensional perovskites and question the generality of the attribution of broad band emission in metal halide perovskite and related compounds to self-trapped excitons…read more. Open Access TECHNICAL ARTICLE
Wide-field photoluminescence micrographs (230_175 μm) show how somePerovskite flakes appear bright green over their entire area (left panel), whilst other flakesexhibit a distinctly red-shifted emission (right panel). Credit: Loi lab, University of Groningen