We report room temperature broadband sub-gap emission from undistorted hybrid organic inorganic perovskite-like layered materials. We characterize this photoluminescence using temperature dependent x-ray diffraction, photoluminescence and low frequency vibrational Raman techniques. The broadband emission with full width at half maximum of about 300nm spans wavelengths from 625 to 1000nm. We hypothesize molecular disorder causes this broadband emission. This hypothesis is based on changes in material properties across a thermochromic phase transition. Analysis of shapes and widths of Raman peaks after cycling through the phase transition revealed significant changes to these spectral features. Given the large contribution of molecular reorientation to the structural changes involved in the phase transition, we conclude these changes to Raman features result from a simultaneous disorder-order transition. We compare this proposed mechanism to those previously reported to explain broadband light emission from similar materials. Our results provide a novel approach to understanding mechanisms involved in the broadband emission from hybrid materials which is key to their proposed application in the development of better light emitting diodes.

Broadband light emission in hybrid perovskites: Assessing the role of molecular disorder

2019 Spring National Meeting

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