Thermal Transport in Engineered Hybrid Organic-Inorganic Perovskite Metasurfaces

Halide perovskites have recently gained widespread attention for their exceptional optoelectronic properties, which have been illuminated by extensive spectroscopic investigations. In this study, nanophotonic surface engineering using a newly developed soft lithographic technique has been used to reproduce nanostructures with enhanced optical functionalities. The thermal sensitivity of the metasurfaces is first observed in the temperature-dependent photoluminescence (PL) spectra. In order to observe the local changes in heat transport induced by nanopatterning of the perovskite thin films, a noninvasive optical technique based on Raman spectroscopy is employed. The thermophysical properties of the engineered perovskite surfaces are extracted from the softening of the representative peak positions in the Raman spectra, which act as temperature markers. The investigation suggests a comparatively higher rise in the local temperature for the patterned thin films as compared to the pristine thin films. We characterize different imprint geometries on perovskite thin films in terms of both optical and thermal transport simultaneously and report for the first time the existence of a window of thermal tolerance for the metasurfaces within which optical efficiencies can still be maximized.