Title: Energy transfer in hybrid halide compounds and its influence on the optical properties

Abstract: The synthesis of new hybrid halide materials has attracted significant research interest due to their potential optoelectronic applications. However, general design principles that explain and predict their properties are still limited. In this work, we aimed to elucidate the role of energy transfer processes in various series of hybrid halide materials. To study the influence of intermolecular interactions, we synthesized a series of hybrid halides with the composition ((C2H5)nNH4-n)2Sn1-xTexCl6 (n = 1 – 4). DFT calculations showed that the band dispersions of the bands involving Te-5s orbital character gradually decrease as the size of the organic cation increases, indicating a decreasing orbital overlap between neighboring [TeCl6]2– complexes. We characterized the photoluminescence (PL) of the Sn/Te solid solutions in these series to correlate the electronic and optical properties. The PL response shows no concentration quenching effects in the ((C2H5)4N)2Sn1-xTexCl6 series, which demonstrates electronically isolated [TeCl6]2– complexes. However, the series with smaller organic cations (n = 1–3) and higher electronic dimensionality exhibits concentration quenching effects, which decrease as a function of the Te-5s band dispersions in these compounds. The present results enable us to conclude that electronic dimensionality plays a crucial role in the photophysical properties of hybrid halide compounds and can be utilized to fine-tune their properties. Additionally, we demonstrated a simple approach to a semiquantitative electronic dimensionality analysis using Voronoi polyhedra. Although this approach relies only on structural data, it enables a rapid characterization of intermolecular interactions in hybrid materials. 

See more of Dr. Kelpov's research on his website: https://klepovlab.org/