Теоретичне дослідження фотоелектричних властивостей гексабромотелурату 3-метилтіо-4-феніл-5-феніламіно-1,2,4-тризол-1-ію

Abstract

This work is devoted to the theoretical study of photoelectric and semiconductor properties of 3- methylthio-4-phenyl-5-phenylamino-1,2,4-triazole hexabromotellurate, a compounds chemically and structurally related to the halide perovskite derivatives. The energy and environmental problems of the past decades have stipulated the active search and development of new functional materials with high efficiency of solar energy conversion, which do not contain highly toxic elements and thus do not endanger environment. In this regard, one of the most promising areas of systematic research is the synthesis and study of new hybrid organic-inorganic compounds belonging to the family of perovskite and its structural derivatives. As it has been earlier reported in the literature that some halide perovskite derivatives exhibit photoelectric and semiconducting properties, and given the previous experience in the laboratory synthesis of 3-methylthio-4-phenyl-5-phenylamino-1,2,4-triazole hexabromotellurate, a series of theoretical quantum chemical calculations have been carried out to determine the principal photoelectric properties of this compound and to evaluate the possible influence of the organic cation of the compound on its photoabsorption and semiconducting properties. The positions of the hydrogen atoms were previously optimized by the semi-empirical PM7 method; the calculations of the total energy, molecular orbitals, energy states, and absorption spectra were performed within the framework of the DFT theory by using the РВЕ functional. The DZVPMOLOPT- SR-GTH double-zeta basis was used for all elements as the basis set except Br and Te for which the TZVP-MOLOPT-SR-GTH triple-zeta basis was used. The GTH-PBE pseudopotential was used for all atoms. For the study of photoabsorption properties, the first 80 excited states were calculated. The obtained results have shown a fundamental possibility to correct the photoabsorption properties of hybrid [TeBr6]-containing materials by changing the structure of the organic cation in the hexabromotellurate salt. The bandgap is calculated to be 2.78 eV, which is typical for similar organic hexabromotellurates with semiconducting properties, and this fact confirms the scientific validity of the calculation methods chosen and applied in the present work. The results of the study can serve as a reliable scientific basis for the development of molecular design algorithms for chemically related hybrid organic-inorganic perovskites and their derivatives. Keywords: hybrid perovskites; DFT; semiconductors; photoelectric materials.