Study On Synthesis And Photoelectric Properties Of Pyridine-tetrathiafulvalene Derivative-based Semiconductors

Multi-spectrum optoelectronic semiconductors are a class of materials that can convert optical signals in multiple frequency bands into electrical signals,and have important applications in photodetection,solar energy conversion,and catalysis.At present,optoelectronic devices that can meet the application in the full solar spectral region（about 295–2500 nm）are mainly supported by semiconductors such as Si（about300-1100 nm）and In Ga As（about 900-3000 nm）,and there is still a lack of mature commercial products spanning the full spectrum,causing the corresponding system to have problems such as complex structure,high manufacturing cost,and difficult maintenance.Some emerging semiconductors have a wide photoelectric response range,but there are still many deficiencies.For example,the current popular perovskite material has an absorption range of 1300 nm,but it still cannot cover the full solar spectrum,and its stability needs to be improved.Graphene semiconductors can cover the full solar spectrum,but have a low absorption coefficient（less than 3%for a single layer）and a large dark current.Therefore,it is still of great significance to develop material design strategies that can broaden the photoelectric response band and explore multi-spectral optoelectronic semiconductors with excellent comprehensive properties.Tetrathiafulvalene and its derivatives are a class of compounds to construct classical charge transfer complex semiconductors.This dissertation takes pyridine-tetrathiafulvalene derivative-based semiconductor compounds as the research object,and focuses on the development of material design strategies that can broaden the photoelectric response band.The following two main findings are made:1)For the first time,it was found that the Py-TTF-Py(C₁₆H₁₀N₂S₄)compound can further undergo charge separation under light induction,produce coloration,increase the concentration of free radicals,and significantly enhance the absorption intensity of the full solar spectrum,but the problem of weak absorption in the infrared region remains to be solved.2)Aiming at the problem of weak absorption in the infrared region,two lead halide semiconductors（Dt V）₂Pb₃I₁₀and（Dt Q）₂Pb₃I₁₀were synthesized by transforming tetrathiafulvalene derivatives into viologen ionic structures,and thermally induced charge separation and coloration were found.After coloring,the absorption in the infrared region is significantly enhanced.Representatively,compound（Dt V）₂Pb₃I₁₀increases the conductivity by about 86 times after thermally induced coloration,and the absorption spectrum broadens by 1800 nm and reaches 2500 nm,which achieves full coverage and high absorption of the solar spectrum.These new semiconductors have a larger photoelectric response range than lead halide perovskites.