https://diode.zone/videos/watch/699eaea7-f4b0-4b6e-97d9-083147b1d626 Quantum Chemical Calculations of Electronic Structure and Absorption Spectra for Silicon-Clonidine and Silicon-Halogen Derivative of Clonidine Solar Cells The ability of heterocyclic amines to form hybrid solar cells at room temperature has recently been demonstrated [1,2]. But the further development of such hybrids requires theoretical research to find appropriate solutions to improve the PV efficiency. To understand the functional features of silicon-organic hybrids at the atomic level, it is necessary to clearly know the geometric, electronic structure and optical characteristics of clonidine and its halogen derivatives as well as their hybrids with silicon. Therefore, the change in electron density in the system due to the replacement of hydrogen atoms by halogens (F, Cl, Br, and I) in the organic part of the hybrids was studied by quantum chemistry. Calculations of electronic structure were performed by the density functional theory (DFT) method with the exchange-correlation functional B3LYP using the base set 3-21G (d, p) with valence cleavage in the FireFly code v.8.2 [3]. Electronic spectra were calculated by the TDDFT (nonstationary DFT) method with the same functional and basic set. Valence MOs in the range of 40x40 were included in the active configuration space. Analysis of the absorption spectra of hybrids with clonidine with a hybrid of fluorine, chlorine, bromine and substituted iodine revealed that in the range of 400-800 nm, the intensity of substituted chlorine is higher, which coincides with the experimental data. It is shown that the formation of a single-center silicon-clonidine hybrid leads to an increase in the UV absorption compared to the original clonidine, and the formation of a silicon-chloride derivative of clonidine hybrid leads to even greater shift of absorption bands to the UV region. The formation of a three- center hybrid leads to the expansion of the absorption in the direction of both long- and short- wavelengths. The inclusion of chlorine atoms in the clonidine increases the absorption capacity of the hybrid. The bond between the organic and the silicon is provided by both nitrogen and two carbon atoms, and a tetrahedral silicon atom on the surface. The bonds can be single-center Si – N and three-center Si – N as well as two-center Si – C; the total energy of the hybrid in the case of a single-center Si – N bond exceeds the energy of the three-center one. Research is in progress. presenter: Vadym Naumov V.Lashkaryov Institute of Semiconductor Physics, National academy of sciences of Ukraine, Kyiv, Ukraine Tue, 20 Oct 2026 10:08:14 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://diode.zone https://diode.zone/lazy-static/avatars/61b689b7-84d5-43c7-9fa8-e63a7fd1d952.png https://diode.zone/videos/watch/699eaea7-f4b0-4b6e-97d9-083147b1d626 All rights reserved, unless otherwise specified in the terms specified at https://diode.zone/about and potential licenses granted by each content's rightholder.