Zhang Xiangxi, Jin Feng, Li Xintong, Wang Jun, Zhou Qing
State Key Laboratory of Bio-based Fiber Materials, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
Engineering Research Center for Eco-Dyeing & Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
J Phys Chem B. 2025 Jul 31;129(30):7852-7860. doi: 10.1021/acs.jpcb.5c03897. Epub 2025 Jul 18.
In this study, the luminescence properties and emission mechanisms of five halogenated silanes, hexamethyldisiloxane (HT), chloromethylsilane (CT), iodomethylsilane (IT), chlorosilane (CS), and 1,1,2,2-perfluorooctyltrimethoxysilane (FS) are systematically investigated. The effects of halogen type, substitution position, and temperature on luminescence efficiency, Stokes shift, and phosphorescence lifetime are elucidated through fluorescence, phosphorescence analysis, and theoretical calculations (at room temperature and 77 K). The results revealed that CS exhibits excellent fluorescence emission at 365 nm and significantly prolonged low-temperature phosphorescence lifetime due to its reduced nonradiative transitions and minimized excited-state energy dissipation. IT exhibited enhanced phosphorescence under liquid nitrogen, which can be attributed to the heavy-atom effect of the iodine atom and strong spin-orbit coupling. The Stokes shift analysis of excitation-emission spectra demonstrated that the energy gap between the excited and ground states can be reduced by the substituted halogen atoms. Moreover, CS displays the smallest shift among the five halogenated silanes, and its maximum emission wavelength is red-shifted with induced temperature, reflecting increased energy dissipation. The electron-hole distribution analysis confirms that halogens regulate luminescence efficiency by modulating electron transfer pathways (from high-electronegativity atoms to low-electronegativity regions) and spin-coupling strength. This work not only enriches the understanding of nonconventional luminescence in pure liquids but also provides theoretical foundations for the design of high-performance silicon-based optoelectronic materials.
在本研究中，系统地研究了五种卤代硅烷，即六甲基二硅氧烷（HT）、氯甲基硅烷（CT）、碘甲基硅烷（IT）、氯硅烷（CS）和1,1,2,2-全氟辛基三甲氧基硅烷（FS）的发光特性和发射机制。通过荧光、磷光分析以及理论计算（在室温及77 K下）阐明了卤素类型、取代位置和温度对发光效率、斯托克斯位移和磷光寿命的影响。结果表明，CS在365 nm处表现出优异的荧光发射，并且由于其非辐射跃迁减少和激发态能量耗散最小化，低温磷光寿命显著延长。IT在液氮下表现出增强的磷光，这可归因于碘原子的重原子效应和强自旋轨道耦合。激发-发射光谱的斯托克斯位移分析表明，取代的卤素原子可减小激发态与基态之间的能隙。此外，CS在五种卤代硅烷中表现出最小的位移，并且其最大发射波长随温度升高发生红移，这反映了能量耗散增加。电子-空穴分布分析证实，卤素通过调节电子转移途径（从高电负性原子到低电负性区域）和自旋耦合强度来调节发光效率。这项工作不仅丰富了对纯液体中非传统发光的理解，而且为高性能硅基光电子材料的设计提供了理论基础。
