取代效应对脂滴检测NAPBr染料分子的双光子吸收和激发态性质影响的理论探究

双光子荧光染料分子在生物医学成像中具有广阔的应用前景，但取代效应对分子结构以及光物理性质影响的探求相对匮乏. 本文设计并研究了一系列脂滴检测染料分子，分析了分子的光学性质以及无辐射跃迁等. 通过分子内弱相互作用和电子- 空穴布居分析，阐述了其内在机理. 结果表明，所研究的分子均具有优良的光物理性能、高效荧光量子产量、大的斯托克斯位移以及显著的双光子吸收截面等. 本工作合理地解释了实验现象并阐述了取代效应对脂滴检测NAPBr染料分子的双光子吸收和激发态性质的影响，这为设计新型的高效有机分子提供了理论指导.

Effect of Substitution Site on Two-Photon Absorption and Excited States Properties of Lipid Droplets Detection NAPBr Dyes: a Theoretical Perspective

Two-photon fluorescence dyes have shown promising applications in biomedical imaging. However, the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated in detail. In this work, a series of new lipid droplets detection dyes are designed and studied, molecular optical properties and non-radiative transitions are analyzed. The intramolecular weak interaction and electron-hole analysis reveal its inner mechanisms. All dyes are proven to possess excellent photophysical properties with high fluorescence quantum efficiency and large stokes shift as well as remarkable two-photon absorption cross section. Our work reasonably elucidates the experimental measurements and the effects of substitution site on two-photon absorption and excited states properties of lipid droplets detection NAPBr dyes are highlighted, which could provide a theoretical perspective for designing efficient organic dyes for lipid droplets detection in biology and medicine fields.