Deng Fan, Lazorski Megan S, Castellano Felix N
Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
Philos Trans A Math Phys Eng Sci. 2015 Jun 28;373(2044). doi: 10.1098/rsta.2014.0322.
The near-visible-to-blue singlet fluorescence of anthracene sensitized by a ruthenium chromophore with a long-lived triplet-excited state, Ru(5-pyrenyl-1,10-phenanthroline)(3)(2), in acetonitrile was investigated. Low intensity non-coherent green light was used to selectively excite the sensitizer in the presence of micromolar concentrations of anthracene generating anti-Stokes, singlet fluorescence in the latter, even with incident power densities below 500 μW cm(-2). The resultant data are consistent with photon upconversion proceeding from sensitized triplet-triplet annihilation (TTA) of the anthracene acceptor molecules, confirmed through transient absorption spectroscopy as well as static and dynamic photoluminescence experiments. Additionally, quadratic-to-linear incident power regimes for the upconversion process were identified for this composition under monochromatic 488 nm excitation, consistent with a sensitized TTA mechanism ultimately producing the anti-Stokes emission characteristic of anthracene singlet fluorescence.
研究了在乙腈中，具有长寿命三重激发态的钌发色团Ru(5-芘基-1,10-菲咯啉)(3)(2)敏化的蒽的近可见光至蓝光单重态荧光。使用低强度非相干绿光在微摩尔浓度的蒽存在下选择性激发敏化剂，即使入射功率密度低于500 μW cm(-2)，也能在后者中产生反斯托克斯单重态荧光。所得数据与蒽受体分子的敏化三重态-三重态湮灭(TTA)导致的光子上转换过程一致，通过瞬态吸收光谱以及静态和动态光致发光实验得到证实。此外，在单色488 nm激发下，确定了该组合物上转换过程的二次到线性入射功率范围，这与最终产生蒽单重态荧光反斯托克斯发射特征的敏化TTA机制一致。
