Gao Min, Zeng Le, Jiang Linhan, Zhang Mingyu, Chen Yong, Huang Ling
Jiangxi Key Laboratory for Microscale Interdisciplinary Study, Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
Research Center for Analytical Sciences and Tianjin Key Laboratory of Biosensing and Molecular Recognition, Haihe Laboratory of Sustainable Chemical Transformations, College of Chemistry, Nankai University, Tianjin 300192, China.
Molecules. 2023 Jul 18;28(14):5474. doi: 10.3390/molecules28145474.
Triplet-triplet annihilation upconversion (TTA-UC) has considerable potential for emerging applications in bioimaging, optogenetics, photoredox catalysis, solar energy harvesting, etc. Fluoroboron dipyrrole (Bodipy) dyes are an essential type of annihilator in TTA-UC. However, conventional Bodipy dyes generally have large molar extinction coefficients and small Stokes shifts (<20 nm), subjecting them to severe internal filtration effects at high concentrations, and resulting in low upconversion quantum efficiency of TTA-UC systems using Bodipy dyes as annihilators. In this study, a Bodipy dimer (B-2) with large Stokes shifts was synthesized using the strategy of dimerization of an already reported Bodipy annihilator (B-1). Photophysical characterization and theoretical chemical analysis showed that both B-1 and B-2 can couple with the red light-activated photosensitizer PdTPBP to fulfill TTA-UC; however, the higher fluorescence quantum yield of B-2 resulted in a higher upconversion efficiency () for PdTPBP/B-2 (10.7%) than for PdTPBP/B-1 (4.0%). This study proposes a new strategy to expand Bodipy Stokes shifts and improve TTA-UC performance, which can facilitate the application of TTA-UC in photonics and biophotonics.
三重态-三重态湮灭上转换（TTA-UC）在生物成像、光遗传学、光氧化还原催化、太阳能收集等新兴应用中具有巨大潜力。氟硼二吡咯（Bodipy）染料是TTA-UC中一种重要的湮灭剂类型。然而，传统的Bodipy染料通常具有较大的摩尔消光系数和较小的斯托克斯位移（<20 nm），这使得它们在高浓度下会受到严重的内滤效应影响，导致以Bodipy染料作为湮灭剂的TTA-UC系统的上转换量子效率较低。在本研究中，采用已报道的Bodipy湮灭剂（B-1）的二聚化策略合成了具有大斯托克斯位移的Bodipy二聚体（B-2）。光物理表征和理论化学分析表明，B-1和B-2均可与红光激活的光敏剂PdTPBP耦合以实现TTA-UC；然而，B-2较高的荧光量子产率使得PdTPBP/B-2的上转换效率（）（10.7%）高于PdTPBP/B-1（4.0%）。本研究提出了一种扩大Bodipy斯托克斯位移并提高TTA-UC性能的新策略，这有助于TTA-UC在光子学和生物光子学中的应用。
