Olivier Jean-Hubert, Bai Yusong, Uh Hyounsoo, Yoo Hyejin, Therien Michael J, Castellano Felix N
†Department of Chemistry, French Family Science Center, 124 Science Drive, Duke University, Durham, North Carolina 27708-0346, United States.
‡Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695-8204, United States.
J Phys Chem A. 2015 Jun 4;119(22):5642-9. doi: 10.1021/acs.jpca.5b03199. Epub 2015 May 22.
We report four supermolecular chromophores based on (porphinato)zinc(II) (PZn) and (polypyridyl)metal units bridged via ethyne connectivity (Pyr1RuPZn2, Pyr1RuPZnRuPyr1, Pyr1RuPZn2RuPyr1, and OsPZn2Os) that fulfill critical sensitizer requirements for NIR-to-vis triplet-triplet annihilation upconversion (TTA-UC) photochemistry. These NIR sensitizers feature: (i) broad, high oscillator strength NIR absorptivity (700 nm < λ(max(NIR)) < 770 nm; 6 × 10(4) M(-1) cm(-1) < extinction coefficient (λ(max(NIR))) < 1.6 × 10(5) M(-1) cm(-1); 820 cm(-1) < fwhm < 1700 cm(-1)); (ii) substantial intersystem crossing quantum yields; (iii) long, microsecond time scale T1 state lifetimes; and (iv) triplet states that are energetically poised for exergonic energy transfer to the molecular annihilator (rubrene). Using low-power noncoherent illumination at power densities (1-10 mW cm(-2)) similar to that of terrestrial solar photon illumination conditions, we demonstrate that Pyr1RuPZn2, Pyr1RuPZn2RuPyr1, and Pyr1RuPZnRuPyr1 sensitizers can be used in combination with the rubrene acceptor/annihilator to achieve TTA-UC: these studies represent the first examples whereby a low-power noncoherent NIR light source drives NIR-to-visible upconverted fluorescence centered in a spectral window within the bandgap of amorphous silicon.
我们报道了四种基于（卟啉基）锌（II）（PZn）和通过乙炔连接桥连的（多吡啶）金属单元的超分子发色团（Pyr1RuPZn2、Pyr1RuPZnRuPyr1、Pyr1RuPZn2RuPyr1和OsPZn2Os），它们满足了近红外到可见光三重态-三重态湮灭上转换（TTA-UC）光化学中敏化剂的关键要求。这些近红外敏化剂具有以下特点：（i）宽的、高振子强度的近红外吸收性（700 nm < λ(max(NIR)) < 770 nm；6 × 10(4) M(-1) cm(-1) < 消光系数(λ(max(NIR))) < 1.6 × 10(5) M(-1) cm(-1)；820 cm(-1) < 半高宽 < 1700 cm(-1)）；（ii）可观的系间窜越量子产率；（iii）长的、微秒时间尺度的T1态寿命；以及（iv）三重态在能量上有利于向分子湮灭剂（红荧烯）进行放能能量转移。使用与地面太阳光子照射条件下相似的功率密度（1 - 10 mW cm(-2)）的低功率非相干照明，我们证明Pyr1RuPZn2、Pyr1RuPZn2RuPyr1和Pyr1RuPZnRuPyr1敏化剂可以与红荧烯受体/湮灭剂结合使用以实现TTA-UC：这些研究代表了低功率非相干近红外光源驱动以非晶硅带隙内的光谱窗口为中心的近红外到可见光上转换荧光的首个实例。
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