Hisamitsu Shota, Miyano Junji, Okumura Keisuke, Hui Joseph Ka-Ho, Yanai Nobuhiro, Kimizuka Nobuo
Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
JST-PRESTO, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan.
ChemistryOpen. 2019 Nov 26;9(1):14-17. doi: 10.1002/open.201900304. eCollection 2020 Jan.
Visible-to-ultraviolet (vis-to-UV) triplet-triplet annihilation based photon upconversion (TTA-UC) is achieved in a non-volatile chromophoric ionic liquid (IL) for the first time. A novel IL is synthesized by combining UV-emitting anion 4-(2-phenyloxazol-5-yl)benzenesulfonate (PPOS) and trihexyltetradecylphosphonium cation (P). The nanostructured organization of chromophoric anions is demonstrated by synchrotron X-ray and optical measurements. When the IL is doped with a triplet sensitizer tris(2-phenylpyridinato)iridium(III) (Ir(ppy)), the visible-to-UV TTA-UC with a relatively low threshold excitation intensity of 61 mW cm is achieved. This is due to a large triplet diffusion coefficient in the IL (1.4×10 cm s) as well as a high absorption coefficient 15 cm and a long PPOS triplet lifetime of 1.55 ms, all implemented in the condensed IL system. This work demonstrates the unique potential of ILs to control chromophore arrangements for desired functions.
首次在非挥发性发色离子液体（IL）中实现了基于可见-紫外（vis-UV）三重态-三重态湮灭的光子上转换（TTA-UC）。通过将发射紫外光的阴离子4-(2-苯基恶唑-5-基)苯磺酸盐（PPOS）与三己基十四烷基鏻阳离子（P）结合，合成了一种新型离子液体。通过同步加速器X射线和光学测量证明了发色阴离子的纳米结构组织。当该离子液体掺杂三重态敏化剂三(2-苯基吡啶)铱(III)（Ir(ppy)）时，实现了可见-紫外TTA-UC，其阈值激发强度相对较低，为61 mW cm 。这是由于离子液体中具有较大的三重态扩散系数（1.4×10 cm s ）、较高的吸收系数15 cm以及PPOS三重态的长寿命1.55 ms，所有这些都在凝聚态离子液体体系中得以实现。这项工作证明了离子液体在控制发色团排列以实现所需功能方面的独特潜力。
