Application of a bodipy-C-70 dyad in triplet-triplet annihilation upconversion of perylene as a metal-free photosensitizer

作者：Wei, Yaxiong; Zheng, Min; Zhou, Qiaohui; Zhou, Xiaoguo^*; Liu, Shilin

来源：Organic and Biomolecular Chemistry, 2018, 16(31): 5598-5608.

DOI：10.1039/c8ob01410h

• PHOTOPHYSICAL PROPERTIES
• EXCITED-STATE
• ENERGY-TRANSFER
• LOW-POWER
• IN-VIVO
• LIGHT
• C-60
• C-70
• NANOPARTICLES
• COMPLEXES

A bodipy-C-70 dyad was synthesized and applied in triplet-triplet annihilation (TTA) upconversion of perylene as a novel metal-free organic photosensitizer. The photophysical processes were investigated by the methods of steady-state UV-Vis absorption and fluorescence spectroscopy, nanosecond time-resolved transient absorption spectroscopy, cyclic voltammetry, and density functional theory calculations. The bodipy-C-70 dyad showed an increased molar extinction coefficient up to 82 300 mol(-1) cm(-1) at 518 nm compared with the C-70 monomer. With photo-excitation of the bodipy moiety at 532 nm, the intramolecular singlet-singlet energy transfer between bodipy and C-70 units was efficient with a quantum yield of nearly 100%, and the lowest triplet state of the dyad was subsequently populated via ISC of the C-70 moiety, with a lifetime of ca. 80 mu s in toluene. Electrochemical investigation suggested that the intramolecular electron transfer of the excited dyad was thermodynamically prohibited in toluene due to the positive Delta G(CS) for charge-separation. With the presence of perylene in solution as the triplet energy acceptor and emitter, the TTA upconverted fluorescence was observed with a maximum quantum yield of 10.3%. The overall upconversion capability of 4417 M-1 cm(-1) exceeded that of C-70 approximately twofold. Moreover, the bodipy-C-70 dyad also exhibited an enhanced optical stability under intense irradiation. All data indicated that the dyad was another ideal photosensitizer for TTA upconversion of perylene in the fullerene derivative family.

• 出版日期2018-8-21
• 单位中国科学技术大学