Excited-State THz Vibrations in Aggregates of PtII Complexes Contribute to the Enhancement of Near-Infrared Emission Efficiencies

作者：Wei, Yu-Chen; Chen, Bo-Han; Ye, Ren-Siang; Huang, Hsing-Wei; Su, Jia-Xuan; Lin, Chao-Yang; Hodgkiss, Justin; Hsu, Lian-Yan; Chi, Yun^*; Chen, Kai^*; Lu, Chih-Hsuan^*; Yang, Shang-Da^*; Chou, Pi-Tai^*

来源：Angewandte Chemie - International Edition, 2023, 62(16).

DOI：10.1002/anie.202300815

• Aggregation
• Energy Gaps
• Excited States
• NIR Emission
• Pt-II Complexes

The exploration of deactivation mechanisms for near-infrared(NIR)-emissive organic molecules has been a key issue in chemistry, materials science and molecular biology. In this study, based on transient absorption spectroscopy and transient grating photoluminescence spectroscopy, we demonstrate that the aggregated Pt-II complex 4H (efficient NIR emitter) exhibits collective out-of-plane motions with a frequency of 32 cm(-1) (0.96 THz) in the excited states. Importantly, similar THz characteristics were also observed in analogous Pt-II complexes with prominent NIR emission efficiency. The conservation of THz motions enables excited-state deactivation to proceed along low-frequency vibrational coordinates, contributing to the suppression of nonradiative decay and remarkable NIR emission. These novel results highlight the significance of excited-state vibrations in nonradiative processes, which serve as a benchmark for improving device performance.

• 单位
  y; 清华大学; 中国科学院