Volume 62, Issue 16 e202300815
Research Article

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

Yu-Chen Wei

Yu-Chen Wei

Department of Chemistry, National Taiwan University, Taipei, 10617 Taiwan

Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617 Taiwan

These authors contributed equally to this work.

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Bo-Han Chen

Bo-Han Chen

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

These authors contributed equally to this work.

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Ren-Siang Ye

Ren-Siang Ye

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

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Hsing-Wei Huang

Hsing-Wei Huang

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

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Jia-Xuan Su

Jia-Xuan Su

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

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Chao-Yang Lin

Chao-Yang Lin

Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, 6012 New Zealand

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Justin Hodgkiss

Justin Hodgkiss

MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6010 New Zealand

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Lian-Yan Hsu

Lian-Yan Hsu

Department of Chemistry, National Taiwan University, Taipei, 10617 Taiwan

Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617 Taiwan

National Center for Theoretical Sciences, Taipei, 10617 Taiwan

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Yun Chi

Corresponding Author

Yun Chi

Department of Materials Science and Engineering, Department of Chemistry, and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, Hong Kong

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Kai Chen

Corresponding Author

Kai Chen

Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, 6012 New Zealand

MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6010 New Zealand

The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, 9016 New Zealand

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Chih-Hsuan Lu

Corresponding Author

Chih-Hsuan Lu

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

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Shang-Da Yang

Corresponding Author

Shang-Da Yang

Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013 Taiwan

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Pi-Tai Chou

Corresponding Author

Pi-Tai Chou

Department of Chemistry, National Taiwan University, Taipei, 10617 Taiwan

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First published: 23 February 2023
Citations: 8
**

A previous version of this manuscript has been deposited on a preprint server (https://doi.org/10.21203/rs.3.rs-2118385/v1).

Graphical Abstract

A series of aggregate PtII complexes exhibits low-frequency (THz) excited-state vibrations measured by femtosecond-resolved transient absorption spectroscopy and transient grating photoluminescence spectroscopy. These significant low-frequency vibronic displacements suppress non-radiative decay and enhance near-infrared emission efficiencies.

Abstract

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 PtII 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 PtII 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.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.