Probing Triplet Excited States and Managing Blue Light Emission of Neutral Tetradentate Platinum(II) Complexes

Cong You; Fang Xia; Yue Zhao; Yin Zhang; Yongjian Sheng; Yipei Wu; Xiao-Chun Hang; Fei Chen; Huili Ma; Kang Shen; Zhengyi Sun; Takahiro Ueba; Satoshi Kera; Cong Zhang; Honghai Zhang; Zhi-Kuan Chen; Wei Huang

doi:10.1021/acs.jpclett.8b00797

Probing Triplet Excited States and Managing Blue Light Emission of Neutral Tetradentate Platinum(II) Complexes

J Phys Chem Lett. 2018 May 3;9(9):2285-2292. doi: 10.1021/acs.jpclett.8b00797. Epub 2018 Apr 19.

Authors

Cong You¹, Fang Xia¹, Yue Zhao¹, Yin Zhang¹, Yongjian Sheng¹, Yipei Wu¹, Xiao-Chun Hang¹, Fei Chen¹, Huili Ma¹, Kang Shen¹, Zhengyi Sun¹, Takahiro Ueba², Satoshi Kera², Cong Zhang¹, Honghai Zhang¹, Zhi-Kuan Chen¹, Wei Huang^{1

3}

Affiliations

¹ Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM) , Nanjing Tech University (NanjingTech) , 30 South Puzhu Road , Nanjing 211800 , China.
² Department of Photo-Molecular Science , Institute for Molecular Science , Okazaki , Aichi 444-8585 , Japan.
³ Shaanxi Institute of Flexible Electronics (SIFE) , Northwestern Polytechnical University (NPU) , 127 West Youyi Road , Xi'an 710072 , China.

PMID: 29664638
DOI: 10.1021/acs.jpclett.8b00797

Abstract

The structural and photophysical properties of tetradentate Pt(ppzOppz), Pt(ppzOpopy), Pt(ppzOczpy), and Pt(czpyOczpy) have been experimentally and theoretically explored. Single-crystal diffraction measurements provided accurate structural information. Electrochemical and photophysical characterizations revealed internal electronic energy levels in ground and excited states. (Time-dependent) Density functional theory calculation revealed electron distributions in transition processes of S₀ → S₁ and S₁ → T₁ → S₀. Electronic transition study indicated that Pt(ppzOppz) demonstrated mixed MLCT/LC states and Pt(czpyOczpy) showed MLCT-dominated states in S₁ and T₁. Both Pt(ppzOpopy) and Pt(ppzOczpy) presented strong delocalized spin transition (DST) during intersystem crossing. Upon frame modification of Pt(ppzOczpy), we found that their S₁ and T₁ can be independently manipulated. These blue emitters showed a tunable and narrow emission band (the narrowest fwhm was 19 nm) with luminescence efficiency as high as 86%. The findings of the DST transition mode in the neutral Pt(II) complexes provide guidance for rational design of novel phosphorescent materials.