Direct Measurements of Intersystem Crossing Rates and Triplet Decays of Luminescent Conjugated Oligomers in Solutions

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• 作者：Hsin-Liang Chen ; Yi-Fang Huang ; Chao-Ping Hsu ; Tsong-Shin Lim ; Li-Chung Kuo ; Man-kit. Leung ; Teng-Chih Chao ; Ken-Tsung Wong ; Show-An Chen ; Wunshain Fann
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：September 27, 2007
• 年：2007
• 卷：111
• 期：38
• 页码：9424 - 9430
• 全文大小：194K
• 年卷期：v.111,no.38(September 27, 2007)
• ISSN：1520-5215

文摘

Photothermal calorimetry and fluorescence spectroscopy were used to determine the relaxations of thephotoexcited singlet state of two PPV and polyfluorene oligomers, (E,E)-1,4-bis[(2-benzyloxy)styryl]benzene(PVDOP) and ter(9,9'-spirobifluorene) (TSBF). The decay rates of different S₁ relaxation channels, whichinclude intersystem crossing (ISC), radiative, and nonradiative decay can be determined by the combinationof photoacoustic calorimetry (PAC) and the time-correlated single photon counting (TCSPC) technique. Thetriplet state energy level is determined by the phosphorescence (Ph) spectra recorded at 77 K. The ISC yieldsare ~3% and 6% for PVDOP and TSBF, respectively. The T₁ to S₀ transition decay rate is acquired by PACand photothermal beam deflection (PBD) measurements. The triplet state decay rate is 17 and 21 ms^-1 atroom temperature. The Ph intensity decay at 77 K shows that the triplet state lifetime increases by 4 ordersof magnitude, as compared to room temperature.