Triplet Exciton Diffusion in Platinum Polyyne Films

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• 作者：Hsien-Yi Hsu ; Jarrett H. Vella ; Jason D. Myers ; Jiangeng Xue ; Kirk S. Schanze
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：October 23, 2014
• 年：2014
• 卷：118
• 期：42
• 页码：24282-24289
• 全文大小：357K
• ISSN：1932-7455

文摘

A time-resolved photoluminescence quenching approach is developed for determining the triplet exciton diffusion coefficient and diffusion length (D and L_D, respectively) of phosphorescent conjugated polymers. This method is applied to a solid-state organometallic conjugated polymer with the structure [鈭扨t(PBu₃)₂鈥揅C鈥揅₆H₄鈥揅C鈭抅_n (where Bu = n-butyl and 鈭扖₆H₄鈥?is 1,4-phenylene). The approach relies on analysis of the lifetime quenching of the polymer鈥檚 phosphorescence by a series of three different quenchers that are dispersed into the polymer phase at varying concentration. The lifetime quenching data are analyzed by using a modified Stern鈥揤olmer quenching expression to determine the diffusion-controlled quenching rate constant, k_q, which is then related to the exciton diffusivity, D, and diffusion length, L_D. The diffusion coefficients that are determined using the three quenchers are consistent, D 鈮?4 脳 10^鈥? cm² s^鈥?, and combined with the triplet exciton lifetime of the pristine polymer (蟿 = 1.05 渭s) give an exciton diffusion length L_D 鈮?22 nm. The results are compared to literature studies of singlet exciton diffusion in conjugated polymers and triplet exciton diffusion in molecular materials.