Distance Dependence of Triplet Energy Transfer in Water and Organic Solvents: A QM/MD Study

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• 作者：Carles Curutchet ; Alexander A. Voityuk
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：October 25, 2012
• 年：2012
• 卷：116
• 期：42
• 页码：22179-22185
• 全文大小：354K
• 年卷期：v.116,no.42(October 25, 2012)
• ISSN：1932-7455

文摘

The possibility to optimize optoelectronic devices, such as organic light-emitting diodes or solar cells, by exploiting the special characteristics of triplet electronic states and their migration ability is attracting increased attention. In this study, we analyze how an intervening solvent modifies the distance dependence of triplet electronic energy transfer (TEET) processes by combining molecular dynamics simulations with quantum chemical calculations of the transfer matrix elements using the Fragment Excitation Difference (FED) method. We determine the 尾 parameter characterizing the exponential distance decay of TEET rates in a stacked perylene dimer in water, chloroform, and benzene solutions. Our results indicate that the solvent dependence of 尾 (尾_vacuum = 5.14 脜^鈥? > 尾_water = 3.77 脜^鈥? > 尾_chloroform = 3.61 脜^鈥? > 尾_benzene = 3.44 脜^鈥?) can be rationalized adopting the McConnell model of superexchange, where smaller triplet energy differences between the donor and the solvent lead to smaller 尾 constants. We also estimate the decay of hole transfer (HT) and excess electron transfer (EET) processes in the system using the Fragment Charge Difference (FCD) method and find that 尾_TEET can be reasonably well approximated by the sum of 尾_EET and 尾_HT constants.