Energetics of Electron鈥揌ole Separation at P3HT/PCBM Heterojunctions
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- 作者：Gabriele D鈥橝vino ; S茅bastien Mothy ; Luca Muccioli ; Claudio Zannoni ; Linjun Wang ; J茅r么me Cornil ; David Beljonne ; Fr茅d茅ric Castet
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：June 27, 2013
- 年：2013
- 卷：117
- 期：25
- 页码：12981-12990
- 全文大小：541K
- 年卷期：v.117,no.25(June 27, 2013)
- ISSN：1932-7455
文摘
The energetics of electron鈥揾ole separation at the prototypical donor鈥揳cceptor interface P3HT/PCBM is investigated by means of a combination of molecular dynamics simulations, quantum-chemical methods, and classical microelectrostatic calculations. After validation against semiempirical Valence Bond/Hartree鈥揊ock results, microelectrostatic calculations on a large number of electron鈥揾ole (e-h) pairs allowed a statistical study of charge separation energetics in realistic morphologies. Results show that charge separation is an energetically favorable process for about 50% of interfacial e-h pairs, which provides a rationale for the high internal quantum efficiencies reported for P3HT/PCBM heterojunctions. Three effects contribute to overcome the Coulomb attraction between electron and hole: (i) favorable electrostatic landscape across the interface, (ii) electronic polarization, and (iii) interface-induced torsional disorder in P3HT chains. Moreover, the energetic disorder due to the PCBM polar group is shown to play a key role in increasing the dissociation probability.