Atomistic Insight Into Donor/Acceptor Interfaces in High‐Efficiency Nonfullerene Organic Solar Cells. Issue 11 (4th September 2018)

• Record Type: Journal Article
• Authors: Han, Guangchao; Guo, Yuan; Ma, Xiaoyi; Yi, Yuanping
• Is Part Of: Solar RRL. Volume 2:Issue 11(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-04
• Subjects: atomistic simulations -- charge transfer -- D/A interfaces -- nonfullerene acceptors; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201800190
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Donor/acceptor (D/A) interfaces play a crucial role in photoelectric conversion for organic solar cells. However, it is impossible to experimentally probe D/A interfaces at the atomistic level to date, in particular for organic solar cells based on nonfullerene acceptors due to their anisotropic structures. In this work, we have investigated the interfacial structures of a representative D‐A copolymer donor PBDB‐T with a well‐known A‐D‐A structured nonfullerene acceptor ITIC, in comparison with a fullerene acceptor PC71 BM, by means of atomistic simulations. It is found that owing to different side‐chain steric hindrance between the polymer A and D units, both acceptors are more likely to approach the polymer A units, and more apparently for ITIC in consideration of the size and shape matching between the acceptors and the polymer A and D units. Importantly, docking of ITIC with polymer occurs mainly through local π–π interaction between the terminal moieties of ITIC and the A units of the polymer, and such interfacial structures are favorable for efficient exciton dissociation. Our work sheds light on the impact of side‐chain nature and location as well as acceptor structures on D/A interfaces and charge‐transfer dynamics, which will be very helpful for further improving the performance of organic photovoltaics. Abstract : Intermolecular arrangements of PBDB‐T with ITIC and PC71BM are revealed by atomistic simulations. Owing to smaller side‐chain steric hindrance, both acceptors are prone to approach polymer A units, especially for ITIC considering better matching in size and shape. Importantly, PBDB‐T/ITIC docking occurs mainly via local π–π interaction between electron‐withdrawing end groups of ITIC and A units of the polymer, which is beneficial for efficient exciton dissociation.