New Electron Acceptor with End-Extended Conjugation for High-Performance Polymer Solar Cells
Artikel i vetenskaplig tidskrift, 2021

To develop high-efficiency polymer solar cells (PSCs), the acceptors in a bulk heterojunction (BHJ) blend are supposed to possess complementary absorption bands in the near-infrared region and a suitable energy level to be well-matched with the donors. In this work, a new small molecular acceptor (SMA) named IDTT8-N based on an indacenodithienothiophene (IDTT) core was designed and synthesized. In comparison to the counterpart molecule IDTN with an indacenodithiophene (IDT) core, IDTT8-N with the extended π-conjugation length of an IDT core not only exhibits a red shift of ca. 35 nm in optical absorption but also has little change on its lowest unoccupied molecular orbital (LUMO) energy level. Therefore, PSCs based on PM6:IDTT8-N exhibit a superior short-circuit current density (Jsc) and high open-circuit voltage (Voc). Moreover, apart from the strong face-on molecular stacking, distinct end-group π-πstacking of IDTT8-N can be observed in the blends, facilitating the charge transport. Therefore, the optimized PM6:IDTT8-N-based devices exhibit dramatically high and balanced electron mobility (μe) and hole mobility (μh), whose magnitudes are over 10-3 cm2 V-1 s-1. Consequently, an extraordinary PCE of 14.1% with a relatively high Jsc of 20.98 mA cm-2 and a Voc of 0.94 V was recorded. To our knowledge, it is the new record among PSCs with a SMA based on 2-(3-oxocyclopentylidene)malononitrile (INCN) as end groups. These results indicate that extending the π-conjugation length of the fused ring core of a SMA is an efficient method to both enhance the absorption and the molecular interaction of the acceptor as well as the photovoltaic performance of PSCs.

Författare

Jingnan Wu

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Ergang Wang Group

Soochow University

Aalborg Universitet

Qi Liu

Soochow University

Long Ye

North Carolina State University

Xia Guo

Soochow University

Hong Kong Polytechnic University

Qunping Fan

Soochow University

Junfang Lv

Soochow University

Maojie Zhang

Soochow University

Wai Yeung Wong

Hong Kong Polytechnic University

Energy & Fuels

0887-0624 (ISSN) 1520-5029 (eISSN)

Vol. In Press

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Ämneskategorier

Atom- och molekylfysik och optik

Teoretisk kemi

Den kondenserade materiens fysik

DOI

10.1021/acs.energyfuels.1c02470

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Senast uppdaterat

2021-11-09