Fürk P, Hofinger J, Reinfelds M, Rath T, Amenitsch H, Scharber MC, Trimmel G. Glycol bearing perylene monoimide based non-fullerene acceptors with increased dielectric permittivity.
MONATSHEFTE FUR CHEMIE 2022;
154:1369-1381. [PMID:
38020486 PMCID:
PMC10667137 DOI:
10.1007/s00706-022-02956-2]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/27/2022] [Indexed: 10/16/2022]
Abstract
Perylene monoimide based electron acceptors have great properties for use in organic solar cells, like thermal stability, strong absorption, and simple synthesis. However, they typically exhibit low values for the dielectric permittivity. This hinders efficient exciton dissociation, limiting the achievable power conversion efficiencies. In this work, we present the synthesis and utilization of two new acceptor-donor-acceptor (A-D-A) molecules, comprising perylene monoimide as electron withdrawing A unit. Oligo ethylene glycol side chain modified carbazole (PMI-[C-OEG]) and fluorene (PMI-[F-OEG]) linkers were used as electron rich D units, respectively. The polar side chains are expected to increase the polarizability of the molecules and, thus, their permittivity according to the Clausius-Mossotti relationship. We found that the incorporation of glycol chains improved the dielectric properties of both materials in comparison to the reference compounds with alkyl chains. The permittivity increased by 18% from 3.17 to 3.75 for the carbazole-based non-fullerene acceptor PMI-[C-OEG] and by 12% from 3.10 to 3.47 for the fluorene-based acceptor PMI-[F-OEG]. The fabricated solar cells revealed power conversion efficiencies of 3.71 ± 0.20% (record 3.92%) with PMI-[C-OEG], and 1.21 ± 0.06% (record 1.51%) with PMI-[F-OEG].
Graphical abstract
Supplementary Information
The online version contains supplementary material available at 10.1007/s00706-022-02956-2.
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