Polymer/Polymer Blend Solar Cells Using Tetraazabenzodifluoranthene Diimide Conjugated Polymers as Electron Acceptors

Abstract

Two n-type semiconducting polymers with alternating arylene (thiophene or selenophene)−tetraazabenzodifluoranthene diimide (BFI) donor−acceptor architecture have been investigated as new electron acceptors in polymer/ polymer blend solar cells. The new selenophene-linked polymer, PBFI-S, has a significantly smaller optical band gap (1.13 eV) than the thiophene-linked PBFI-T (1.38 eV); however, both polymers have similar HOMO/LUMO energy levels determined from cyclic voltammetry. Blends of PBFI-T with the thiazolothiazole−dithienylsilole donor polymer (PSEHTT) gave a 2.60% power conversion efficiency (PCE) with a 7.34 mA/cm 2 short-circuit current. In contrast, PBFI-S:PSEHTT blends had a 0.75% PCE with similarly reduced photocurrent and external quantum efficiency. Reduced free energy for charge transfer and reduced bulk electron mobility in PBFI-S:PSEHTT blends compared to PBFI-T:PSEHTT blends as well as significant differences in bulk film morphology are among the reasons for the large loss in efficiency in PBFI-S:PSEHTT blend solar cells.

Near‐infrared organic photoelectric materials for light‐harvesting systems: Organic photovoltaics and organic photodiodes

“…These building blocks have a high electron‐withdrawing ability due to the combination of nitrogen‐containing aromatic groups and the dicarboxylic acid imide functionality. Copolymerization of BFI and an arylene (thiophene or selenophene) provided the low‐bandgap copolymers PBFI‐T and PBFI‐S . Specifically, the selenophene‐linked copolymer PBFI‐S has a low bandgap of 1.13 eV.…”

Perfluoroalkyl-substituted conjugated polymers as electron acceptors for all-polymer solar cells: the effect of diiodoperfluoroalkane additives

“…There has been increasing interest in non-fullerene conjugated materials to replace fullerene derivatives as electron acceptors in organic solar cells in recent years. [1][2][3] A signicant number of conjugated small molecules [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and polymers [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] with excellent electron transport properties and aligned energy levels have been designed and synthesized, which are well-suited as electron acceptors in organic photovoltaic devices. Currently, perylenediimide and naphthalenediimide based materials are considered as the most promising non-fullerene acceptors, 36,37 since these materials have shown high electron mobilities of about 1 cm 2 V À1 s À1 (ref.…”

Photoactive Compounds Based on the Thiazolo[5,4‐d]thiazole Core and Their Application in Organic and Hybrid Photovoltaics

“…In their studies on alternative acceptors, Jenekhe and co-workers extensively explored the use of copolymer PSEHTT (Figure 4) as the donor in combination with various different naphthalene diimide derivatives, both polymers [93][94][95][96][97] and small-molecule compounds. [98][99][100] The best PCE of 6.18 % (with a high V oc of 0.92 V) was obtained with dimeric acceptor DBFI-DMT: [100] the authors explain such an excellent performance in terms of the relatively high-lying LUMO of the acceptor coupled with its particular, twisted 3D conformation, which had a positive influence on the bulk charge-transport properties of the photovoltaic devices.…”