Benzo[1,2-b:4,5-b′]dithiophene and Thieno[3,4-c]pyrrole-4,6-dione Based Donor-π-Acceptor Conjugated Polymers for High Performance Solar Cells by Rational Structure Modulation

Abstract

A series of benzo­[1,2-b:4,5-b′]­dithiophene and thieno­[3,4-c]­pyrrole-4,6-dione (BDT-TPD) based copolymers (P1–P4) with D-π-A structures are designed and synthesized. When the π bridges change from 2,2′-bithiophene to thieno­[3,2-b]­thiophene and then to 3-hexylthieno­[3,2-b]­thiophene, the performance of the polymer photovoltaic devices shows significant improvement. Especially, the device based on P4 with alkylthienyl-substituted BDT and π bridge of 3-hexylthieno­[3,2-b]­thiophene exhibits power conversion efficiency as high as 7.71%, and the short-circuit current of the cells is up to 13.70 mA cm–2. The results indicate that the modulation of π bridges is a feasible way to achieve highly efficient polymer solar cells.

Thieno[3,2‐b]thiophene‐Bridged Conjugated Polymers Based on Dithieno[3,2‐b:2′,3′‐d]silole and Thieno[3,4‐c]pyrrole‐4,6‐dione for Polymer Solar Cells: Influence of Side Chains on Optoelectronic Properties

“…The monomers 1,3‐bis(5‐bromo‐thieno[3,2‐ b ]thiophen‐2‐yl)‐5‐(2‐octyldodec‐yl)‐4 H ‐thieno[3,4‐ c ]pyrrole‐4,6(5 H )‐dione ( A1 ) and 1,3‐bis‐(5‐bromo‐6‐hexylthieno[3,2‐ b ]thiophen‐2‐yl)‐5‐(2‐octyldodec‐yl)‐4 H –thieno[3,4‐ c ]pyrrole‐4,6(5 H )‐dione ( A2 ) were synthesized according to the reported literature . Compounds P5 and P6 were prepared by palladium catalyzed Stille polymerization between A1 / A2 and 4,4‐dioctyl‐2,6‐bis(trimethylstannyl)‐4 H ‐silolo[3,2‐ b :4,5‐ b ′]dithiophene ( B1 ), respectively ( Scheme 2 ).…”

“…A high PCE of 7.05% was obtained in the PSCs with a thieno[3,2‐ b ]thiophene‐bridged polymer P(BDT‐TT‐BO) as donor . In our previous report, thieno[3,2‐ b ]thiophene (TT) bridge has been proved to be able to enhance the hole mobility and the optoelectronic performances in the BDT‐TPD‐based polymers . It has been demonstrated that the light absorption, energy levels, charge transport, and photovoltaic performances can be efficiently adjusted by introducing different π bridges .…”

Efficiency enhancement in an indacenodithiophene and thieno[3,4-c]pyrrole-4,6-dione backbone photovoltaic polymer with an extended thieno[3,2-b]thiophene π-bridge

“…[39,41] Monomer IDT-di-Tin was purchased from SunaTech Inc. [39,41] Monomer IDT-di-Tin was purchased from SunaTech Inc.…”

“…[15,22,[27][28][29][30][31][32][33] Replacing the outward thiophene moiety of IDT with extended thieno[3,2-b]thiophene (TT) unit or inserting πbridges such as thiophene or TT between IDT donor and acceptor units have been proven to be effective strategies to extend π-conjugated system of IDT backboned polymers. [39] Therefore, further rational design and detailed investigation of the length on π-conjugated backbone would be necessary to obtain desirable organic photovoltaic materials. Nevertheless, proper attention needs to be paid to the solubility problems caused by extended fusion, which would cause negative impacts on coating and film morphology.…”

Triisopropylsilylacetylene-functionalised anthracene-alt-benzothiadiazole copolymers for application in bulk heterojunction solar cells

“…[28][29][30][31][32] Park et al reported a new class of anthracene-thiophene based copolymers incorporating bulky triisopropylsilylacetylene (TIPS) groups at the 9,10-positions of the anthracene moiety. 32 It was reported that the incorporation of TIPS groups overcame the poor charge transportation properties and high crystallinity that are generally associated with polythiophene-based copolymers.…”