Design and synthesis of carbonyl group modified conjugated polymers for photovoltaic application

Abstract

In this article, a simple and common electron-withdrawing moiety, carbonyl group, is applied in the molecular design of conjugated polymers for highperformance polymer solar cells (PSCs). Two series of donor-acceptor (D-A) copolymers are synthesized through alternating copolymerization of the electrondonating (D) benzodithiophene and dithienopyrrole with various electron-accepting (A) units containing carbonyl groups. The absorption range and the band gap of copolymers can be tuned by changing the molecular structure of A unit and the number of carbonyl groups. Moreover, by introducing the carbonyl group, the highest occupied molecular orbital energy level of the copolymer is lowered efficiently, leading to the improvement of the open-circuit voltage (V OC ) of PSCs. The best photovoltaic performance is obtained while poly(benzodithiophene-alt-thiophene-3-carboxylate) is functioned as the electron donor and [6,6]-phenyl-C 61 -butyric acid methyl ester as electron acceptor in a bulk heterojunction solar cell with a power conversion efficiency of 4.13%, a V OC of 0.80 V, a short-circuit current of 8.19 mA/cm 2 , and a fill factor of 63.2%.

Efficient Polymer Solar Cells With High Fill Factor Enabled by A Furo[3,4‐c]pyrrole‐4,6‐dione‐Based Copolymer

“…The exceptional energy level variation is associated with the configuration of polymers. And the similar situation was also found for other copolymers …”

Novel Approaches in the Design of Donor-Acceptor Oligomeric and Polymeric Materials for Photovoltaic Applications: D/A Blend versus Self-assembly of D/A by Covalent or Non-Covalent Interaction

“…By adding DIO as a solvent additive to optimize the mixing morphology of the P3HT: NDI-21 combination, the PCE and fill factor (FF) reached values of 1.63% and 0.66, respectively. Apartfrom this, several other NDI based donor-acceptor alternating polymers incorporating a variety of donors have been reported and implemented in solar cell devices; however their power conversion efficiencies were not very encourageable [79][80][81][82]. Zheng and co-workers reported three new building blocks of angular shaped NDI polymers as an acceptor with increasing number of thiophene as donor units (1-3) structure NDI-22.…”

Enhanced performance of polymer solar cells with a monolayer of assembled gold nanoparticle films fabricated by Langmuir–Blodgett technique

“…Bulk-heterojunction (BHJ) polymer solar cells have witnessed dramatic progress either by developing new materials or engineering device structure during the past decade, with lab power conversion efficiency (Á p ) over 8% reported recently [1][2][3][4][5][6][7][8][9]. The photocurrent of a polymer solar cell is largely determined by its absorption efficiency (Á A ) and internal quantum efficiency (Á IQE ) [10,11].…”