Jean-Rémi Pouliot

Bulk heterojunction solar cells using thieno[3,4-c]pyrrole-4,6-dione and dithieno[3,2-b:2',3'-d]silole copolymer with a power conversion efficiency of 7.3%.

A new alternating copolymer of dithienosilole and thienopyrrole-4,6-dione (PDTSTPD) possesses both a low optical bandgap (1.73 eV) and a deep highest occupied molecular orbital energy level (5.57 eV). The introduction of branched alkyl chains to the dithienosilole unit was found to be critical for the improvement of the polymer solubility. When blended with PC(71)BM, PDTSTPD exhibited a power conversion efficiency of 7.3% on the photovoltaic devices with an active area of 1 cm(2).

Enhanced Efficiency of Single and Tandem Organic Solar Cells Incorporating a Diketopyrrolopyrrole‐Based Low‐Bandgap Polymer by Utilizing Combined ZnO/Polyelectrolyte Electron‐Transport Layers

Power conversion efficiency up to 8.6% is achieved for a solution-processed tandem solar cell based on a diketopyrrolopyrrole-containing polymer as the low-bandgap material after using a thin polyelectrolyte layer to modify the electron-transport ZnO layers, indicating that interfacial engineering is a useful approach to further enhancing the efficiency of tandem organic solar cells.

Synthesis of new n-type isoindigo copolymers

Three new n-type copolymers were synthesized using the isoindigo monomer. 5-Octylthieno[3,4-c]pyrrole-4,6-dione (TPD), 5,5′-dioctyl-1,1′-4H-bithieno[3,4-c]pyrrole-4,4′,6,6′(5H,5′H)-tetrone (BTPD) and 3,6-bis(thiophen-2-yl)-2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) were utilized as electron-withdrawing comonomers to obtain reduced or low bandgap n-type copolymers with deep HOMO and LUMO energy levels. The TPD and BTPD copolymers were synthesized using direct arylation polymerization and show bandgaps of 1.72 and 1.75 eV, respectively. Their LUMO and HOMO energy levels are also low at −4.2 and −6.0 eV, respectively. We investigated their electron mobility using thin film transistors and achieved electron mobility as high as 3.0 × 10−4 and 3.5 × 10−3 cm2 s−1 V−1 for the TPD and BTPD copolymers. The DPP copolymer was synthesized using Suzuki conditions and shows a low bandgap of 1.35 eV and a low LUMO energy level of −4.0 eV. The DPP copolymer exhibits an electron mobility of 2.7 × 10−4 cm2 s−1 V−1. All these polymers show interesting properties as potential electron acceptors in all-polymer solar cells.

A high mobility DPP-based polymer obtained via direct (hetero)arylation polymerization

Many diketopyrrolopyrrole-based (DPP) polymers have shown remarkable transport properties and to fabricate cost efficient materials, the new direct (hetero)arylation polymerization (DHAP) could become a valuable tool. Although the DHAP offers great promise for more efficient, atom-economic and cheaper aromatic C–C bond formations, this method seems to involve a lack of selectivity. Herein, we report an alternating DPP-based copolymer prepared by DHAP that shows a well-defined structure. A rational side-chain design of the comonomers led to a polymer that exhibits a high molecular weight along with excellent charge transport properties (p-type mobility up to 1.17 cm2 V−1 s−1).

Synthesis and Characterization of 5-Octylthieno[3,4-c]pyrrole-4,6-dione Derivatives As New Monomers for Conjugated Copolymers

An efficient route for the synthesis of 1-iodo-5-octyl-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione as a key intermediate to build new electron-deficient monomers and related conjugated polymers is reported. Along these lines, two new low bandgap copolymers were synthesized from Stille or Suzuki coupling. These polymers were characterized and their properties compared to those of analogous conjugated polymers.

Easy and versatile synthesis of new poly(thieno[3,4-d]thiazole)s

New alternating copolymers based on thieno[3,4-d]thiazole (TTz) derivatives were synthesized by Stille, Suzuki or direct (hetero)arylation polycondensation (DHAP) reactions using either benzodithiophene (BDT), dithienosilole (DTS), thieno[3,4-c]pyrrole-4,6-dione (TPD), diketopyrrolopyrrole-1,4-dione (DPP) or isoindigo units as comonomers. In particular, the direct hetero(arylation) polycondensation reaction has been shown to be a very interesting tool for a more efficient and economical access to new conjugated polymers. Modifications of the TTz moiety and of the polymer backbone show that it is possible to efficiently modulate the HOMO and LUMO energy levels of TTz-based copolymers. These conjugated polymers exhibit bandgaps between 1.07 and 1.82 eV with HOMO energy levels ranging from −5.06 to −5.48 eV and LUMO energy levels ranging from −3.61 to −4.02 eV.