Efficient polymer solar cells utilizing solution‐processed interlayer based on different conjugated backbones

Abstract

The poor energy conversion efficiency for those polymer solar cells (PSCs) creates an obstacle for their commercialization. Inspired by this issue, two cathode interlayers, PBTBTz‐TMAI and PBTzPh‐TMAI based on benzothiadiazole (BT) and benzotriazole (BTz)‐conjugated or benzene (Ph) and BTz‐conjugated alternating units (both exhibits the same tetravalent amine‐end side chain), were synthesized via Suzuki coupling polymerization and trivalent amine‐end ionization. When PBTBTz‐TMAI and PBTzPh‐TMAI were utilized as cathode interlayers in PSCs, the charge‐carrier transfer from active layer to cathode electrode was significantly improved, accompanied by an optimized exciton dissociation efficiency, primarily attributed to the introduction of tetravalent amine groups. Consequently, the device with PBTBTz‐TMAI exhibited power conversion efficiencies (PCEs) = 8.3 and 10.5% for the PTB7:PC71BM‐based and PBDB‐T:ITIC‐based PSCs, respectively. In parallel, devices with a PBTzPh‐TMAI cathode interlayer (that were established on the active layers of PTB7:PC71BM and PBDB‐T:ITIC) obtained a remarkably superior optoelectric efficiency with PCEs = 8.5 and 10.8%. These findings offer an alternative tactic toward to high efficiency PSCs to meet the increasing energy crisis.

Conjugated Polyelectrolyte‐Based Complex Fluids as Aqueous Exciton Transport Networks

“…Among the materials synthesized for such efforts, organic semiconductors possess the advantages of being light‐weight, highly tunable, and inexpensive to process. Major efforts have been undertaken to make new materials for organic photovoltaic devices [1–9] . Recently, much work has gone into the use of self‐assembly to form components of light‐harvesting systems, like electronic energy‐transfer antennae [10–17] .…”

“…Major efforts have been undertaken to make new materials for organic photovoltaic devices. [1][2][3][4][5][6][7][8][9] Recently, much work has gone into the use of self-assembly to form components of lightharvesting systems, like electronic energy-transfer antennae. [10][11][12][13][14][15][16][17] Here the self-assembled components are arranged through non-covalent interactions to directionally guide the transport of electronic excited states (excitons), thereby mimicking exciton transport in photosynthetic organisms.…”