AI Article Synopsis
- Recent advances in conjugated polymers have focused on developing low band gap materials for photovoltaic devices, but other performance factors are also crucial.
- This research introduces two medium band gap copolymers, particularly PBnDT-FTAZ, which provides high hole mobility and specific energy levels, achieving over 7% efficiency in bulk heterojunctions.
- PBnDT-FTAZ outperforms the widely used poly(3-hexylthiophene) and showcases additional performance criteria essential for enhancing photovoltaic efficiency.
Article Abstract
Recent research advances on conjugated polymers for photovoltaic devices have focused on creating low band gap materials, but a suitable band gap is only one of many performance criteria required for a successful conjugated polymer. This work focuses on the design of two medium band gap (~2.0 eV) copolymers for use in photovoltaic cells which are designed to possess a high hole mobility and low highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. The resulting fluorinated polymer PBnDT-FTAZ exhibits efficiencies above 7% when blended with [6,6]-phenyl C(61)-butyric acid methyl ester in a typical bulk heterojunction, and efficiencies above 6% are still maintained at an active layer thicknesses of 1 μm. PBnDT-FTAZ outperforms poly(3-hexylthiophene), the current medium band gap polymer of choice, and thus is a viable candidate for use in highly efficient tandem cells. PBnDT-FTAZ also highlights other performance criteria which contribute to high photovoltaic efficiency, besides a low band gap.
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