Efficient Solar Cells from Semi-random P3HT Analogues Incorporating Diketopyrrolopyrrole

Citations Over TimeTop 1% of 2011 papers

Abstract

Three novel semi-random poly(3-hexylthiophene) (P3HT) based donor–acceptor copolymers containing 5–15% of the acceptor diketopyrrolopyrrole (DPP) were synthesized by Stille copolymerization and their optical, electrochemical, charge transport and photovoltaic properties were investigated. Poly(3-hexylthiophene-thiophene-diketopyrrolopyrrole) polymers with various percentages of DPP, represented as P3HTT-DPP-5%, P3HTT-DPP-10%, and P3HTT-DPP-15%, had high molecular weights (Mn 17 500–24 500 g/mol) and broad, intense absorption spectra, covering the spectral range from 350 nm up to 850 nm with absorption maxima at 685 and 703 nm for P3HTT-DPP-10% and P3HTT-DPP-15%. The low content of acceptor units allowed preservation of many important properties of P3HT, among which are semicrystallinity (as verified by GIXRD) and high hole mobilities (μh = (1–2.3) × 10–4 cm2/(V s)). Photovoltaic devices fabricated from P3HTT-DPP polymers blended with PC61BM showed higher short-circuit current densities (Jsc) of 9.57 – 13.87 mA/cm2 compared to P3HT (9.49 mA/cm2), leading to average power conversion efficiencies of 3.6–4.9%, which exceed the average value of 3.4% for P3HT under AM 1.5G illumination (100 mW/cm2). External quantum efficiency (EQE) measurements revealed a strong photoresponse from the semirandom polymers up to 850 nm, with EQE values above 40% across the visible and into the near-infrared for P3HTT-DPP-10% and P3HTT-DPP-15%. These results indicate that semi-random P3HT analogues provide a simple and effective route toward polymers with a broad photocurrent response in bulk heterojunction solar cells.

Related Papers

• → A facile strategy to enhance absorption coefficient and photovoltaic performance of two-dimensional benzo[1,2-b:4,5-b′]dithiophene and thieno[3,4-c]pyrrole-4,6-dione polymers via subtle chemical structure variations(2013)38 cited
• → Strong Efficiency Enhancement of Dye-Sensitized Solar Cells Using a La-Modified TiCl₄ Treatment of Mesoporous TiO₂ Electrodes(2011)32 cited
• → Soluble functionalised fullerenes for photovoltaics(2011)11 cited
• → Regioregular polymers containing benzodithiophene and thienothiophene segments with different electron donating side chains for high-performance polymer solar cells(2018)6 cited
• → An External Quantum Efficiency Model of Organic Phototransistors Excluding Photocurrent Amplification Effect(2021)2 cited