Synthetically facile organic solar cells with >4% efficiency using P3HT and a silicon phthalocyanine non-fullerene acceptor

We demonstrate organic photovoltaic devices with extremely low synthetic complexity by pairing poly(3-hexithiophene) (P3HT) with a novel non-fullerene acceptor (NFA) bis(tri-n-propylsilyl oxide) silicon phthalocyanine ((3PS)2-SiPc). (3PS)2-SiPc possesses a relatively unique combination of high solubility and excellent thermal stability, facilitating its ease of processing by both solution and sublimation techniques. Binary P3HT/(3PS)2-SiPc devices achieved an average power conversion efficiency of 4.3%, a new record for SiPc NFAs. AFM and synchrotron STXM measurements reveal a unique morphology of P3HT/(3PS)2-SiPc, with significant phase separation due to the strong crystallization of (3PS)2-SiPc.