Low-Band-Gap Small Molecule for Efficient Organic Solar Cells with a Low Energy Loss below 0.6 eV and a High Open-Circuit Voltage of over 0.9 V

作者：Yang Daobin; Sasabe Hisahiro; Sano Takeshi; Kido Junji

来源：ACS Energy Letters, 2017, 2(9): 2021-2025.

DOI：10.1021/acsenergylett.7b00608

Small molecule organic solar cells (SMOSCs) have received considerable attention in recent years. However, one of the key factors limiting the performance of SMOSCs is their large energy loss (E-loss,), which is typically between 0.6 and 1.0 eV, and therefore significantly higher than those of perovskite solar cells and inorganic solar cells (E-loss < 0.5 eV). Herein, we successfully report a new acceptor-donor-acceptor (A-D-A) type dimeric squaraine electron donor (D-IDTT-SQ) with a low optical band gap of 1.49 eV and deep HOMO energy level of -5.20 eV. Consequently, a high open-circuit voltage (Voc) of 0.93 V with an impressive power conversion efficiency (PCE) of 7.05% is achieved for solution-processed bulk heterojunction SMOSCs, showing an E-loss, of only 0.56 eV. This is the first report wherein SMOSCs result in such a low 45, while simultaneously exhibiting a considerably high V-oc over 0.9 V and an excellent PCE above 7.0%.

• 出版日期2017-9