Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
Publication date: 11th July 2022
Power conversion efficiencies (PCEs) of bulk heterojunction (BHJ) organic solar cells (OSCs) continue increasing towards the 20% milestone mainly thanks to the emerging non-fullerene acceptors (NFAs). Nevertheless, important factors for industrial application are mostly neglected, such as photostability and cost potential. Single-component organic solar cells (SCOSCs) employing materials with donor and acceptor moieties chemically bonded within one molecule or polymer, successfully overcome the immiscibility between donor and acceptor as well as the resultant self-aggregation under external stress [1]. To inspire a broader interest, in this work, the industrial figure of merit (i-FOM) of OSCs is calculated and analyzed, which includes PCE, photostability, and synthetic complexity (SC) index [2]. Based on the notable advantages of SCOSCs over the correspondent BHJ OSCs, especially the enhanced stability and simplified film processing, we systematically compare the i-FOM values of BHJ OSCs and the corresponding SCOSCs.
SCMs exhibit overall much higher i-FOM values compared with the BHJ OSCs, and the highest value reaches 0.3, which is even higher than the famous PM6:Y6, even though the PCE (8%) is only half of PM6:Y6. With the increase in efficiency, SCOSCs possess the further potential for a higher i-FOM value. Among all factors, the synthetic complexity of SCOSCs is slightly higher than that of the corresponding BHJ OSCs due to the extra synthetic step for connecting donor and acceptor moieties. This feature however overcomes the large-scale phase separation and stability issue for the corresponding BHJ systems [3]. SCOSCs based on dyad 1 exhibit surprisingly high photostability under concentrated light (7.5 suns and 30 suns), corresponding to almost unchanged device stability up to 10,000 hours under 1-sun illumination. For realizing industrial application, SCOSCs have to give a high efficiency comparable to the current high-efficiency BHJ OSCs, while BHJ should be developed in the direction of less complicated synthesis [4]. With joint efforts of researchers from multidiscipline, SCOSCs will see continuing progress in efficiency, reaching an i-FOM value enough for industrial application.
Y. He is grateful for the financial support from China Scholarship Council (CSC) and the Erlangen Graduate School in Advanced Optical Technologies (SAOT). C.J.B. gratefully acknowledges the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the project numbers 182849149 – SFB 953, INST 90/917, and INST 90/1093-1; financial support through the “Aufbruch Bayern” initiative of the state of Bavaria (EnCN and SFF) and the Bavarian Initiative “Solar Technologies go Hybrid” (SolTech); and the grant “ELF-PV Design and development of solution processed functional materials for the next generations of PV technologies” by the Bavarian State Government (no. 44-6521a/20/4). W.L. is grateful for the support of Beijing Natural Science Foundation (JQ21006). N.L. acknowledges the financial support by State Key Lab of Luminescent Materials and Devices, South China University of Technology (Skllmd-2022-03).