Naphthalene as a Thermal-Annealing-Free Volatile Solid Additive in Non-Fullerene Polymer Solar Cells with Improved Performance and Reproducibility

摘要

Highly volatile solid additives have attracted much attention recently becausethey enhance molecular packing order and possibly solve the problems ofpoor reproducibility and instability of polymer solar cells (PSCs) with solventadditives. The shortcoming is that existing solid additives require thermalannealing (TA) to remove them from the active layer, leading to an increase inthe complexity of the device fabrication process and morphology rearrangementproblems. This study introduces a commercially available, low-cost, andhighly volatile material, naphthalene (NA), as a solid additive used in PSCsbased on PM6: Y6. NA is well mixed with a non-fullerene acceptor and canrestrict excessive aggregation of the donor and acceptor, producing efficienciescomparable to PSCs processed by 1-chloronaphthalene (CN) solventadditive. As a result, a maximum power conversion efficiency (PCE) of 16.52%for NA-processed PSC is achieved, higher than that of a PCE of 16.07% forCN-processed PSC with TA. NA-processed PSCs exhibit comparable efficiencies(PCE of 16.10%) without TA treatment and higher reproducibility/stabilitythan CN-processed PSCs. This study demonstrates a low-cost and excellentvolatile solid additive to improve the device performance and the potential forexploring new solid additives that can readily be made volatile without TA.