A High‐Performance Non‐Fullerene Acceptor Compatible with Polymers with Different Bandgaps for Efficient Organic Solar Cells

Abstract

Owing to their good polymer compatibility, fullerene derivatives, such as PC 61 BM and PC 71 BM, have been the dominant electron acceptors to pair with various polymer donors in polymer solar cells (PSCs). The recent surge of non-fullerene materials leads to several high-performance molecular acceptors. Despite their high performance in a given polymer/acceptor system, the generality of these acceptors, i.e., their compatibility with different donor polymers remains uncertain. Here, a high-performance small molecule acceptor (SMA), BTTIC, is designed and synthesized to combine with three polymers with different bandgaps, namely J71 (1.92 eV), PBDB-T (1.80 eV), and PTB7-Th (1.58 eV). Complementary absorption, compatible energy levels, and particularly the favorable morphologies between BTTIC and the three polymers enable high power conversion efficiencies (PCEs), which are 12.8%, 13.2%, and 10.4% for J71:BTTIC-, PBDB-T:BTTIC-, and PTB7-Th:BTTIC-based PSCs, respectively, significantly higher than the PCEs of the fullerene-or other non-fullerene-based counterparts. Moreover, another famous p-type polymer donor PffBT4T-2OD, which shows poor solubility in chloroform and has not yet been studied in non-fullerene PSCs, is also investigated. Processing by dissolving PffBT4T-2OD and BTTIC in boiling chloroform enables PffBT4T-2OD:BTTIC-based PSCs with a PCE of 10.18%, which is significantly higher than that of PSCs (4.78%) before using boiling chloroform processing. The good compatibility of BTTIC with polymers that have either large, moderate, or small bandgaps makes it a promising nonfullerene acceptor for next-generation non-fullerene PSCs.

Asymmetric Acceptors with Fluorine and Chlorine Substitution for Organic Solar Cells toward 16.83% Efficiency

“…The development of organic solar cells (OSCs) has experienced a prosperous period in the past decade. [ 1–33 ] Due to their noticeable properties such as semi‐transparency, flexibility and environmental friendliness, the passion of commercialization from researchers and investors is always high. [ 34–38 ] At present, focusing on designing well performed “acceptor‐donor‐acceptor (A‐D‐A)”‐type small molecular acceptors (SMAs), especially the A‐DA'D‐A structured SMAs, is the mainstream of breaking through the bottleneck of power conversion efficiencies (PCEs), for their photovoltaic properties can be easily tuned by simple synthesis steps.…”

Unconjugated Side‐Chain Engineering Enables Small Molecular Acceptors for Highly Efficient Non‐Fullerene Organic Solar Cells: Insights into the Fine‐Tuning of Acceptor Properties and Micromorphology

“…Currently, the prevailing type of small molecule acceptor (SMA) is based on the A‐D‐A structure, that is, an electron‐rich core flanked with two electron‐deficient groups . To further boost the power conversion efficiency (PCE) of a non‐fullerene OSC device, which is proportional to the product of the open‐circuit voltage ( V OC ), the short‐circuit current ( J SC ), and the fill factor (FF), deep insights into the structure–property–performance relationship are needed, particularly for the emerging families of non‐fullerene moieties that have shown great potential in achieving high‐performance OSCs . Some significant achievements have been made to this end.…”

Chalcogen‐Fused Perylene Diimides‐Based Nonfullerene Acceptors for High‐Performance Organic Solar Cells: Insight into the Effect of O, S, and Se

“…Recently, A–D–A‐type NFAs have endowed organic solar cells (OSCs) with power conversion efficiencies (PCEs) exceeding 16%, which superseded the previously leading place of FAs and inaugurated a new era of OSC research . Apart from the A–D–A‐type NFAs, perylene diimide (PDI) units have also come into wide use for constructing n‐type organic semiconductors .…”