A large-bandgap donor BTBR-2F based on noncovalent conformational lock has been designed and synthesized to achieve more complementary absorption with the PM6: Y6 blend in the near-ultraviolet region. The ternary...

An asymmetric small molecule donor TTBT-R, incorporated with 4,5-di(2-ethylhexyl)oxybenzo[2,1-b:3,4-b']dithiophene as the core, was exploited for high-performance ternary organic solar cells (OSCs), which possesses complementary absorption band and cascaded energy levels...

Non-conjugated electrolytes, PMDETA-DBO and PEDETA-DBO, are developed through the quaternization of diethylenetriamine derivatives with 1,8-dibromooctane, which can interestingly be deployed as low-cost, thickness-insensitive and low-temperature processable electron transporting layers (ETLs)...

Two terpolymers, TP-H and TP-EH, have been designed and synthesized by incorporating hexyl- or 2-ethylhexyl-substituted 3,6-bis­(4-alkylthiophen-2-yl)-1,2,4,5-tetrazine derivatives as the second electron-withdrawing moieties with a 20% molar ratio into the backbone of PM6, respectively. The introduction of s-tetrazine units can efficiently depress the highest occupied molecular orbital energy levels of the terpolymers, which results in higher open-circuit voltages (V oc’s) in the polymer solar cells (PSCs) than the PM6:Y6 PSCs. TP-H with hexyl side chains possesses a stronger molecular aggregation than TP-EH with 2-ethylhexyl side chains, and the former also shows better morphology with a nanofibrous network structure than the latter in blends with the acceptor Y6, which are all favorable for charge transport and exciton dissociation. As a result, the PSC based on the TP-H:Y6 blend achieves a higher efficiency of 16.76% with a short-circuit current density of 26.78 mA cm–2, a V oc of 0.851 V, and a fill factor of 73.53%. This work provides not only an s-tetrazine-based terpolymer for high-performance PSCs but also a helpful structure–property relationship about side-chain engineering toward the design strategy of terpolymers.

Two polymerized naphthalimide derivatives, named as N-TBHOB and N-DBH, are prepared by quaternization. They exhibit excellent performance as electron-transport layers (ETLs) in inverted organic solar cells (i-OSCs). The results indicate N-TBHOB with a reticulated structure owns a superior performance on electron extraction, electron transport, thickness tolerance, and less carrier recombination compared with N-DBH with linear structure. The i-OSCs based on N-TBHOB with PTB7-Th:PC 71 BM as the active layer achieve power conversion efficiencies (PCEs) of 10.72% and 10.03% under the thickness of 11 and 48 nm respectively, which indicates N-TBHOB possesses better thickness tolerance than most of organic ETLs in i-OSCs. N-TBHOB also shows more competent performance than N-DBH and ZnO in nonfullerene i-OSCs for comprehensively improved J sc , V oc , and fill factor (FF) values. Its i-OSC with PM6:Y6 blend presents a high PCE of 16.78%. The study provides an efficient strategy to prepare ETLs by combining conjugated and nonconjugated units with a reticulated structure in the backbone for high-performance i-OSCs.