A large-area module (active area > 20 cm 2 ) with a power conversion efficiency (PCE) of 10.4% (certified at 10.1%) using a non-fullerene blend was demonstrated, which is by far the highest PCE reported to date. The same module also delivers a power of 40 mW/cm 2 (PCE 22%) under indoor lighting. Equally important, PCEs of 12%-14% were achieved for blends processed in ambient and/or without halogenated solvent.

A simple method is demonstrated to improve the fi lm-forming properties and air stability of a conjugated polyelectrolyte (CPE) without complicated synthesis of new chemical structures. An anionic surfactant, sodium dodecybenzenesulfonate (SDS), is mixed with cationic CPEs. The electrostatic attraction between these two oppositely-charged materials provides the driving force to form a stable CPE-surfactant complex. Compared with a pure CPE, this electrostatic complex is not only compatible with highly hydrophobic bulk-heterojunction (BHJ) fi lms, e.g. poly(3-hexylthiophene):[6,6]-phenyl C 61 butyric acid methyl ester (P3HT:PCBM), but also works well with other low bandgap polymer-based BHJ fi lms. Using this complex as a cathode interface layer, a high power conversion effi ciency of 4% can be obtained in P3HT:PCBM solar cells together with improved stability in air. Moreover, ∼ 20% performance enhancement can also be achieved when the complex is used as an interlayer to replace calcium metal for low bandgap polymer-based BHJ systems.

Non-fullerene organic photovoltaics (OPVs) have displayed the highest power conversion efficiencies (PCEs) among OPVs. Herein, we describe a two-donor (PM6, TPD-3F)/one-acceptor (Y6) ternary blend having an optimized blend morphology that leads to improved OPV performance. Because TPD-3F has a HOMO energy level deeper than that of PM6, the value of V OC of the corresponding ternary device increased. Good miscibility between PM6 and TPD-3F, in conjunction with device optimization through the use of 1-chloronaphthalene as an additive, provided an optimized ternary blend morphology for efficient exciton dissociation and carrier transport and, therefore, larger PCE. Compared with the preoptimized PM6:Y6 binary device, the ternary device functioned with improvements in its short-circuit current density, value of V OC , and fill factor. As a result, the device PCE improved from 15.5 ± 0.19 to 16.6 ± 0.25% under AM 1.5G (100 mW cm −2 ) irradiation. The champion cell exhibited a PCE of 17.0%a value that is one of the highest for a ternary OPV. Furthermore, such devices exhibited outstanding shelf lifetimes, with long-term stability in air (25 °C, 40% humidity) without encapsulation; the performance remained high (at 15.4%) after storage for 820 h.

Benzo[d][2,1,3]thiadiazole (BT) is a markedly electron-deficient heterocycle widely employed in the realization of organic semiconductors for applications spanning transistors, solar cells, photodetectors, and thermoelectrics. In this contribution, we implement the corresponding isomer, benzo [d][1,2,3]thiadiazole (isoBT), along with new 6-fluoro-isoBT and 5,6-difluoro-isoBT units as synthons for constructing alternating copolymers with tetrathiophene (P1−P3). New isoBT-based small molecules as well as the corresponding BTquaterthiophene based polymers (P4−P6) are synthesized and characterized to probe architectural, electronic structural, and device performance differences between the two families. The results demonstrate that isoBT complements BT in enabling highperformance optoelectronic semiconductors with P3 exhibiting hole mobilities surpassing 0.7 cm 2 /(V s) in field-effect transistors and power conversion efficiencies of 9% in bulk-heterojunction solar cells.