Power conversion efficiency and long-term stability are two critical metrics for evaluating the commercial potential of organic photovoltaics. Although the field has witnessed a rapid progress of efficiency towards 19%, the intrinsic trade-off between efficiency and stability is still a challenging issue for bulk-heterojunction cells due to the very delicate crystallization dynamics of organic species. Herein, we developed a class of non-fullerene acceptors with varied side groups as an alternative to aliphatic chains. Among them, the acceptors with conjugated side groups show larger side-group torsion and more twisted backbone, however, they can deliver an efficiency as high as 18.3% in xylene-processed cells, which is among the highest values reported for non-halogenated solvent processed cells. Meanwhile, decent thermal/photo stability is realized for these acceptors containing conjugated side groups. Through the investigation of the geometry–performance–stability relationship, we highlight the importance of side-group steric hinderance of acceptors in achieving combined high-performance, stable, and eco-friendly organic photovoltaics.

Exaggerated charge losses from excited to charge transfer (CT) and ground states in bulk heterojunction (BHJ) structures results in small voltages (< 1 V) for organic solar cells (OSCs). Characterizing morphology‐voltage loss correlations is difficult due to the complexity of BHJ structures but promises the realization of 20% efficiency for OSCs. By utilizing two similar non‐fullerene acceptors (NFA) in a ternary blend, a pseudo‐binary system is constructed to control the acceptor composition and donor‐acceptor (D‐A) miscibility. Within the framework of miscibility‐morphology controlled device photovoltaics, it is found that higher D‐A miscibility results in enhanced domain purity, which is associated with inefficient excitons dissociation and improves the excited and CT state emission, thereby resulting in enhanced electroluminescence efficiency to reduce the non‐radiative (NR) loss contribution to device voltage. The simple but effective composition mediated morphology control identifies domain purity as one key feature to lower the NR recombination in high quantum yield polymer/NFA blends.

The demand for monitoring chemical and physical information surrounding, air quality, and disease diagnosis has propelled the development of devices for gas sensing that are capable of translating external stimuli into detectable signals. Metal−organic frameworks (MOFs), possessing particular physiochemical properties with designability in topology, specific surface area, pore size and/or geometry, potential functionalization, and host−guest interactions, reveal excellent development promises for manufacturing a variety of MOF-coated sensing devices for multitudinous applications including gas sensing. The past years have witnessed tremendous progress on the preparation of MOF-coated gas sensors with superior sensing performance, especially high sensitivity and selectivity. Although limited reviews have summarized different transduction mechanisms and applications of MOF-coated sensors, reviews summarizing the latest progress of MOF-coated devices under different working principles would be a good complement. Herein, we summarize the latest advances of several classes of MOF-based devices for gas sensing, i.e., chemiresistive sensors, capacitors, field-effect transistors (FETs) or Kelvin probes (KPs), electrochemical, and quartz crystal microbalance (QCM)-based sensors. The surface chemistry and structural characteristics were carefully associated with the sensing behaviors of relevant MOF-coated sensors. Finally, challenges and future prospects for long-term development and potentially practical application of MOF-coated sensing devices are pointed out.