The energy loss in perovskite solar cells (PSCs) is a key factor that limits the full potential of photovoltaic performance to values below the Shockley–Queisser limit. Herein, we report a bilayer structure of the electron transport layer (ETL) for reducing energy loss in methylammonium lead triiodide (MAPbI₃)-based planar heterojunction PSCs. The controlled electronic structure of the bilayer ETL affords suitable energy band matching at the interface of the MAPbI₃ layer for electron transport/hole blocking, which effectively suppresses trap-assisted recombination at the interface of PSCs. As a result, the optimized bilayer ETL reduces charge recombination at the interfaces of the perovskite layer, boosting the power conversion efficiency (PCE) of the MAPbI₃-based PSCs up to 20.43% with an open circuit voltage (V_OC) as high as 1.20 V under 1 sun conditions. In addition, the bilayer ETL-based devices retained a high V_OC of 0.98 V under illumination from a white light emitting diode (1000 lux), realizing PCEs of up to 37.2% under indoor conditions with good ambient stability for >800 h. These findings suggest the importance and potential of the bilayer ETL for reduced energy loss to generate high power outputs in outdoor/indoor environments of PSCs.

Recent advancements in material design have facilitated the utilization of n-type conjugated molecules as solution-processed non-fullerene acceptors (NFAs), offering promising alternatives to conventional fullerene acceptors (FA) in organic solar cells (OSCs). This comprehensive review aims to shed light on the significant design concepts of perylene-diimide (PDI) chromophores, focusing on functionalized small molecule non-fullerene acceptors (SM-NFAs), which demonstrate high performance in OSCs. The PDI chromophore is systematically classified into mono, di, tri, and tetra PDI functionalized small molecule architectures, enabling a multidisciplinary exploration encompassing molecular structure, optical properties, electronic structure, and device performance within the scope of this review. Specifically, this review thoroughly discusses influential factors, such as rational design principles, diverse grafting sites for structural modifications, cutting-edge synthetic techniques, precise morphological control, and meticulous device optimization, all of which contribute to the advancement of PDI-based SM-NFAs in the next-generation materials category for OSCs. The proposed architectural configuration holds significant promise in facilitating roll-to-roll compatible OSCs that can achieve enhanced device performance. In the final chapter, we address chiral optics, organic photodetectors, sensors, and medical fluorescence imaging as PDI organic small molecules beyond OSCs to grasp the reader's knowledge. Furthermore, this review highlights the intricate interplay among the linear, bridged, and fused-ring types and the strategic linking positions of SM-NFA PDIs within high-performance NFAs, thereby elucidating their profound impact on photovoltaic properties based on more than 300 PDI derivatives. By effectively demonstrating the superior service performance and stability of PDIs-NFAs compared to conventional FA-based OSCs, this review substantiates the expectation that the forthcoming generation of PDIs-NFAs will exhibit notably improved optoelectronic performance.

The methoxy-type silane coupling agents were synthesized via the modification of the hydrolyzable group and characterized to investigate the change in properties of silica/rubber composites based on the different silane coupling agent structures and the masterbatch fabrication methods. The prepared methoxy-type silane coupling agents exhibited higher reactivity towards hydrolysis compared to the conventional ethoxy-type one which led to the superior silanization to the silica filler surface modified for the reinforcement of styrene-butadiene rubber. The silica/rubber composites based on these methoxy-type silane coupling agents had the characteristics of more developed vulcanization and mechanical properties when fabricated as masterbatch products for tread materials of automobile tire surfaces. In particular, the dimethoxy-type silane coupling agent showed more enhanced rubber composite properties than the trimethoxy-type one, and the environmentally friendly wet masterbatch fabrication process was successfully optimized. The reactivity of the synthesized silane coupling agents toward hydrolysis was investigated by FITR spectroscopic analysis, and the mechanical properties of the prepared silica-reinforced rubber polymers were characterized using a moving die rheometer and a universal testing machine.