Molecular aggregation and phase morphology of the active layer in bulk-heterojunction (BHJ) solar cells are crucial to attain efficient and stable organic solar cells (OSCs). Most studies of solid additives in high-efficiency OSCs have primarily focused on the impact of these additives on the acceptors, while largely neglecting the synergistic effects of additives on donor and acceptor. Herein, we introduce a synergistic morphology regulation approach by utilizing two isomeric solid additives (4-bromobenzothiadiazole (4-BBT) and 5-bromobenzothiadiazole (5-BBT)). 4-BBT or 5-BBT promotes both the crystallinity and π–π stacking of the polymer donor PM6 while effectively suppressing excessive aggregation of the acceptor L8-BO, which leads to a favorable phase morphology. When mixed additives are loaded simultaneously, synergistic regulation can be achieved, enabling finer nanoscale phase separation with enhanced donor–acceptor miscibility and well-ordered packing. Further analyses indicate that the mixed additives effectively slow down the film formation and charge relaxation dynamics, thereby prolonging crystallization time and enhancing π–π stacking while effectively suppressing recombination losses. Consequently, modified by the mixed additives, the PM6:L8-BO device demonstrates high efficiency of 19.32%, coupled with improved short-circuit current (J_SC) and fill factor (FF). Besides, the D18:L8-BO-C4-based devices treated with 4-BBT+5-BBT delivered a remarkable efficiency of 20.13%, with an outstanding FF of 83.01%. Furthermore, the optimized device shows excellent photostability and thermal stability. This study provides a versatile and effective strategy for accurate regulation of the molecular aggregation and phase morphology through synergistic isomeric solid additive engineering, thereby offering insights into the rational design of efficient and stable organic photovoltaic materials.

Small molecule donor/polymer acceptor (SMD/PA) solar cells demonstrate high stability and notable performance advantages due to reduced molecular weight distribution variability, indicating potential breakthroughs in power conversion efficiency (PCE). However, research in this area is limited. This manuscript synthesizes two novel small donor molecules, DTBDT-C1-D6 and DTBDT-C3-D6 (DTBDT represents dithieno[2,3-d:2’,3’-d’]benzo[1,2-b:4,5-b’]dithiophene, C3 denotes a three-carbon spacer between the alkyl chain’s branching point and the core linkage site, C1 denotes a one-carbon spacer between the alkyl chain’s branching point and the core linkage site, and D6 represent π bridge has two alkyl chains with six carbon atoms each), combined additives of chloronaphthalene (CN), to investigate their effects on packing properties, film formation dynamics, and device performance. Interestingly, the CN significantly impact the packing modes and ability of the donors, and ultimately the intermolecular interaction and the dynamics of film forming, making the device performance fluctuate wildly with the CN ratio. The DTBDT-C3-D6 molecule, with alkyl chains branching away from the donor core, with 1% CN in volume, forms an interpenetrating framework by the proper hetero/homo molecular interaction, promoting a PCE of 13.4%, significantly exceeding the 5.65% of the DTBDT-C1-D6 blend and also other CN volume ratios. This PCE is the highest reported for SMD/PA-type organic solar cells (OSCs). The findings highlight the importance of alkyl side chain branching and additives in modulating intermolecular interactions and film dynamics, offering insights into morphology control in OSCs.

In the past two decades, various research works have been conducted in the field of flexible electronic devices (FEDs). Researchers have focused their efforts on solving the existing challenges in the electronic, electrochemical, and mechanical behaviors of FEDs. The importance of flexible lithium-ion batteries (FLIBs) in the area of FEDs is evident; however, less attention has been paid to the mechanical behavior of FLIBs in comparison with the material and electrochemical characteristics. The present paper reviewed the research works in the FLIBs, focusing on their mechanical integrity and electrochemical performances. First, an introduction to FLIBs was presented, and the previous review papers published in this field were briefly introduced. Then, a detailed review of the available electrochemical and mechanical research works on FLIBs was presented. Moreover, the mechanical testing methods (tensile, compressive, indentation, fatigue, and adhesion) for the characterization of FLIBs’ components, the research works on the simulation and modeling of the mechanical behavior of FLIBs, and a summary of the present situation and the future trend of research in this field were reviewed and presented.

The slot-die coating is recognized as the most compatible method for the roll-to-roll (R2R) processing of large-area flexible organic solar cells (OSCs). However, the photovoltaic performance of the large-area flexible all-polymer solar cells was significantly lagging behind that of polymer donors with small molecule non-fullerene acceptors devices. In this work, the 1 cm² flexible device of an all-polymer system, PTQ10:PYF-T-o, fabricated by slot-die coating, achieves an excellent efficiency of 11.24% via controlling the coating temperatures. It is found that, compared with the donor, the crystallinity of PYF-T-o plays a crucial role in device performance. The all-polymer flexible devices show superior mechanical bending stability, maintaining an efficiency of over 95% of the initial value during a 1000-cycle bending test.

Halogenated thiophenes are generally used units for constructing organic semiconductor materials for photovoltaic applications. Here, we introduced thiophene, 2-bromothiophene, and 2-chlorothiophene units to the central core of quinoxaline-based acceptors and obtained three acceptors, Qx-H, Qx-Br, and Qx-Cl, respectively. Compared with Qx-H, Qx-Br and Qx-Cl showed enhanced absorption, down-shifted energy levels, improved crystallinity, and reduced energy disorder. The improved crystallinity significantly optimized the blend morphology, leading to efficient charge generation and transport and, therefore, less bimolecular recombination. Eventually, PM6:Qx-Br-based devices exhibited an outstanding power conversion efficiency of 17.42% with a high open-circuit voltage (V_OC) of 0.915 V. Furthermore, Y6 was introduced into the PM6:Qx-Br binary system to improve the light utilization, and the resulting ternary devices delivered a high PCE of 18.36%. This study demonstrated the great potential of halogenated thiophene substitution in quinoxaline-based acceptors for building high-performance organic solar cell acceptor materials.

Organic solar cells (OSCs) are emerging as a promising candidate for space applications due to their low cost, lightweight flexibility, and printable fabrication. Small-area single-junction OSCs have achieved power conversion efficiency (PCE) exceeding 19%, demonstrating a specific power significantly higher than traditional silicon-based and Ⅲ-Ⅴ-based photovoltaics. Their foldable design further reduces transportation volume, making them ideal for aerospace systems. However, large-area module fabrication still faces challenges such as efficiency loss, structural design limitations, and long-term operational stability. This study focuses on the key issues of flexible OSCs in space environments, systematically analyzing the optimization of solution-printing techniques for scalable production and summarizing the factors contributing to efficiency degradation during upscaling. Additionally, the stability of OSCs under simulated extreme conditions, including ultra-high vacuum, wide temperature ranges, and radiation exposure, is reviewed. Based on recent advances, the study proposes future directions, including molecular structure optimization, tandem device design, and process improvements, to push PCE beyond 20% and enhance long-term stability. These efforts aim to establish a theoretical and technical foundation for the application of flexible OSCs in spacecraft power systems.

Small-molecule organic solar cell is a category of clean energy potential device since charge transfers between donor and acceptor. The morphologies, co-assembly behavior, interaction sites, and charge transfer of BTID-nF (n = 1, 2)/PC₇₁BM donor–acceptor system in the active layer of organic solar cell have been studied employing scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), density functional theory (DFT) calculations, and transient absorption (TA) spectroscopy. The results show that BTID-1F and BTID-2F form bright strip structures, whereas BTID-nF (n = 1, 2)/PC₇₁BM form ridge-like structures with each complex composed of one BTID-nF (n = 1, 2) molecule and four PC₇₁BM molecules which adsorbed around the BTID-nF (n = 1, 2) molecule by S···π interaction. With the assistance of S···π interaction between BTID-nF (n = 1, 2) and PC₇₁BM, BTID-nF (n = 1, 2)/PC₇₁BM co-assembled ridge-like structures are more stable than the BTID-nF (n = 1, 2) ridge structures. To investigate the charge transfer of BTID-nF (n = 1, 2)/PC₇₁BM system, STS measurements, DFT calculation, and TA spectroscopy are further performed. The results show that charge transfer occurs in BTID-nF (n = 1, 2)/PC₇₁BM system with the electron transferring from BTID-nF (n = 1, 2) molecules to PC₇₁BM.

Conducting polymer actuators that can undergo complex and coordinated motions are generally obtained by using complex microfabrication methods to pattern several conducting polymer components. Herein, we describe a facile approach for fabricating electromagnetic synergetic actuators based on polypyrrole/Fe₃O₄ hybrid nanotube arrays. The actuator can perform biomimetic movements like arm-hand coordination. In this case, a magnetic field is used for primary actuation like an arm, i.e., large-scale angular movement, and an electric potential is used for secondary adjustment like a hand, i.e., small-scale angular movement.