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N‐type organic semiconductors are essential for the advancement of organic electronic devices. However, in relation to extensive research on n‐type and p‐type polymers, studies on high‐mobility n‐type small‐molecule semiconductors (SMSCs) are limited. Here, a series of ultra‐narrow bandgap n‐type SMSCs are developed on an A‐D‐A‐type structure. These SMSCs feature an exceptionally large π‐conjugated area, leading to strong intramolecular charge transfer and robust π‐π interactions. For the first time, central core and terminal halogenation are employed to control molecular surface electrostatic potential distribution, thereby regulating the π‐π stacking area (Sπ‐π) and studying their correlation. The research reveals that, in n‐type SMSCs with an edge‐on arrangement, introducing fluorine into the 2D central core can reduce the Sπ‐π, which is detrimental to the electron mobility (µe) of organic field‐effect transistors (OFETs). Conversely, terminal chlorination facilitates electron injection and improves µe. Consequently, DTPC‐OD‐4Cl, featuring shorter alkyl side chains and a non‐fluorinated 2D central core and undergoing terminal chlorination, achieved the highest µe of up to 0.52 cm2 V−1 s−1, ranking among the highest values reported for A‐D‐A type SMSCs. This work not only systematically investigated the influence of molecular structure on mobility but also provided novel insights for designing more efficient n‐type SMSCs. [ABSTRACT FROM AUTHOR]

Benefiting from their simple and cost‐effective fabrication procedures, printable mesoscopic perovskite solar cells (p‐MPSCs) exhibit substantial potential for large‐scale production. In p‐MPSCs, the thickness of the perovskite filled in the TiO2 and ZrO2 mesoporous layers is ≈3 µm. Therefore, the perovskite crystallization process is more intricate and challenging in the mesoporous structure than the general planar thin film (0.3–0.5 µm). In this work, a multifunctional fluorinated molecule is applied to work as an additive to improve the perovskite crystallization, enhance the device efficiency, and elevate the operational stability. This additive forms robust coordination between its carbonyl groups and uncoordinated Pb2+, thereby effectively passivating defects. The hydrophobic properties of the fluorinated molecule contribute to the device's water‐resistant capability and long‐term operational stability. With these synergistic effects, the power conversion efficiency (PCE) of small‐area cells (0.1 cm2) reaches 20.15% under 1 sun illumination. Large‐area modules (56.4 cm2) are fabricated and exhibit a PCE of 15.41%. [ABSTRACT FROM AUTHOR]

The commercial viability of all‐small‐molecule (ASM) organic solar cells (OSCs) requires high efficiency, long‐term stability, and low‐cost production. However, satisfying all these factors at the same time remains highly challenging. Herein, a volatile solid additive, namely, 1,8‐dichloronaphthalene (DCN) is demonstrated to simultaneously enhance the power conversion efficiency (PCE) and the storage, thermal as well as photo stabilities of oligothiophene ASM‐OSCs with concise and low‐cost syntheses. The improved PCEs are mainly due to the DCN‐induced morphology control with improved exciton dissociation and reduced non‐geminate recombination. Notably, the PCE of 16.0% stands as the best value for oligothiophene ASM‐OSCs and is among the top values for all types of binary ASM‐OSCs. In addition, devices incorporating DCN have shown remarkable long‐term stability, retaining over 90% of their initial PCE after dark storage aging of 3000 h and thermal or light stressing of 500 h. The findings demonstrate that the volatile‐solid‐additive strategy can be a simple yet effective method of delivering highly efficient and stable oligothiophene ASM‐OSCs with excellent commercial viability. [ABSTRACT FROM AUTHOR]

Fibrous interpenetrating network structure morphology is extremely crucial for all‐small‐molecule organic solar cells (ASM‐OSCs) in achieving high power conversion efficiency (PCE). Rational molecular design and suitable posttreatment to the film are feasible methods to accomplish this goal. Herein, two small molecule donors, namely T4 and T6, with different substituents on their selenophene conjugated units, alkyl for T4 while trialkylsilyl for T6, are developed. Both as cast devices obtain poor PCEs (≈4.5%) when blending these two donors with N3 due to the oversize phase separation. Satisfactorily, the PCEs are dramatically increased after CS2 annealing, which mainly originates from the favorable reorganization of donor and acceptor in the active layer, ultimately improving the phase separation and vertical electronic properties. As a result, the device based on trialkylsilyl‐substituted T6 acquires a remarkable PCE of 16.03%, much higher than that of the blends of alkyl‐substituted T4 and N3 (12.61%). The enhanced PCE of the T6‐based device is attributed to the deeper HOMO energy levels, more obvious fibrous interpenetrating networks, and stronger molecular interaction between T6 and N3, as compared with T4‐based ones. This study indicates that precise molecular design and the proper posttreatment process can be a brilliant approach for realizing highly efficient ASM‐OSCs. [ABSTRACT FROM AUTHOR]

Low cost, high efficiency, and high stability are the three key issues of organic solar cells (OSCs) that should be carefully considered to meet the requirement of future commercial applications. Therefore, the development of high‐performance organic photovoltaic materials with low synthetic cost has been becoming a crucial challenge in the field of OSCs. Herein, two new low‐cost small‐molecule donors (SM‐BF1 and SM‐BF2) are designed and synthesized with a facile synthetic route by replacing 4‐bromo‐2‐fluorobenzenethiol and 4‐bromo‐3‐fluorobenzenethiol with low‐cost 4‐bromo‐2‐fluoro‐1‐iodobenzene and 4‐bromo‐3‐fluoro‐1‐iodobenzene as key raw materials. Besides, the influence of the chemical steric effect of the phenyl conjugated side chains of the benzodithiophene (BDT) unit on photophysical properties, charge transfer, and photovoltaic properties are deeply investigated by the modulation of fluorine atom substituted position. As a result, SM‐BF1 with ortho‐fluorinated substituent has outstanding crystallization properties and better miscibility with acceptor Y6 and exhibits more desirable morphology and more balanced charge‐carrier transport properties, leading to a superior power conversion efficiency (PCE) to 15.71%. More encouragingly, according to the figure of merit (FOM) and the industrial figure of merit (i‐FOM) to evaluate the small‐molecule donors, the SM‐BF1‐based device has excellent potential for future commercial applications. [ABSTRACT FROM AUTHOR]

Large energy loss is one of the main limiting factors for power conversion efficiencies (PCEs) of organic solar cells (OSCs). To this effect, the chemical modifications of the famous Y‐series nonfullerene acceptor (NFA) BTP‐4Cl‐BO with a new end group, TPC‐Cl, whose π‐conjugation is extended through the fusing of 3‐(dicyanomethylene)indanone (IC) group with a chlorinated thiophene ring, to synthesize two novel NFAs, BTP‐T‐2Cl and BTP‐T‐3Cl are performed. For BTP‐T‐2Cl with two TPC‐Cl groups, the resulting OSC exhibits a modest PCE of 14.89% but an extraordinary low energy loss of 0.49 eV, because its superior electroluminescence quantum efficiency of 0.0606% mitigates significantly the nonradiative loss (0.191 eV). For BTP‐T‐3Cl with one TPC‐Cl group, the corresponding device shows a higher PCE of 17.61% accompanied by a slightly bigger energy loss of 0.51 eV, which can be ascribed to the optimized morphology and/or efficient charge generation. Furthermore, the ternary OSC adopting two NFAs of BTP‐T‐3Cl and BTP‐4Cl‐BO achieves an impressive PCE of 18.21% (certified value of 17.9%), which is among the highest values for OSCs to date. The above results demonstrate that expanding end groups of NFAs with electron‐donating rings is an effective strategy to realize lower energy losses for OSCs. [ABSTRACT FROM AUTHOR]

High‐performance organic solar cells (OSCs) at the current stage are majorly accomplished from the processing of halogenated solvents, such as chloroform, which will be constrained for upscale fabrication due to the adverse health and environmental impacts. Therefore, exploring the high‐performance OSCs from non‐halogenated solvent processing becomes highly necessary, yet largely lagged behind. Herein, it is demonstrated high‐performance OSCs can be obtained from the hot spin processing of different non‐halogenated solvents, and achieve the highest reported efficiency of OSCs from non‐halogenated solvent processing so far. It is revealed that the phase evolution of ternary blends during solution‐to‐solid transition has a correlation to the substrate temperature. With the elevated substrate temperature of hot spin coating, the optimal blend films can be secured in different kinds of non‐halogenated solvents. As result, high‐performance OSCs are obtained with excellent power conversion efficiencies of 18.25% in o‐xylene, 18.20% in p‐xylene, and 18.12% in toluene, respectively. To the author's best knowledge, these results represent the best‐performed OSCs made from non‐halogenated solvents so far. [ABSTRACT FROM AUTHOR]

Herein, asymmetric isomer effects are systematically explored by designing and synthesizing two benzo[c][1,2,5]thiadiazole (BT)‐fused nonacyclic electron acceptors. By changing from BP6T‐4F to asymmetric ABP6T‐4F, significantly enhanced dielectric constant and inhibited excessive molecular aggregation and unfavorable edge‐on orientation could be achieved. The reduced exciton binding energy also facilitates a more efficient dissociation process in PM6:ABP6T‐4F compared to PM6:BP6T‐4F with the same energy offset. Moreover, the weaker crystallization behavior enables a significantly enhanced miscibility between PM6 and ABP6T‐4F than that between PM6 and BP6T‐4F, which leads to an optimized micromorphology with smooth surface, suitable domain size, and ordered π–π stacking. Organic solar cells (OSCs) based on PM6:ABP6T‐4F achieve a 15.8% power conversion efficiency (PCE), which is remarkably higher than that of PM6:BP6T‐4F‐based OSCs (6.4%). Furthermore, ternary devices are also fabricated considering good compatibility between ABP6T‐4F and CH1007 to deliver a PCE over 17%. This study reveals the effectiveness and great potential of asymmetric isomerization strategy in regulating molecular properties, which will provide guidance for the future design of non‐fullerene acceptors. [ABSTRACT FROM AUTHOR]

It is highly desirable for all‐inorganic perovskite solar cells (PVSCs) to have reduced nonideal interfacial charge recombination in order to improve the performance. Although the construction of a 2D capping layer on 3D perovskite is an effective way to suppress interfacial nonradiative recombination, it is difficult to apply it to all‐inorganic perovskites because of the resistance of Cs+ cesium ions in cation exchange reactions. To alleviate this problem, a simple approach using an ultra‐thin 2D perovskite to terminate CsPbI3 grain boundaries (GBs) without damaging the original 3D perovskite is developed. The 2D perovskite at the GBs not only enhances the charge‐carrier extraction and transport but also effectively suppresses nonradiative recombination. In addition, because the 2D perovskite can prevent the moisture and oxygen from penetrating into the GBs and at the same time suppress the ion migration, the 2D terminated CsPbI3 films exhibit significantly improved stability against humidity. Moreover, the devices without encapsulation can retain ≈81% of its initial power conversion efficiency (PCE) after being stored at 40 ± 5% relative humidity for 84 h. The 2D‐based champion device exhibits a high PCE of 18.82% with a high open‐circuit voltage of 1.16 V. [ABSTRACT FROM AUTHOR]

Ternary strategies have attracted extensive attention due to their potential in improving power conversion efficiencies (PCEs) of single‐junction polymer solar cells (PSCs). In this work, a novel wide bandgap polymer donor (Egopt ≈ 2.0 eV) named PBT(E)BTz with a deep highest occupied molecular orbital (HOMO) level (≈−5.73 eV) is designed and synthesized. PBT(E)BTz is first incorporated as the third component into the classic PBDB‐T‐SF:IT‐4F binary PSC system to fabricate efficient ternary PSCs. A higher PCE of 13.19% is achieved in the ternary PSCs with a 5% addition of PBT(E)BTz over binary PSCs (12.14%). Similarly, addition of PBT(E)BTz improves the PCE for PBDB‐T:IT‐M binary PSCs from 10.50% to 11.06%. The study shows that the improved PCE in ternary PSCs is mainly attributed to the suppressed charge carrier recombination and more balanced charge transport. The generality of PBT(E)BTz as a third component is further evidenced in another efficient binary PSC system—PBDB‐TF:BTP‐4Cl: an optimized PCE of 16.26% is realized in the ternary devices. This work shows that PBT(E)BTz possessing a deep HOMO level as an additional component is an effective ternary PSC construction strategy toward enhancing device performance. Furthermore, the ternary device with 5% PBT(E)BTz displays better thermal and light stability over binary devices. [ABSTRACT FROM AUTHOR]

In organic solar cells (OSCs), the short exciton lifetime poses a significant limitation to exciton diffusion and dissociation. Extending exciton lifetime and suppressing recombination are crucial strategies for improving the OSC performance. Herein, an effective approach is proposed by introducing the phosphorescent emitter, tris(2‐(4‐(tert‐butyl)phenyl)‐5‐fluoropyridine)Iridium(III), with long‐lived triplet exciton lifetime in OSCs. This research reveals that the steric structure of fac‐Ir(tBufppy)3 exhibits excellent compatibility with both the donor PM6 and acceptor BTP‐eC9, maintaining efficiencies of over 90% even with a 30% third component loading. Moreover, a 10% addition of fac‐Ir(tBufppy)3 mitigates excessive aggregation in the acceptor BTP‐eC9, optimizing the active layer morphology and improving the fill factor. Transient absorption spectroscopy and transient photoluminescence measurements demonstrate that the introduction of fac‐Ir(tBufppy)3 significantly extends exciton lifetimes and suppresses recombination, which increases the short‐circuit current (JSC). Ultimately, employing the non‐halogenated solvent o‐xylene for processing, an impressive power conversion efficiency (PCE) of 18.54% is achieved in devices based on PM6:10%fac‐Ir(tBufppy)3:BTP‐eC9, surpassing the efficiency of binary PM6:BTP‐eC9 devices (17.41%). This work provides a promising approach to further improve the PCEs in binary OSCs by introducing a phosphorescent iridium(III) complex as the third component. [ABSTRACT FROM AUTHOR]

Regulation of the crystallization of perovskite films and avoiding the oxidation of Sn2+ during the deposition process are very important for achieving Sn/Pb binary perovskite solar cells (PVSCs) with high power conversion efficiency (PCE) and producibility. In this work, a high‐quality HC(NH2)2Pb0.7Sn0.3I3 (FAPb0.7Sn0.3I3) film deposited from the two‐step solution process by introducing methylammonium thiocyanate (MASCN) as a bifunctional additive into the precursor solution containing PbI2 and SnI2 is reported. MASCN can not only tune the morphology of the perovskite film but also stabilize the precursor solution via retarding the oxidation of Sn2+ through a strong coordination between SCN− and Sn2+. The Sn/Pb binary inverted PVSCs based on FAPb0.7Sn0.3I3 present a high fill factor of 0.79 and the best PCE of 16.26% in the case of 0.25 MASCN addition. The device fabrication producibility is also greatly improved due to the stabilized precursor solution with the aid of MASCN. The PCE of the device is almost independent of the storage time of the precursor solution within 124 d in the N2‐filled glove box. These results indicate that the precursor engineering with multifunctionality additive is an effective approach toward highly efficient and producible PVSCs for future commercialization. The advantage of methylammonium thiocyanate (MASCN) addition inside the two‐step deposition process in forming high quality FAPb0.7Sn0.3I3 films is demonstrated. MASCN can tune morphology of the perovskite film and retard the oxidation of Sn2+. The power conversion efficiency of the device reaches 16.26%, and is almost independent of the storage time of the precursor solution in the glove box within 124 d. [ABSTRACT FROM AUTHOR]