Ternary organic solar cells are promising alternatives to the binary counterpart due to their potential in achieving high performance. Although a growing number of ternary organic solar cells are ...recently reported, less effort is devoted to morphology control. Here, ternary organic solar cells are fabricated using a wide‐bandgap polymer PBT1‐C as the donor, a crystalline fused‐ring electron acceptor ITIC‐2Cl, and an amorphous fullerene derivative indene‐C60 bisadduct (ICBA) as the acceptor. It is found that ICBA can disturb π–π interactions of the crystalline ITIC‐2Cl molecules in ternary blends and then help to form more uniform morphology. As a result, incorporation of 20% ICBA in the PBT1‐C:ITIC‐2Cl blend enables efficient charge dissociation, negligible bimolecular recombination, and balanced charge carrier mobilities. An impressive power conversion efficiency (PCE) of 13.4%, with a high fill factor (FF) of 76.8%, is eventually achieved, which represents one of the highest PCEs reported so far for organic solar cells. The results manifest that the adoption of amorphous fullerene acceptor is an effective approach to optimizing the ternary blend morphology and thereby increases the solar cell performance.
Ternary organic solar cells based on a wide‐bandgap polymer donor (PBT1‐C), a fullerene derivative indene‐C60 bisadduct (ICBA), and a crystalline fused‐ring electron acceptor (ITIC‐2Cl) yield an impressive efficiency of 13.4%, and a high fill factor of 76.8%, indicating that the use of an amorphous fullerene acceptor is an effective way to optimize the ternary blend morphology.
The blossoming of organic solar cells (OSCs) has triggered enormous commercial applications, due to their high‐efficiency, light weight, and flexibility. However, the lab‐to‐manufacturing translation ...of the praisable performance from lab‐scale devices to industrial‐scale modules is still the Achilles' heel of OSCs. In fact, it is urgent to explore the mechanism of morphological evolution in the bulk heterojunction (BHJ) with different coating/printing methods. Here, a general approach to upscale flexible organic photovoltaics to module scale without obvious efficiency loss is demonstrated. The shear impulse during the coating/printing process is first applied to control the morphology evolution of the BHJ layer for both fullerene and nonfullerene acceptor systems. A quantitative transformation factor of shear impulse between slot‐die printing and spin‐coating is detected. Compelling results of morphological evolution, molecular stacking, and coarse‐grained molecular simulation verify the validity of the impulse translation. Accordingly, the efficiency of flexible devices via slot‐die printing achieves 9.10% for PTB7‐Th:PC71BM and 9.77% for PBDB‐T:ITIC based on 1.04 cm2 . Furthermore, 15 cm2 flexible modules with effective efficiency up to 7.58% (PTB7‐Th:PC71BM) and 8.90% (PBDB‐T:ITIC) are demonstrated with satisfying mechanical flexibility and operating stability. More importantly, this work outlines the shear impulse translation for organic printing electronics.
A general approach for lab‐to‐manufacturing translation is developed to achieve high‐performance flexible organic solar modules without obvious efficiency loss. The shear impulse during the coating/printing process is applied to control the morphology evolution of the bulk heterojunction layer for both fullerene and nonfullerene acceptor systems. A quantitative transformation factor of shear impulse between slot‐die printing and spin‐coating is detected.
Semitransparent organic solar cells (STOSCs) are ideal candidates for building‐integrated photovoltaics. Power conversion efficiency (PCE) is one of the most important parameters of STOSCs, which is ...typically limited by the intrinsic narrow absorption of thin active layer. Ternary structure is demonstrated as an efficient approach to broaden the light absorption and manipulate the morphology, thus leading to improved PCEs by introducing a third component into the binary system. However, STOSCs based on ternary systems are rarely studied. In this contribution, semitransparent ternary solar cells are fabricated using a wide‐bandgap (E
g = 2.10 eV) polymer donor, PBT1‐S, as the third component. It is found that the addition of a small amount of PBT1‐S to PTB7‐Th:PC71BM blend has a negligible influence on its average visible transmittance (AVT) and color perception. A PCE of 9.2% is achieved for the champion ternary device with 20% AVT, which is one of the highest values for STOSCs. The results indicate that ternary structure is a promising approach for the fabrication of high‐performance STOSCs.
Semitransparent organic solar cells (STOSCs) based on ternary structure are rarely studied. Here, a high efficiency of 9.2% is achieved for the champion semitransparent ternary device with 20% average visible transmittance, which is among the highest power conversion efficiencies reported for STOSCs so far. This indicates that the ternary structure is a promising strategy to fabricate high‐performance STOSCs.
The fluorobenzotriazole (FTAZ)‐based copolymer donors are promising candidates for nonfullerene polymer solar cells (PSCs), but suffer from relatively low photovoltaic performance due to their ...unsuitable energy levels and unfavorable morphology. Herein, three polymer donors, L24, L68, and L810, based on a chlorinated‐thienyl benzodithiophene (BDT‐2Cl) unit and FTAZ with different branched alkyl side chain, are synthesized. Incorporation of a chlorine (Cl) atom into the BDT unit is found to distinctly optimize the molecular planarity, energy levels, and improve the polymerization activity. Impressively, subtle side chain length of FTAZ realizes a dramatic improvement in all the device parameters, as revealed by the short‐current density (Jsc) improved from 7.41 to 20.76 mA cm−2, fill‐factor from 36.3 to 73.5%, and even the open‐circuit voltage (Voc) from 0.495 to 0.790 V. The best power conversion efficiency (PCE) of 12.1% is obtained from the L810‐based device, which is one of the highest values reported for FTAZ‐based PSCs so far. Notably, the corresponding external quantum efficiency curve keeps a very prominent value up to 80% from 500 to 800 nm. The notable performance is discovered from the reduced energy loss, improved molecular face‐on orientation, the down‐shifted energy levels, and optimized absorption coefficient regulated by side‐chain engineering.
Three polymers L24, L68, and L810 are developed as donor materials for organic solar cells. As the alkyl side chain of the fluorobenzotriazole (FTAZ) unit increases, the L810‐based device exhibits lower energy loss, better molecular face‐on orientation, and a higher absorption coefficient. Consequently, the power conversion efficiency is improved to 12.1%, which is one of the highest values for FTAZ‐based devices.
The halogen‐free solvent additive, 1,4‐butanedithiol (BT) has been incorporated into PTB7‐Th:PC71BM, leading to higher power conversion efficiency (PCE) value as well as substantially enhanced ...thermal stability, as compared with the traditional 1,8‐diiodooctane (DIO) additive. More importantly, the improved thermal stability after processing with BT contributes to a higher glass transition temperature (Tg) of PTB7‐Th, as determined by dynamic mechanical analysis. After thermal annealing at 130 °C in nitrogen atmosphere for 30 min, the PCE of the specimen processed with BT reduces from 9.3% to 7.1%, approaching to 80% of its original value. In contrast, the PCE of specimens processed with DIO seriously depresses from 8.3% to 3.8%. These findings demonstrate that smart utilization of low‐boiling‐point solvent additive is an effective and practical strategy to overcome thermal instability of organic solar cells via enhancing the Tg of donor polymer.
The halogen‐free solvent additive of 1,4‐butanedithiols (BT) can improve power conversion efficiency and substantially enhance thermal stability of PTB7‐Th:PC71BM, as compared with the traditional 1,8‐diiodooctane additive. More importantly, the improved thermal stability after processing with BT contributes to higher glass transition temperature (Tg) of PTB7‐Th, as determined by dynamic mechanical analysis.
Morphological stability is crucially important for the long‐term stability of polymer solar cells (PSCs). Many high‐efficiency PSCs suffer from metastable morphology, resulting in severe device ...degradation. Here, a series of copolymers is developed by manipulating the content of chlorinated benzodithiophene‐4,8‐dione (T1‐Cl) via a random copolymerization approach. It is found that all the copolymers can self‐assemble into a fibril nanostructure in films. By altering the T1‐Cl content, the polymer crystallinity and fibril width can be effectively controlled. When blended with several nonfullerene acceptors, such as TTPTT‐4F, O‐INIC3, EH‐INIC3, and Y6, the optimized fibril interpenetrating morphology can not only favor charge transport, but also inhibit the unfavorable molecular diffusion and aggregation in active layers, leading to excellent morphological stability. The work demonstrates the importance of optimization of fibril network morphology in realizing high‐efficiency and ambient‐stable PSCs, and also provides new insights into the effect of chemical structure on the fibril network morphology and photovoltaic performance of PSCs.
A series of copolymers via a random copolymerization approach are designed and synthesized. The well‐defined fibril interpenetrating morphology with appropriate phase separation in PT2‐based blends can efficiently suppress the unfavorable aggregation, resulting in excellent morphological stability and high efficiency. The work demonstrates the importance of optimization of fibril network morphology in realizing high‐efficiency and ambient‐stable polymer solar cells.
Supercapacitors can harvest electrical energy from intermittent sources and transfer it quickly, but their specific energy must be raised if they are applied to efficiently power wearable and ...flexible electronics, as well as larger equipment. However, the remaining big gap between the lab research and practical applications seriously hinders the further progress of advanced supercapacitors, especially for electrode materials. Consequently, from a commercial/usable perspective, a clear guideline from lab research to commercialization is highly desired for bringing advanced supercapacitors from basic research into reality. This review focuses on the key factors of advanced supercapacitors from lab research to commercialization and summarizes recent progress in the field of supercapacitors as well as outlines key perspectives for future research. First, the several energy storage mechanisms are illustrated for building better supercapacitors. Then, the up‐to‐date key achievements and progresses of smart methods toward high‐energy supercapacitors and effective strategies for commercial‐level mass‐loading as well as high packing density electrodes are summarized and commented upon. Also, integrated systems of supercapacitors and application fields of commercial supercapacitors are also highlighted. Subsequently, future research directions are presented here to guide research toward the commercialization of advanced supercapacitors.
The remaining big gap between the lab research and practical applications seriously hinders the further progress of advanced supercapacitors, especially for electrode materials. This review focuses on providing readers a clear guideline and comprehensive insights for bringing advanced supercapacitors from basic research into reality. Moreover, several key scientific challenges and the perspectives about the commercialization of advanced supercapacitors are also discussed.
The exploitation of natural materials has received growing attention because of the needs of environmental sustainability. In contrast to petroleum‐based synthetic materials, natural materials ...possess significant advantages of abundant, low‐cost, degradable, and renewable. Here, the recent research status of natural materials as flexible substrate, cathode interfacial material, and anode interfacial material for organic photovoltaics (OPVs) are first presented. Then, the confronted key challenges that limit the widespread application of natural materials for OPVs is summarized, including complex multilength scaled aggregation morphology, non‐conjugated structure, and unclear working mechanism. Finally, their potential solutions from the perspective of chemical structure are proposed for constructing efficient OPVs. It is believed that natural materials have a broad landscape in low‐cost and green manufacturing technology for OPVs in the future.
Natural materials possess significant advantages of abundant, low‐cost, degradable, and renewable. Herein, recent advancements toward developing sustainable organic solar cells using natural materials as flexible substrate, cathode interfacial material, and anode interfacial material are reviewed.
Imitating from natural biology, shape-programmable materials play a significant role in biomimetic applications. Magneto-active soft materials (MASMs) with programmable shapes, which can assume ...desired shapes under external magnetic actuation as well as potential for applications in actuators, soft robotics, medical care, and bionics. Here, we propose a shape-programming strategy that can quickly design the desired magnetic moment and actuating magnetic fields for MASMs with fast, reversible, programmable, and stable shape transformation properties. This method allows us to program the magnetic moment in the soft matrix by printing diverse magnetic structural elements. The flexible matrix and soft-magnetic 3D printing filament enable the high-performance deformation of MASMs. With these capabilities, various biomimetic structures (inchworm, manta ray, and soft gripper) can be easily fabricated with walking, swimming and snatching functions. The proposed shape-programming strategy would provide an efficient way to fully capitalize the potential of MASMs, allowing researchers to develop a wide range of soft actuators that are critical in soft robotics, medical care, and bionics applications.
The rapid advancement in soft actuators imposes an emergent requirement for soft stimuli-sensitive materials that are deformable and stiffness variable and show designability and adaptivity. Soft ...actuators based on magneto-sensitive materials with outstanding magnetic-control performance are highly desirable in research. In this paper, we developed a versatile magnetorheological plastomer (MRP) based on polycaprolactone (PCL)/thermoplastic polyurethane (TPU) polymer blends. The MRP showed 3D printability, switchable mechanics, shape memory, and self-healing properties. The thermoplasticity of the matrix enables fused deposition modeling 3D printing, which affords the MRP excellent shape designability. By taking advantage of the phase transition and magnetorheological effect, the dramatic switchable mechanical properties of MRP can be triggered by thermal stimulus and magnetic field. The influences of matrix, particle content, temperature and magnetic field on the mechanical properties were discussed comprehensively, and possible physical mechanisms were proposed so that the result can be qualitatively explained. Based on hybrid crystalline and amorphous regions of PCL and TPU, the MRP exhibited superior shape memory and self-healing properties. This work may play an important role in the future development of multifunctional magneto-sensitive material and promote the application of soft actuators in the fields of soft robotics, medical care, and bionics applications.
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