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Organic photovoltaics (OPVs) have made significant strides with efficiencies now exceeding 20%, positioning them as potential competitors to inorganic solar technologies. One of the most critical challenges toward this goal is the severe open‐circuit voltage (Voc) loss caused by the nonradiative charge recombination (NRCR). Herein, this review comprehensively summarizes the NRCR mechanisms and suppression techniques of OPVs across various scales from molecule to device. Specifically, the origins of NRCR in a single molecule are first summarized, and molecular design principles toward high photoluminescence quantum yield are reviewed following the Marcus theory. Next, the effect of aggregation on NRCR is reviewed, as well as the molecular and processing strategies to modulate the film packing for NRCR suppression. Furthermore, the progresses in the avoidance of nonradiative loss pathways mediated by charge transfer states and triplet states in donor:acceptor bulk heterojunctions are tracked. Besides, the interfacial optimization and device structure design to maximize the electroluminescent quantum efficiency are presented. Finally, several potential pathways toward curtailing NRCR for high‐performance OPVs are outlined. Therefore, this review shows an insightful perspective to understand and mitigate the NRCR at multi‐scales, and is poised to provide a clear roadmap for the next breakthrough of OPVs. [ABSTRACT FROM AUTHOR]

High-level synthesis (HLS) is important for compiling an application design onto field-programmable gate array (FPGA) but still faces challenges of balancing scalability and quality of results in the scheduling process. In this article, we propose an entropy-directed scheduling (EDS) algorithm that efficiently generates high-quality schedules for FPGA HLS. This article is novel in three ways. First, we make the first attempt to adopt entropy in the scheduling of HLS, which is an intuitive and robust measurement with lots of good analytic properties. Second, we creatively leverage the maximum entropy principle to describe the scheduling process, which is proved equivalent to the optimal solution in some particular cases. Third, we make EDS automatically analyze the input graph structure and leverage a three-stage scheduling process to obtain high-quality results. As a result, EDS has the lowest time complexity among existing scheduling algorithms and is flexible to solve both latency- and resource-constrained problems while satisfying other constraints. The experimental results show that for latency-constrained scheduling problem, EDS reduces up to 68% resource usage and is 294 × faster than the force-directed scheduling algorithm. For resource-constrained scheduling problem, EDS obtains near-optimal solutions with an average speedup of 16 410 × compared with ILP. To our best knowledge, this is the first EDS algorithm for FPGA HLS. [ABSTRACT FROM AUTHOR]

Single crystal dielectrics are ideal candidates for high-performance organic field-effect transistors (OFETs) due to the ordered molecular packing and smooth surface. However, it doesn't obtain much attention due to the lack of facile preparation methods. Here, solution-grown smooth poly( ε -caprolactone) (PCL) single crystals with width in tens of microns are obtained and used as the dielectric for the OFETs. The interface between the semiconductor and the PCL single crystal dielectrics are more favorable to the charge carrier transport than spin-coated PCL thin-film dielectrics, exhibiting much higher charge mobility. With 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) single crystal as semiconductor layer, the average OFET mobility reaches up to 1.70 ± 0.97 cm 2 V −1 s −1 with the highest value of 4.95 cm 2 V −1 s −1 . This result demonstrated that structural ordering of the polymer dielectrics is critical to further advance the performance of OFET devices. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The halide perovskite semiconductors‐based solar cells (PVSCs) show great promise as next‐generation renewable energy sources, with the merits of low cost, high performance, good flexibility, etc. A major difference distinguishing the perovskite semiconductors from others lies in their ionic feature. This intrinsic property induces "freely‐moving" ions to migrate and accumulate in the perovskite films and devices under different external stresses. As a charge carrier, these processes will strongly couple with the electronic process, and dramatically affect the performance and stability of PVSCs. This review summarizes and discusses the recent progresses and fundamental understandings of ion migration and accumulation behaviors in PVSCs. First, the basic principles of the general ion migration are reviewed. Second, following the fundamental understandings, the critical factors, e.g., ion migration activation energy, ion density, ion diffusion coefficient, etc., are extracted to understand the ion migration and accumulation in perovskite film. Third, the principles governing ion accumulation behaviors under different external stresses are discussed. Finally, the effect of ion migration and accumulation on band bending, and device performance is presented. Therefore, we hope this review provides a tutorial and insightful perspective regarding the most prominent ionic feature of perovskite semiconductors and their application for photovoltaics. [ABSTRACT FROM AUTHOR]

Abstract: The gas-sensitivities of zinc phthalocyanine (ZnPc) and its fluorinated derivative (zinc hexadecafluorophthalocyanine—ZnF16Pc) films to a series of reducing gases at room temperature are studied. The results indicate that the gas-sensitivities and the response rates of ZnPc film to ammonia, trimethylamine and methylamine can be improved significantly via fluorination. In a concentration range of 0.5–1 ppm (3.66×10−8–7.13×10−7 mol/mL), the gas-sensitivities to ammonia, methylamine and trimethylamine can reach 2–4 orders, respectively. The ZnF16Pc film has a good selectivity and stability, and it can be completely recovered by high-purity N2 at room temperature. [Copyright &y& Elsevier]

Abstract: Colloidal nanoparticles consisting of oxidized carbon black (CB) coated by poly(vinyl pyrrolindone) (PVP) were fabricated by a simple phase separation method. The morphology of the CB/PVP composite nanoparticles demonstrated by transmission electron microscopy (TEM) indicated a core-shell structure for the composite. Crosslinking reaction was undertaken to tighten the contact between the PVP shell and the CB core, which made the nanocomposite much more stable in water. The particle size distribution for the nanoparticles was narrow with the mean diameter of 62nm. The effects of two principle parameters, which are the amount of nonsolvent for PVP and the crosslinking initiator, were also investigated. [Copyright &y& Elsevier]

Nanoscale azo pigment immobilized on the outer shell of multiwalled carbon nanotubes (MWCNT–AZO) were prepared by modified liquid phase reprecipitation method, and the MWCNT–AZO hybrid was characterized by means of TEM, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–VIS absorption. The photoconductivity of single-layered photoreceptors, where MWCNT–AZO served as the charge generation material (CGM), was studied by the xerographic photoinduced discharge method. The results indicated that the MWCNT–AZO nano hybrid showed broader and enhanced photosensitivity than MWCNT/bulk azo pigments (AZO) blend or the bulk AZO did, which was interpreted in terms of nanometer size effect of MWCNT–AZO hybrid and charge transfer from AZO nanoparticles to MWCNT. [Copyright &y& Elsevier]

Abstract This article reviews the recent development of organic electron transport materials applied in the fields of organic photoconductors, light-emitting diodes, field-effect transistors and solar cells. Several technologies for charge carrier mobility measurement are summarized and compared, and a series of basic principles for designing high-performance organic electron transport materials are suggested as well. [ABSTRACT FROM AUTHOR]

The ternary strategy proves effective for breakthroughs in organic photovoltaics (OPVs). Elevating three photovoltaic parameters synergistically, especially the proportion‐insensitive third component, is crucial for efficient ternary devices. This work introduces a molecular design strategy by comprehensively analyzing asymmetric end groups, side‐chain engineering, and halogenation to explore the outstanding optoelectronic properties of the proportion‐insensitive third component in efficient ternary systems. Three asymmetric non‐fullerene acceptors (BTP‐SA1, BTP‐SA2, and BTP‐SA3) are synthesized based on the Y6 framework and incorporated as the third component into the D18:Y6 binary system. BTP‐SA3, featuring asymmetric terminal (difluoro‐indone and dichloride‐cyanoindone terminal), with branched alkyl side chains, exhibited high open‐circuit voltage (VOC), balanced crystallinity and compatibility, achieving synergistic enhancements in VOC (0.862 V), short circuit‐current density (JSC, 27.52 mA cm−2), fill fact (FF, 81.01%), and power convert efficiency (PCE, 19.19%). Device based on D18/Y6:BTP‐SA3 (layer‐by‐layer processed) reached a high efficiency of 19.36%, demonstrating a high tolerance for BTP‐SA3 (10–50%). This work provides novel insights into optimizing OPVs performances in multi‐component systems and designing components with enhanced tolerance. [ABSTRACT FROM AUTHOR]

Although the layer‐by‐layer (LBL) processing can usually achieve an optimal bulk‐heterojunction morphology for high‐performance Organic photovoltaics (OPVs), the unambiguous working principles governing the morphology evolution are still lacking. To address this issue, here the phase‐separation kinetics of LBL processing are comprehensively studied using in situ spectroscopies, which are very sensitive to the intermolecular interactions, e.g. the molecular packing and D:A phase‐separation. Upon casting the nonfullerene acceptor (i.e., the BTP‐eC9) solution on top of the polymer donor, i.e., PM6, it is found that 1) the solvent will first swell the polymer and induce a polymer gel, 2) following the polymer gelation, the NFAs will immediately permeate into the cavities of polymer gel and form a molecular‐level D:A mixing, and 3) with the evaporation of the solvent, phase‐separation between the donor and acceptor occurs and results in a bulk‐heterojunction morphology as those achieved with blend‐cast processing. With these understandings, more diverse processing conditions have been purposely utilized to dictate the phase evolution process precisely. As a result, a high efficiency of 19.7% is reached, representing one of the best among binary OPVs. Therefore, this work deciphers phase‐separation kinetics of LBL processing and should pave the way toward advanced morphology control for high‐performance OPVs. [ABSTRACT FROM AUTHOR]

Although encouraging progress in spin‐coated small‐area organic solar cells (OSCs), reducing efficiency loss caused by differences in film uniformity and morphology when up‐scaled to large‐area modules through meniscus‐guided coating is an important but unsolved issue. In this work, in‐depth research is conducted on the influence of both liquid and solid additives on the film uniformity and morphology of active layer in blade‐coated PM6:L8‐BO binary system. The study reveals that high boiling point liquid additives like 1,8‐diiodooctane (DIO) used in blade‐coating not only delay the volatilization of the solvent but also trigger the Marangoni flow in the same direction as capillary flow, causing excessive aggregation of acceptors, therefore destroying device performance. On the contrary, the solid additive 2‐Iododiphenyl ether (IDPE), which is first reported in this work, can preserve the mechanism for improving device performance while effectively suppressing the excessive aggregation of acceptors during the film‐forming process in blade‐coating from halogen‐free solvent of toluene, resulting in highly homogeneous large‐area active layer films. Consequently, organic solar modules with an impressive efficiency of 15.34% with a total module area of 18.90 cm2 via blade‐coating based on PM6:L8‐BO are achieved. This study not only provides a deep understanding on the effect of liquid and solid additives during blade‐coating from the perspective of fluid mechanisms but also gives a pathway for the development of green solvent printed high‐efficiency OSCs. [ABSTRACT FROM AUTHOR]

Surface or interface engineering is one of the most effective strategies to improve the device performance and stability of perovskite solar cells (PSCs), owing to the fact that the defects are mainly located at the surface. Organosilanes are among the most promising surface modifiers due to their unique cross‐linking ability, which makes a robust layer to further protect the underneath perovskites. However, the influence of tail functional groups of organosilanes on the device performance and stability has never been systematically investigated. Herein, a series of organosilanes with different chain lengths, fluorination, and different interactions toward perovskite are applied to modify the perovskite. Tail functional groups that show passivation ability toward perovskite are demonstrated to effectively reduce trap densities and thus improve the power conversion efficiencies (PCEs), while the fluorinated functional groups are beneficial for high stability. Finally, PSCs based on 3,3,3‐trifluoropropyltrimethoxysilane (FPTMS) modification showed a high PCE of 23.0% with the best operational stability. The encapsulated device maintained 85% of the initial PCE after 1725 h under continuous 1 sun equivalent illumination in air. The work may provide important insights into designing modifiers for high‐performance PSCs with high stability. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) perovskites show structural stability and tunability and are regarded as promising photovoltaic materials. The spacer cations play an important impact on exciton separation and charge transport of 2D perovskites. Herein, a novel spacer with thiazole as core, 2‐thiazolemethanammonium (AMT), owning characters of small molecular size, delocalized π‐electrons, and strong electron‐withdrawing ability, is introduced to construct 2D DJ perovskites. Owing to the strong orbital coupling between AMT spacer and inorganic layers, the AMT‐based perovskite exhibits type II quantum well structure, which is favorable for exciton separation. On contrary, such interaction does not appear in the DJ perovskite when aliphatic propyldiammonium (PDA), with a similar length, is used as spacer. The AMT spacer can also induce better crystallinity, resulting in reduced defect density and improved charge transport ability. The optimized device based on (AMT)MA3Pb4I13 exhibits a power conversion efficiency (PCE) of 19.69%, which is a record for 2D DJ perovskite solar cells (PSCs) (n ≤ 4). This work provides deep understanding of the impact of aromatic spacer on the electronic structure of 2D DJ perovskites and the corresponding photovoltaic performance and provides a new opportunity toward highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Examines the scientific development of organic composite photoconductive materials and devices. Spectral response region of inter-molecular composites; Photosensitivity of intra-molecular composites; Effects of the charge-transfer through the two kinds of photoconductive composites.

2D Dion–Jacobson (2D DJ) perovskites are considered as promising photovoltaic materials due to their structural stability and spacer designability. Here, a spacer cation with an aromatic imidazole ring, 2‐(1H‐imidazol‐2‐yl)ethylammonium (HE), is successfully applied to construct 2D DJ perovskite. It's found that the high polarity of the HE spacer strengthens the interaction between organic and inorganic layers and reduces the exciton binding energy to 67.8 meV, resulting in promoted charge dissociation, compared with the aliphatic 1,4‐butanediammonium (BDA) spacer with a similar length. The HE spacer enlarges the micelle size in precursor solution and suppresses the formation of low‐n value phases. In consequence, the HE‐based perovskite film exhibits better quality than the BDA‐based one, with lower defect density and longer carrier lifetime. The optimized device based on (HE)(MA0.75FA0.25)4Pb5I16 film achieves a champion power conversion efficiency up to 18.40%, much higher than that of the BDA‐based device (15.03%). Besides, the unencapsulated device based HE exhibits improved moisture and thermal stability. [ABSTRACT FROM AUTHOR]

Nickel oxide is one of the most promising hole‐transporting materials in inverted perovskite solar cells (PSCs) but suffers from undesired reactions with perovskite which leads to limited device performance and stability. Self‐assembled monolayers (SAMs) are demonstrated to effectively optimize the NiOx/perovskite interface, but the significance of the compactness of the SAM at the interface is less investigated. Here, a series of methoxy‐substituted triphenylamine functionalized benzothiadiazole (TBT) based SAM molecules, TBT‐BA, TBT‐FBA, and TBT‐DBA, with benzoic acid, 2‐fluorobenzoic acid and isophthalic acids as anchoring groups are used to modify NiOx. TBT‐BA with the simplest structure is demonstrated to form the densest SAM on NiOx, thus optimized NiOx/SAM/perovskite interface is achieved with enhanced charge collection and suppressed interfacial reaction and recombination. TBT‐BA can also passivate the perovskite most effectively due to the highest binding energy toward perovskite, thus the corresponding inverted PSCs show the highest PCE of 24.8% and maintain 88.7% of the initial PCE after storage at 60 °C for 2635 h in the glovebox. The work provides important insights into designing SAM molecules for modification transporting layers for efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) hold immense potential as renewable energy sources, but the performance‐stability conundrum remains a major obstacle on the road to OSC commercialization. To address this, in this study, molecular packing behaviors of representative state‐of‐the‐art Y‐series non‐fullerene acceptors (NFAs) are studied, focusing on their terminal group symmetries. Utilizing grazing‐incidence wide‐angle X‐ray scattering, the distinct crystalline packing structure of these NFAs is revealed. Remarkably, NFAs with asymmetric terminals exhibited excellent additive insensitivity and thermal stability for their crystalline structure, unlike their symmetric counterparts. Molecular dynamics simulations confirmed the stable and robust crystalline feature of asymmetric NFAs and attributed to their large molecular dipole moments. These findings showed the great potential of asymmetric NFAs in fabricating efficient and intrinsically stable additive‐free OSC devices for real applications. [ABSTRACT FROM AUTHOR]

The growth of disorganized lithium dendrites and weak solid electrolyte interphase greatly impede the practical application of lithium metal batteries. Herein, we designed and synthesized a new kind of stable polyimide covalent organic frameworks (COFs), which have a high density of well‐aligned lithiophilic quinoxaline and phthalimide units anchored within the uniform one‐dimensional channels. The COFs can serve as an artificial solid electrolyte interphase on lithium metal anode, effectively guiding the uniform deposition of lithium ions and inhibiting the growth of lithium dendrites. The unsymmetrical Li||COF−Cu battery exhibits a Coulombic efficiency of 99 % at a current density of 0.5 mA cm−2, which can be well retained up to 400 cycles. Meanwhile, the Li‐COF||LFP full cell shows a Coulombic efficiency over 99 % at a charge of 0.3 C. And its capacity can be well maintained up to 91 % even after 150 cycles. Therefore, the significant electrochemical cycling stability illustrates the feasibility of employing COFs in solving the disordered deposition of lithium ions in lithium metal batteries. [ABSTRACT FROM AUTHOR]

The growth of disorganized lithium dendrites and weak solid electrolyte interphase greatly impede the practical application of lithium metal batteries. Herein, we designed and synthesized a new kind of stable polyimide covalent organic frameworks (COFs), which have a high density of well‐aligned lithiophilic quinoxaline and phthalimide units anchored within the uniform one‐dimensional channels. The COFs can serve as an artificial solid electrolyte interphase on lithium metal anode, effectively guiding the uniform deposition of lithium ions and inhibiting the growth of lithium dendrites. The unsymmetrical Li||COF−Cu battery exhibits a Coulombic efficiency of 99 % at a current density of 0.5 mA cm−2, which can be well retained up to 400 cycles. Meanwhile, the Li‐COF||LFP full cell shows a Coulombic efficiency over 99 % at a charge of 0.3 C. And its capacity can be well maintained up to 91 % even after 150 cycles. Therefore, the significant electrochemical cycling stability illustrates the feasibility of employing COFs in solving the disordered deposition of lithium ions in lithium metal batteries. [ABSTRACT FROM AUTHOR]

2D/3D‐structured perovskites are promising for high‐performance and stable solar cells due to the passivation ability and hydrophobic character of the large organic cations. However, most of the 2D/3D‐structured perovskites prepared by adding ammonium halides into the precursors or depositing ammonium halides on top of a 3D perovskite film ignore the buried interface which is crucial for the device efficiency and stability. Here, 2D/3D/2D‐structured perovskite films with optimized buried interface are constructed by depositing phenethylammonium bromide (PEABr) on top and 2D perovskite PEA2FA2Pb3Br10 at the bottom of 3D Cs0.07FA0.85MA0.08Pb(I0.95Br0.05)3 perovskite. Thus, a power conversion efficiency (PCE) of 24.2% is achieved due to the minimal nonradiative recombination. The encapsulated device also shows an improved stability, maintaining 93.5% of the initial value after 1000 h under 1 sun equivalent illumination at the maximum power point. This strategy may provide important insights into designing perovskite film structures to achieve high‐performance solar cells with high stability. [ABSTRACT FROM AUTHOR]

Simultaneously achieving improvements in power conversion efficiency (PCE) and stability is the main task of the current development stage of organic solar cells (OSCs). This work reports a symmetry–asymmetry dual‐acceptor (SADA) strategy to construct ternary devices, which is found to be feasible for increasing both the PCE and the operational lifetime of OSCs. In this contribution, the symmetric acceptor L8‐BO and the asymmetric acceptor BTP‐S9 are blended in equal proportions with polymer donor PM6 for the consideration of absorption spectrum complementarity and cascade energetic alignment. In addition, the features of crystallinity and miscibility of the dual‐acceptor deliver optimized morphology lead to a high PCE of 18.84%. In addition, the asymmetric acceptor BTP‐S9 with a larger dipole moment shows tighter molecular stacking and longer crystal correlation length, which favor intrinsic molecular photostability, and further consolidate the operational lifetime of OSCs when coordinated with L8‐BO. This work demonstrates the efficacy of the SADA strategy for constructing efficient and stable OSCs. [ABSTRACT FROM AUTHOR]

Smooth perovskite film with high crystallinity and vertical orientation is highly favored for high‐performance quasi‐2D perovskite solar cells (PVSCs), yet limited by the critical balance between nucleation and crystal growth. To address this issue, here a fast solidification and slow growth (FSSG) strategy is developed to effectively optimize the film morphology. The fast solidification enables a smooth, pinhole‐free film, while slow growth allows it to further ripen into high‐crystallinity film. This process is enabled by the low‐boiling point solvent system, that is, acetonitrile, with high‐boiling point additives, that is, NH4SCN and CH3NH3Cl. Compared to the traditional method, uniform film with a larger grain/crystallite size as well as better crystallinity can be easily fabricated through this FSSG strategy. As a result, the quasi‐2D PVSCs based on (GA)2(MA)4Pb5I16 processed with the FSSG strategy show a champion power conversion efficiency of 20.44%, as well as 19.08% for large‐area (1 cm2) devices, which suggest the capability of the FSSG strategy for up‐scaled PVSC fabrication. Therefore, this work opens a new avenue toward morphology control of PVSCs for practical applications. [ABSTRACT FROM AUTHOR]

Highlights: A solid additive-assisted layer-by-layer (SAA-LBL) processing was developed to facilitate the inter-diffusion between polymer donor and acceptor and optimize the morphology of quasi-planar heterojunction for high-performance organic solar cells (OSCs). The pre-phase separation between fatty acid and polymer donor, easily tuned via controlling the cohesive energy, is critical to form the desired vertical phase-separation morphology. The SAA-LBL is generally applicable to various OSC systems, and enables the record efficiency of 19.02% among the binary OSCs. Morphology is of great significance to the performance of organic solar cells (OSCs), since appropriate morphology could not only promote the exciton dissociation, but also reduce the charge recombination. In this work, we have developed a solid additive-assisted layer-by-layer (SAA-LBL) processing to fabricate high-efficiency OSCs. By adding the solid additive of fatty acid (FA) into polymer donor PM6 solution, controllable pre-phase separation forms between PM6 and FA. This intermixed morphology facilitates the diffusion of acceptor Y6 into the donor PM6 during the LBL processing, due to the good miscibility and fast-solvation of the FA with chloroform solution dripping. Interestingly, this results in the desired morphology with refined phase-separated domain and vertical phase-separation structure to better balance the charge transport /collection and exciton dissociation. Consequently, the binary single junction OSCs based on PM6:Y6 blend reach champion power conversion efficiency (PCE) of 18.16% with SAA-LBL processing, which can be generally applicable to diverse systems, e.g., the PM6:L8-BO-based devices and thick-film devices. The efficacy of SAA-LBL is confirmed in binary OSCs based on PM6:L8-BO, where record PCEs of 19.02% and 16.44% are realized for devices with 100 and 250 nm active layers, respectively. The work provides a simple but effective way to control the morphology for high-efficiency OSCs and demonstrates the SAA-LBL processing a promising methodology for boosting the industrial manufacturing of OSCs. [ABSTRACT FROM AUTHOR]

2D perovskites have attracted intensive attention by virtue of their excellent optical and electrical properties along with good stabilities. Herein, a highly sensitive self‐powered photodiode based on (PEA)2(MA)4Pb5I16 (PEA=C6H5(CH2)NH3, MA=CH3NH3) 2D perovskite is demonstrated by dual interface passivations. The Al2O3 bottom passivation can reduce the pinhole defects in the 2D perovskite film and suppress the trap‐related recombination loss, bringing forward much reduced dark current and increased photocurrent. The poly (methyl methacrylate) (PMMA) top passivation can encapsulate the 2D perovskite film and thus improve the stability of the device. These results show that the 2D perovskite‐based photodiode with dual interface passivations exhibits a large photo‐to‐dark current ratio of 107, a fast response speed of 597 ns and a linear dynamic range of 160 dB without bias. Responsivity (R) and detectivity (D*) respectively reach 0.36 A W−1 and 5.4 × 1012 Jones under 532 nm laser illumination at a power density of 1.5 nW cm−2. Moreover, the dual interface passivated device exhibits good stabilities. This study paves the road for developing low‐cost, low‐power, solution processed image sensors. [ABSTRACT FROM AUTHOR]

The inorganic perovskite solar cells (IPSC) are promising in the context of simultaneously delivering high efficiency and good stability. Developing a high‐performance and larger band gap IPSC is particularly in demand for commercialization due to their suitability to match with the prevailing silicon solar cells for tandem devices, while this is hindered by the poor morphology and phase stability of inorganic perovskite films. To address this issue, this work develops a combined method of nonstoichiometric composition and post‐cation exchange to improve the morphology and phase stability of the CsPbI2Br IPSCs, and achieves a record efficiency of 17.80%. This work finds that excessive PbI2 regulates the CsPbI2Br film crystallization, and thus, a high‐quality perovskite film with enlarged grains is obtained. Further depositing the formamidinium iodide on top of the CsPbI2Br perovskite induces cation exchange during the post‐annealing process, which increases the phase stability of the perovskite film and significantly improves the device efficiency and stability. Therefore, this work provides an avenue toward high‐performance IPSCs, via the nonstoichiometric and ion exchange method. [ABSTRACT FROM AUTHOR]

PBT and PET are subjected to thermal-oxidative degradation and thermomechanical degradation during the process of melt blending, which affect the polymer structure and properties. The effect of feed properties of PET and the addition of modified nanoparticles on blends are a question worthy of discussion. This work describes the melting and thermal stability, the crystallization behavior and non-isothermal crystallization kinetic, the rheological behaviors and mechanical properties of several PBT/PET blends prepared by twin-screw melt extrusion. Results show that the molecular chain of the polyester blends obtained by stable extrusion are not significantly degraded, there is only one obvious melting peak and crystallization peak on the thermal analysis curves, and the melting point is lower than either of the two polyesters. An appropriate amount of SD can effectively reduce the crystallization rate of the PBT material and extend the crystallization time. The rheological behavior of PBT/PET blends is complicated than PET raw materials and SD, as well as the melt processing temperature and shear rate will all affect the rheological behavior of the blends. For example, at low shear rate, polyester blends with SD exhibit strong shear thinning behavior. In general, the SD content affects the rheological property of blends in a way similar to the law of influence on crystallization behavior. When SD content is 0.3 wt%, a polyester product with higher elongation at break than pure PBT can be obtained. This can provide a useful reference for preparing commercialized polyester blend products with good melt processability and elongation by simple blending. [ABSTRACT FROM AUTHOR]

Chemical vapor deposition on metal substrates using gaseous hydrocarbon as carbon feedstock has proven to be a feasible way for synthesis of large-area and uniform graphene films. Meanwhile, rearrangement of amorphous carbon species extracted from solid carbon sources into crystalline graphene not only offers an alternative route for graphene growth but also provides a powerful tool to excavate the underlying mechanisms of graphene formation. In this review, we discuss the processes of extracting carbon species from various solid carbon sources to form graphene. We summarize the typical steps of solid carbon sources to graphene transition and evaluate the resultant graphene film quality with regard to electrical performance. Unveiling the detailed solid carbon to graphene transition process paves the way for a reproducible production of graphene with controlled layer number, defect type and density, toward the final end of graphene's commercial utilizations with low cost. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The surface properties and chemical interactions are critical for perovskite solar cells (PVSCs). In this work, we show that the polypropylene glycol (PPG) can simultaneously passivate the NiOx surface and grain boundaries of perovskite films, allowing more efficient charge transfer at the anode interface and reducing the recombination of PVSCs. As a result, the open‐circuit voltage (Voc) of MAPbI3 based inverted PVSCs increases from 1.087 V to 1.127 V, and the short‐circuit current density (Jsc) is increased from 20.87 mA·cm–2 to 22.32 mA·cm–2, thereby realizing the improvement of the device power conversion efficiency (PCE) from 18.34% to 20.12%. Moreover, the steady‐state output of the PVSCs is remarkably improved by incorporating PPG. Further analysis of surface properties suggests that part of the PPG at the interface can permeate into the precursor solution with the help of DMF solvent and remain in the perovskite layer to form a concentration gradient. The ether bond of PPG and the uncoordinated Pb2+ in the perovskite are coordinated to achieve passivation effects and improve device performance. Our work provides a rational strategy for the preparation of high‐performance PVSCs. [ABSTRACT FROM AUTHOR]

Balancing and improving the open‐circuit voltage (Voc) and short‐circuit current density (Jsc) synergistically has always been the critical point for organic photovoltaics (OPVs) to achieve high efficiencies. Here, this work adopts a ternary strategy to regulate the trade‐off between Voc and Jsc by combining the symmetric‐asymmetric non‐fullerene acceptors that differ at terminals and alkyl side chains to build the ternary OPV (TOPV). It is noticed that the reduced energy disorder and the enhanced luminescence efficiency of TOPV enable a mitigated energy loss and a higher Voc. Meanwhile, the third component, which is distributed at the host donor–acceptor interface, acts as the charge transport channel. The prolonged exciton lifetime, the boosted charge mobility, and the depressed charge recombination promote the TOPV to obtain an improved Jsc. Finally, with synergistically improved Voc and Jsc, the TOPV delivers an optimal efficiency of 19.26% (certified as 19.12%), representing one of the highest values reported so far. [ABSTRACT FROM AUTHOR]

Ternary strategy, adding an additional donor (D) or acceptor (A) into conventional binary D:A blend, has shown great potential in improving photovoltaic performances of organic photovoltaics (OPVs) for practical applications. Herein, this review is presented on how efficient ternary OPVs are realized from the aspects of morphology, energy loss, and working mechanism. As to morphology, the role of third component on the formation of preferred alloy‐like‐phase and vertical‐phase, which are driven by the miscibility tuning, is discussed. For energy loss, the effect of the third component on the luminescence enhancement and energetic disordering suppression, which lead to favorable increase of voltage, is presented. Regarding working mechanism, dilution effect and relationships between two acceptors or donor/acceptor, which explain the observed device parameters variations, are analyzed. Finally, some future directions concerning ternary OPVs are pointed out. Therefore, this review can provide a comprehensive understanding of working principles and effective routes for high‐efficiency ternary systems, advancing the commercialization of OPVs. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) show the potential to harness solar energy at a lower cost and in a greener way with the merits of mechanical flexibility and potential low‐cost upscaling production with solution processing. Meanwhile, the common use of toxic halogenated solvents causes pollution to the natural environment, and thus, needs to be avoided. Following the authors' previous work on the design of top‐illuminated ultrathin Ag‐based device structure highlighting most merits of OSC, herein non‐halogen solvent and additive processing OSCs are presented, which exhibit high power conversion efficiency (PCE) of 17.64%, close to the best PCE with the commonly used halogen solvent. Interestingly, it is observed that the additive and the multicomponent strategy (blending third component BTP‐S2 into PM6:L8‐BO binary blend) synergistically affect the optimal morphology and device performance. Finally, OSC devices featuring green solvent processing, indium tin oxide‐free, flexibility, and upscaling merits are fabricated and exhibit the best PCE of 13.76% with high mechanical robustness and good stability against heat or light illumination. This work provides a prospective potential for manufacturing the OSC toward practical applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] We achieved a highest hole mobility. [•] We made single crystals by Droplet Pinned Crystallization (DPC) method. [•] We compare the devices on the basis of grown single crystal step heights. [•] We observe the ambipolar transport phenomenon in the devices. [ABSTRACT FROM AUTHOR]

Balancing the charge generation and recombination constitutes a major challenge to break the current limit of organic photovoltaics (OPVs). To address this issue, an asymmetric non‐fullerene acceptor, namely the AC9, is developed and high‐performance OPV with a champion efficiency of 18.43% (18.1% certified) is demonstrated. This represents the record value among binary OPVs. Comprehensive analysis on exciton dissociation, charge collection, carrier transport, and recombination has been carried out, unveiling that the improved device performance of asymmetric AC9‐based OPVs is originated from a better compromise between charge generation and non‐radiative charge recombination, compared with the corresponding symmetric ones. This work provides a high‐performing molecule and paves the way for high‐performance OPVs through asymmetric molecular design. [ABSTRACT FROM AUTHOR]

Abstract: Stable, elastic and optical transparent microcapsules containing tetrachloroethylene as core material were prepared from gelatin, sodium dodecyl sulfate (SDS) and sodium carboxymethylcellulose (NaCMC) by complex coacervation method for electrophoretic display. Microcapsules were characterized by scanning electron microscopy, optical microscopy, and thermogravimetric analysis. It is suggested that SDS plays an important role during the process of microencapsulation, i.e. the existence of SDS increases the interaction between gelatin and NaCMC and facilitates the progress of complex coacervation. Because of the compact structure of the capsule wall, the microcapsules represent high thermal stability and good barrier property, both of which prevent core materials from penetrating outside the capsules. [Copyright &y& Elsevier]

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]

Although the 2D spacer modification is widely studied in perovskite solar cells (PVSCs), the energy level alignment between the 2D/3D interfaces makes it unfavorable for top surface passivation in the inverted p‐i‐n device structure. To address this issue, the effect of bottom interface modification is studied with three representative 2D spacers, i.e., the Ruddlesden‐Popper 2D spacer, Dion‐Jacobson 2D spacer, and strong passivation 2D spacer, in inverted p‐i‐n PVSCs. After optimization, the PVSCs with these 2D spacer modifications universally exhibit the best efficiencies of ≈21.6%, which constitutes dramatic improvement compared to the control device (20.7%). By lifting off the perovskite layer, the optoelectronic properties of the bottom surface are studied, and the mechanism underlying the improved device performance is unveiled to be uniformly originated from the formation of 2D/3D heterojunction, where the cascade valence band facilitates the hole collection and electron back scattering field suppresses the charge recombination at the anode interface. Besides, the unencapsulated device retains 90% of initial efficiency after 30 days of storage in ambient air with a relative humidity of 30 ± 5%, indicating excellent stability against moisture and oxygen. This study provides insight into the bottom interface modification with diverse 2D spacers for high‐performance p‐i‐n structured PVSC devices. [ABSTRACT FROM AUTHOR]

The spectral selective detection of the near‐infrared (NIR) signals is important for biological sensing, healthy monitoring, and intelligent communication. Herein, a new method to fabricate a visible‐blind NIR‐sensitive narrowband photodetector (NPD) with excellent comprehensive performances is reported. The organic bulk heterojunction (OBHJ) thin film, based on an NIR‐sensitive organic acceptor, is employed to provide fast photoresponse, with adjustable cutoff edge. The key strategy of introducing a solution‐processable optical/electric bifunctional internal filter (CH3NH3PbI3 (MAPbI3)/CuSCN) realizes the selective collection of the NIR‐induced charge carriers. Further combined with the suitable energy level and high mobility of the MAPbI3/CuSCN layer, the extraction of NIR‐light‐induced charges from OBHJ is promoted efficiently. The NPD with optimized structure exhibits narrowband NIR response (full width at half maximum (FWHM) < 100 nm) with maximum external quantum efficiency value up to 74.26% and detection limit down to 3.6 pW cm−2, both of which are the best values among the ever reported NIR NPDs. The highest responsivity reaches 0.485 A W−1 in the NIR region, with a large linear dynamic range of 162 dB. The specific detectivity is close to 1013 Jones, enabling the device to detect weak NIR signals. [ABSTRACT FROM AUTHOR]

Despite the remarkable progress achieved in recent years, organic photovoltaics (OPVs) still need work to approach the delicate balance between efficiency, stability, and cost. Herein, two fully non‐fused electron acceptors, PTB4F and PTB4Cl, are developed via a two‐step synthesis from single aromatic units. The introduction of a two‐dimensional chain and halogenated terminals for these non‐fused acceptors plays a synergistic role in optimizing their solid stacking and orientation, thus promoting an elongated exciton lifetime and fast charge‐transfer rate in bulk heterojunction blends. As a result, PTB4Cl, upon blending with PBDB‐TF polymer, has enabled single‐junction OPVs with power conversion efficiencies of 12.76 %, representing the highest values among the reported fully unfused electron acceptors so far. [ABSTRACT FROM AUTHOR]

Despite the remarkable progress achieved in recent years, organic photovoltaics (OPVs) still need work to approach the delicate balance between efficiency, stability, and cost. Herein, two fully non‐fused electron acceptors, PTB4F and PTB4Cl, are developed via a two‐step synthesis from single aromatic units. The introduction of a two‐dimensional chain and halogenated terminals for these non‐fused acceptors plays a synergistic role in optimizing their solid stacking and orientation, thus promoting an elongated exciton lifetime and fast charge‐transfer rate in bulk heterojunction blends. As a result, PTB4Cl, upon blending with PBDB‐TF polymer, has enabled single‐junction OPVs with power conversion efficiencies of 12.76 %, representing the highest values among the reported fully unfused electron acceptors so far. [ABSTRACT FROM AUTHOR]

The poor electrical conductivity of two‐dimensional (2D) crystalline frameworks greatly limits their utilization in optoelectronics and sensor technology. Herein, we describe a conductive metallophthalocyanine‐based NiPc‐CoTAA framework with cobalt(II) tetraaza[14]annulene linkages. The high conjugation across the whole network combined with densely stacked metallophthalocyanine units endows this material with high electrical conductivity, which can be greatly enhanced by doping with iodine. The NiPc‐CoTAA framework was also fabricated as thin films with different thicknesses from 100 to 1000 nm by the steam‐assisted conversion method. These films enabled the detection of low‐concentration gases and exhibited remarkable sensitivity and stability. This study indicates the enormous potential of metallophthalocyanine‐based conductive frameworks in advanced stand‐off chemical sensors and provides a general strategy through tailor‐make molecular design to develop sensitive and stable chemical sensors for the detection of low‐concentration gases. [ABSTRACT FROM AUTHOR]

The poor electrical conductivity of two‐dimensional (2D) crystalline frameworks greatly limits their utilization in optoelectronics and sensor technology. Herein, we describe a conductive metallophthalocyanine‐based NiPc‐CoTAA framework with cobalt(II) tetraaza[14]annulene linkages. The high conjugation across the whole network combined with densely stacked metallophthalocyanine units endows this material with high electrical conductivity, which can be greatly enhanced by doping with iodine. The NiPc‐CoTAA framework was also fabricated as thin films with different thicknesses from 100 to 1000 nm by the steam‐assisted conversion method. These films enabled the detection of low‐concentration gases and exhibited remarkable sensitivity and stability. This study indicates the enormous potential of metallophthalocyanine‐based conductive frameworks in advanced stand‐off chemical sensors and provides a general strategy through tailor‐make molecular design to develop sensitive and stable chemical sensors for the detection of low‐concentration gases. [ABSTRACT FROM AUTHOR]

Semi‐transparent organic photovoltaics (ST‐OPVs) are promising solar windows for building integration. Improving the light‐absorbing selectivity, that is, transmitting the visible photons while absorbing the invisible ones, is a key step toward high‐performance ST‐OPV. To achieve this goal, the optical properties of the active layer, transparent electrode, and capping layer are comprehensively tailored, and a highly efficient ST‐OPV with good absorbing selectivity is demonstrated. First, a numerical method is established to quantify the absorbing selectivity of materials and devices, based on which, an infrared absorbing non‐fullerene acceptor, that is, H3, is selected among a large pool of photo‐active materials. Second, an ultra‐smooth transparent thin Ag layer with small granule size is developed via polyethylenimine wetting, which alleviates light scattering and improves the electric properties for ST‐OPV. Finally, as guided by optical simulation, a TeO2 capping layer is deposited on top of the ultra‐thin Ag to further improve the light‐absorbing selectivity. As a result, the light utilization efficiency is significantly improved to 3.95 ± 0.02% (best ≈4.06%), with a good color rendering index of 76.85. These results make it one of the best among color‐neutral ST‐OPVs. This work stresses the importance of manipulating the light‐absorbing selectivity for high‐performance ST‐OPVs. [ABSTRACT FROM AUTHOR]

Abstract: TiO2 has wide applications in chemical industry. In this manuscript we describe the ordered TiO2 nanoribbon arrays fabricated by electrospinning. A modified collector with a pair of split electrodes was employed to collect the TiO2 nanoribbon arrays during the electrospinning. The morphology and the structure of the resulting arrays were analyzed by scanning electron micrograph. It was found that the morphology of the aligned TiO2 ribbon arrays could be controlled by the spinneret geometry and the applied voltage. The ordered degree of the aligned TiO2 nanoribbon arrays could also be controlled by the environmental relative humidity. [Copyright &y& Elsevier]

2D perovskite solar cells (2D PVSCs) show good stability for commercialization. However, their power conversion efficiency (PCE) is relatively low. In this work, a post‐treatment strategy by simultaneously applying light and heat to quasi‐2D PVSCs, obtaining a record PCE of 18.24% is developed. It is found that heat‐treating PVSCs in the dark slightly increases the device performance over time at temperatures below 75 °C, whereas the performance deteriorates rapidly at temperatures above 100 °C. Upon illumination, the device efficiency is significantly improved, particularly when the thermal‐treatment temperature is increased to 100 °C. A comprehensive carrier dynamic study reveals that the enhanced performance can be attributed to the reduced quasi‐2D perovskite defect states and improved charge collection. In addition, this strategy enables better stability, and an unencapsulated device can retain 90% of its original PCE after 1340 h of direct exposure to air with a humidity of 50 ± 5%. Thus, the strategy paves the way for the commercialization of quasi‐2D PVSCs. [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]

Summary of main observation and conclusion: The small organic molecular Dioctylbenzothienobenzothiophene (C8‐BTBT) has been explored as hole transport material (HTM) to replace PEDOT:PSS in inverted perovskite solar cells (PVSCs). MAPbI3 perovskite films depositd onto C8‐BTBT are smooth and uniform, with negligible residual of PbI2 and large grain size even larger than 1 μm. Our champion C8‐BTBT based devices reached a high power conversion efficiency (PCE) of 15.46% with marginal hysteresis, much higher than that of 11.50% achieved using PEDOT:PSS. Besides, devices adopting C8‐BTBT as substrate show superior stability compared with the PEDOT:PSS based devices when stored under ambient conditions with a relative humidity of (25±5)%. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: As an environmentally friendly perovskite material with low bandgap, Tin (Sn)‐based perovskite has drawn much attention. A simple and effective method for fabricating high‐quality Sn‐Pb binary perovskite film is highly desired. Here, with methylammonium chloride (MACl) post‐treatment to assist vertical recrystallization, we fabricated high quality FA0.75Cs0.25Pb0.5Sn0.5I3 perovskite film via one‐step processing method. This recrystallization method was first used in Sn‐based perovskite. The obtained film consists of vertically aligned grains with high crystallinity, which contributes to a power conversion efficiency (PCE) of 14.03% in corresponding perovskite solar cell (PVSC). The cells maintained 80% of their initial PCEs after being stored for 30 d in glove‐box. This simple, effective method provides an easy way to fabricate high performance Sn‐Pb binary PVSC. [ABSTRACT FROM AUTHOR]

The fabrication of high‐quality film with large grains oriented along the direction of film thickness is important for 2D Ruddlesden–Popper perovskite‐based solar cells (PVSCs). High‐quality 2D BA2MAn−1PbnI3n+1 (BA+=butylammonium, MA+=methylammonium, n=5) perovskite films were fabricated with a grain size of over 1 μm and preferential orientation growth by introducing a second spacer cation (SSC+) into the precursor solution. Dynamic light scattering showed that SSC+ addition can induce aggregation in the precursor solution. The precursor aggregates are favorable for the formation of large crystal grains by inducing nucleation and decreasing the nucleation sites. Applying phenylethylammonium as SSC+, the optimized inverted planar PVSCs presented a maximum PCE of 14.09 %, which is the highest value of the 2D BA2MAn−1PbnI3n+1 (n=5) PVSCs. The unsealed device shows good moisture stability by maintaining around 90 % of its initially efficiency after 1000 h exposure to air (Hr=25±5 %). [ABSTRACT FROM AUTHOR]

The fabrication of high‐quality film with large grains oriented along the direction of film thickness is important for 2D Ruddlesden–Popper perovskite‐based solar cells (PVSCs). High‐quality 2D BA2MAn−1PbnI3n+1 (BA+=butylammonium, MA+=methylammonium, n=5) perovskite films were fabricated with a grain size of over 1 μm and preferential orientation growth by introducing a second spacer cation (SSC+) into the precursor solution. Dynamic light scattering showed that SSC+ addition can induce aggregation in the precursor solution. The precursor aggregates are favorable for the formation of large crystal grains by inducing nucleation and decreasing the nucleation sites. Applying phenylethylammonium as SSC+, the optimized inverted planar PVSCs presented a maximum PCE of 14.09 %, which is the highest value of the 2D BA2MAn−1PbnI3n+1 (n=5) PVSCs. The unsealed device shows good moisture stability by maintaining around 90 % of its initially efficiency after 1000 h exposure to air (Hr=25±5 %). [ABSTRACT FROM AUTHOR]