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Combining the merits of battery and supercapacitor into a single device represents a major scientific and technological challenge. From a design perspective, electrode material plays a key role in the device and the fundamental difficulty lies in incorporating a high density of active sites into a stable material with excellent charge transfer kinetics. Here, the synthesis is reported of a nearly full‐oxygen‐functionalized 2D conductive transition metal carbide (Ti3C2Oy) with ultrahigh density of Ti─O/═O redox‐active sites by nucleophilic substitution and in situ oxidation under the presence of a proper electrophilic reagent (K+). The fabricated electrode delivered exceptionally high gravimetric and volumetric capacitance (1,082 F g−1 and 3,182 F cm−3 in a potential window of 0.85 V, approximating the theoretical capacity of many transition metal oxides), fast charging/discharging in tens of seconds across a wide range of temperature (−70 to 60 °C), and excellent structural and chemical stability. These promising results provide avenues for the development of high‐energy, high‐power storage devices as well as electromagnetic shielding, and electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Yarn artificial muscles offer an exciting avenue to replicate the extraordinary efficiency of biological muscles, converting chemical energy directly into mechanical work. Nevertheless, realizing the chemical‐mechanical energy conversion has posed significant challenges. In this study, a novel approach for harnessing direct catalysis to power yarn artificial muscles within a one‐compartment aqueous system is introduced. This research distinguishes itself through an innovative actuation mechanism using nanoscale catalytic particles. These nanoparticles synthesized and integrated onto the yarn surface act as a chemical trigger for muscle actuation. Notably, the resulting yarn muscle demonstrates a reversible tensile stroke of nearly 4% in ≈20 s. By bridging the gap between chemical catalysis and mechanical performance, this study paves the way for innovative applications in fields ranging from robotics to biomedical devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) transition-metal carbide Ti3C2TX (MXene) possesses good electrical conductivity, high specific surface areas and metal oxide-like surfaces, which make it ideal for application in supercapacitors with both high energy density and power density. However, similar to other 2D materials, the issue of self-stacking leads to narrower ion-transport channels, along with a drastic reduction in active sites, thus severely limiting the performance of MXene-based electrodes. To address this problem, this work proposes to introduce one-dimensional (1D) reduced graphene oxide (rGO) nanoribbons as spacers between MXene nanosheets to construct a composite structure for inhibiting self-stacking. As expected, owing to the steric effect and high aspect ratio of rGO nanoribbons, the fabricated MXene/rGO hybrid electrode, with the addition of 5 wt% graphene oxide (GO), exhibits a greatly improved specific capacitance (397.4 F g−1 at 5 mV s−1) and an unparalleled rate capability (with a capacitance retention of 52.9% at 2000 mV s−1). This work sheds significant light on the development of MXene-based materials for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

Various isomers have been developed to regulate the morphology and reduce defects in state‐of‐the‐art perovskite solar cells (PSCs). To insight the structure‐function‐effect correlations for the isomerization of thiourea derivatives on the performance of the PSCs, we developed two thiourea derivatives [(3,5‐dichlorophenyl)amino]thiourea (AT) and N‐(3,5‐dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two −NH− groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high‐quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT‐treated FACsPbI3 device engenders an efficiency of 25.71 % (certified as 24.66 %), which is greatly higher than control (23.74 %) and HB‐treated FACsPbI3 devices (25.05 %). The resultant device exhibits a remarkable stability for maintaining 91.0 % and 95.2 % of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively. [ABSTRACT FROM AUTHOR]

Various isomers have been developed to regulate the morphology and reduce defects in state‐of‐the‐art perovskite solar cells (PSCs). To insight the structure‐function‐effect correlations for the isomerization of thiourea derivatives on the performance of the PSCs, we developed two thiourea derivatives [(3,5‐dichlorophenyl)amino]thiourea (AT) and N‐(3,5‐dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two −NH− groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high‐quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT‐treated FACsPbI3 device engenders an efficiency of 25.71 % (certified as 24.66 %), which is greatly higher than control (23.74 %) and HB‐treated FACsPbI3 devices (25.05 %). The resultant device exhibits a remarkable stability for maintaining 91.0 % and 95.2 % of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively. [ABSTRACT FROM AUTHOR]

Wide‐bandgap perovskite solar cells (WBG‐PSCs) are pivotal in achieving high‐performance tandem solar cells. However, their power conversion efficiency (PCE) is limited by the losses from the interfacial charge transfer barrier and nonradiative recombination. In this investigation, 1,4‐bis(aminomethyl)benzene (PDMA) is employed as a defect passivator for fabricating methylammonium (MA)‐free perovskite solar cells (PSCs), thus effectively mitigating nonradiative recombination losses of charge carriers. Meanwhile, PDMA molecules chemically rinse the perovskite film to create a grooved surface, leading to the increase of contact area between the perovskite and electron transport layer to further improve the interfacial charge transfer. As a result, the PSCs based on these surface‐passivated and chemically cleaned perovskite films present a champion PCE of 21.23% (Eg = 1.68 eV) compared to the control devices with a PCE of 18.23%, while maintaining over 80% efficiency after 800 h storage in ambient air. This study presents a highly effective approach for one‐step passivation and chemical cleaning of wide‐bandgap perovskite for efficient and stable solar cells, offering valuable insights for future research in this field. [ABSTRACT FROM AUTHOR]

Efficiency reduction in perovskite solar cells (PSCs) during the magnification procedure significantly hampers commercialization. Vacuum‐flash (VF) has emerged as a promising method to fabricate PSCs with consistent efficiency across scales. However, the slower solvent removal rate of VF compared to the anti‐solvent method leads to perovskite films with buried defects. Thus, this work employs low‐toxic Lewis base ligand solvent N‐ethyl‐2‐pyrrolidone (NEP) to improve the nucleation process of perovskite films. NEP, with a mechanism similar to that of N‐methyl‐2‐pyrrolidone in FA‐based perovskite formation, enhances the solvent removal speed owing to its lower coordination ability. Based on this strategy, p–i–n PSCs with an optimized interface attain a power conversion efficiency (PCE) of 24.19% on an area of 0.08 cm2. The same nucleation process enables perovskite solar modules (PSMs) to achieve a certified PCE of 23.28% on an aperture area of 22.96 cm2, with a high geometric fill factor of 97%, ensuring nearly identical active area PCE (24%) in PSMs as in PSCs. This strategy highlights the potential of NEP as a ligand solvent choice for the commercialization of PSCs. [ABSTRACT FROM AUTHOR]

N‐Methyl‐2‐pyrrolidone (NMP) has become one of the mainstream Lewis base ligand solvents for the fabrication of high‐quality FA‐based perovskite films. However, the NMP‐based perovskite films with small grain sizes always own a mirror surface which will increase the reflection of light and limit the current of perovskite solar cells (PSCs). In this work, 2‐pyrrolidone (NP) with a higher boiling point and stronger binding to precursor components is introduced into the precursor solution to improve the crystallization and morphology of perovskite. Finally, a rougher perovskite film with a larger grain size can be fabricated via an optimized NP and NMP mixed ligand solvent. Based on this strategy, the champion device achieved a power conversion efficiency (PCE) of 24.20% (certified PCE of 23.81%) and 22.13% on an aperture area of 0.0875 and 22.96 cm2, respectively. In addition, the introduction of NP enhances the humidity and light stability of the film, and the device retained 94.1% of its initial efficiency after 120 h. [ABSTRACT FROM AUTHOR]

Lightweight artificial muscles with large strain and large stress output have great application prospects in robotics, rehabilitation, prosthetic, and exoskeletons. Despite the excellent performance of carbon nanotube‐based artificial muscles in recent years, their widespread use is hindered by the high manufacturing costs associated with carbon nanotubes. In this paper, the study introduces a novel approach by developing artificial muscles based on pure conductive polymer coiled yarns. This achievement is facilitated by the successful fabrication of high‐strength conductive polymer microfibers. Furthermore, the study elucidates the molecular structural changes occurring during electrochemical processes that induce a substantial radial volume expansion in the microfibers. The resultant anisotropic volume change is magnified by the coiled yarn, yielding a remarkable contractile strain exceeding 11% at a high stress of 5 MPa, equivalent to lifting loads more than 4000 times their own masses, all achieved with a low input voltage of 1 V. Additionally, these conductive polymer‐based artificial muscles exhibit hydration‐induced contraction up to 33%, with swift recovery through electrical heating, leveraging their intrinsic high conductivity. This breakthrough positions high‐performance conductive polymer microfibers as a promising cost‐effective alternative to carbon nanotubes, establishing them at the forefront of lightweight artificial muscles. [ABSTRACT FROM AUTHOR]

The pick-up and transfer of easily deformable multi-layer fabrics is a challenge in the automation process of the textile industry. A transfer manipulator using interfacial adhesion forces has potential applications in the pick-up and transfer of fabrics. However, rapid adhesion and detachment cannot be achieved because of the small variability of adhesion and detachment forces between the fabric and the adhering material, which results in difficulty of picking and placing of fabric. To address this problem, in this study, an innovative pressure and strip manipulator structure is designed, utilizing the fabric gesture presented during the fabric peeling process to adjust the peel angle, and thereafter affect the adhesion force. The factors affecting the adhesion force, such as peeling speed, duration, and preload are analyzed, and a control method to regulate the adhesion force by peeling speed and the gap between the adhesion element and positioning block is proposed. Based on the interface adhesion force, the transfer manipulator can realize low-cost, high-stability, and high-efficiency fabric picking, which has good prospects for application in fabric production. [ABSTRACT FROM AUTHOR]

Tin‐based perovskite is a competitive analog with lead halide perovskite, but there are significant gaps in power conversion efficiency (PCE) and stability between tin‐ and lead‐based perovskite solar cells. The characteristics of the easy oxidizability of Sn2+ and the rapid crystal growth for tin‐based perovskite are two major issues remained to be overcome. Herein, an additive (4‐pyridylamidoxime (4‐PyAO)) with multiple functional groups is introduced in the perovskite precursor solution. The oxidation of Sn2+ and the crystallization rate of perovskite are both retarded by 4‐PyAO addition. The prepared perovskite film is of high quality with fewer trap states and carrier recombination, and carrier extraction and transfer between the perovskite film and the adjacent carrier transport layer also become more efficient. As a result, the corresponding devices deliver the highest PCE of 9.02%, accompanied by short‐circuit current density, open‐circuit voltage, and fill factor of 19.90 mA cm−2, 0.63 V, and 72.48%, respectively. More importantly, the best device without encapsulation maintains 92% of its initial PCE after 2500 h aging test in nitrogen atmosphere, which may be attributed to a synergic effect among the different functional groups. [ABSTRACT FROM AUTHOR]

The most crucial initial step in the metallization process of electroplating is the local contact openings in dielectric layers. In this article, an ultraviolet picosecond laser (UV‐ps), is used to open the front and back dielectric layer of the precursor of n‐TOPCon solar cells. By changing the laser parameters and spot overlap rate, the surface morphology of laser etching under different conditions is obtained and characterized by optical microscope and scanning electron microscope. The results indicate that there are three separate laser shock zones in the dielectric layer under the action of Gaussian light spot, and the corresponding ablation mechanisms are proposed. The longitudinal distribution of B element is characterized by secondary ion mass spectrometry to explore the effect of laser on its pn junction. In addition, the electrical characterization of lifetime photoluminescence is measured and calibrated using WCT120, and this indicates that the majority of the amorphous silicon is recrystallized when applying a fast firing oven process, and this hence improve the minority carrier lifetime and implied open‐circuit voltage. The laser damage to the emitter at the laser‐ablated regions is investigated using the emitter saturation current density, J0laser extracted by WCT120. [ABSTRACT FROM AUTHOR]

The creation of hierarchical nanostructures can effectively strengthen phonon scattering to reduce lattice thermal conductivity for improving thermoelectric properties in inorganic solids. Here, we use Zn doping to induce a remarkable reduction in the lattice thermal conductivity in SnTe, approaching the theoretical minimum limit. Microstructure analysis reveals that ZnTe nanoprecipitates can embed within SnTe grains beyond the solubility limit of Zn in the Zn alloyed SnTe. These nanoprecipitates result in a substantial decrease of the lattice thermal conductivity in SnTe, leading to an ultralow lattice thermal conductivity of 0.50 W m−1 K−1 at 773 K and a peak ZT of ~0.48 at 773 K, marking an approximately 45 % enhancement compared to pristine SnTe. This study underscores the effectiveness of incorporating ZnTe nanoprecipitates in boosting the thermoelectric performance of SnTe‐based materials. [ABSTRACT FROM AUTHOR]

In this work, stearic acid (SA) was used to improve the dispersion and tribological performance of graphene oxide (GO). The results exhibited that the SA could improve the dispersion of GO in water by the typical steric hindrance effect. As water-based lubricating additives, the GO modified by SA showed good tribological performance and load-carrying capacity, which had a low coefficient of friction and no obvious wear scar even sliding under the load of 400 mN for 2 h, indicating a long lubricating life. These superior performances were ascribed to the good dispersion of SA-modified GO in water and the synergistic effect of the excellent anti-wear property of GO and the good lubricating performance of SA. [ABSTRACT FROM AUTHOR]

The photovoltaic conversion efficiency of Sb2(S,Se)3 thin-film cells is significantly limited by carrier recombination at the back-contact interface. Therefore, an increasing number of studies have focused on back-contact interface optimisation. This study enhances the photovoltaic conversion efficiency of Sb2(S,Se)3 thin-film solar cells by utilizing NiOx as the hole transport layer (HTL). The inclusion of NiOx helps address the mismatch between the energy-level alignment of Sb2(S,Se)3 and the metal electrode, resulting in increased carrier collection efficiency and reduced carrier recombination at the back-contact interface, thus enhancing the performance of solar cells as a result. Under the same conditions, the NiOx film has a more suitable energy-level alignment with the Sb2(S,Se)3 film than the device fabricated with spiro-OMeTAD as the HTL, as it can extract and transport holes more efficiently and block electron transport. In addition, the influence of solution concentration and the annealing temperature on the NiOx film and device has undergone extensive investigation. The final NiOx device achieved a photovoltaic conversion efficiency of 7.40% and maintained an initial efficiency of 92% after 700 h, showing higher stability than the spiro-OMeTAD device. These findings show the enormous potential of NiOx as a hole-transport layer and offer fresh perspectives on choosing hole-transport layers for Sb2(S,Se)3 thin-film cells. [ABSTRACT FROM AUTHOR]

Ultra‐thin stainless‐steel substrates with excellent water‐oxygen barrier properties and high thermal and electrical conductivities are suitable for the fabrication of lightweight and flexible perovskite solar cells (FPSCs). However, the deposition of dense perovskite films on stainless steel by the solution method is crucial because short circuits caused by perovskite holes are fatal to parallel structures. Herein, a single crystal (SC) is incorporated into the precursor solution to reduce the formation of holes in perovskite films on smooth stainless‐steel substrates. Additionally, a magnetic method is developed based on the properties of stainless steel to fix and fabricate FPSCs nondestructively on ultra‐thin stainless‐steel films with a thickness as low as 5 μm. Furthermore, 4,6‐dimethyl‐2‐mercaptopyrimidine (DMI) was introduced to passivate the surface of the perovskite film, optimizing the contact properties of the perovskite heterojunction and adjusting the energy level of the perovskite/C60 interface. Finally, ultra‐thin FPSCs achieved a champion power conversion efficiency (PCE) of 20.24% on an active area of 1.012 cm2 and a power‐to‐weight ratio over 3000 W kg−1. Moreover, under continuous illumination, the stainless‐steel substrates exhibited better photothermal stability than the polymer substrates. This method provides a basis for the fabrication of lightweight, low‐cost, and large‐area FPSCs. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (NCs), such as MAPbX3 (MA+ = methylammonium; X = Cl, Br, or I), have received attention owing to their excellent optoelectronic properties and ease of integrating with flexible substrates. Lanthanide ion doping is widely used as an effective strategy to enhance the optoelectronic performance of perovskite NCs. However, incorporating the lanthanide dopant and ensuring the emission stability of the perovskite NCs in high‐performance optoelectronic devices remains a major challenge. Herein, the synthesis of Eu2+‐doped MAPbBr3 NCs within the channels of SBA‐15 is presented to improve their stability. The doped MAPbBr3 NC@SBA‐15 composites exhibit significantly improved stability than that of undoped MAPbBr3 NCs. The doped MAPbBr3 NC@SBA‐15 composites exhibit moderate PL quantum yields and excellent stability under ambient conditions and UV irradiation. In addition, the MAEu0.3Pb0.7Br3 NC@SBA‐15 composite applied in white‐light‐emitting diodes (WLEDs) achieves a color rendering index of 73.5. Moreover, MAEu0.3Pb0.7Br3 NC@SBA‐15 can be combined with styrene‐ethylene‐butylene‐styrene to fabricate a flexible direct X‐ray detector, realizing a high sensitivity of 7592.2 µC Gyair−1 cm−2 and a low detection limit of <77 nGyair s−1; this is an outstanding value for a NC‐based flexible direct X‐ray detector. This work serves as a guide for the design of perovskite NCs for both WLEDs and flexible X‐ray detectors. [ABSTRACT FROM AUTHOR]

Three-electronic-dimensional (3D) lead halide perovskites show high X-ray sensitivities and a low limit of detection. However, servere ion migration causes dark current drift and worsens long-term operational stability. Although two-electronic-dimensional (2D) perovskite and 3D perovskite heterojunction devices have been shown to reduce ion migration, their current responses to X-rays have decreased considerably. A device with low ion migration without sacrificing X-ray sensitivity is needed. Atomic-thick two-dimensional (2D) materials with small pore sizes between atoms and high carrier-tunneling possibilities through them are reasonable candidates to simultaneously block ion migration and retain carrier–transport properties. Herein, a 2D monolayer of g-C3N4 was introduced into a CH3NH3PbI3 (MAPbI3) polycrystalline pellet through hot pressing. The small-sized tri-s-triazine structure of g-C3N4 could inhibit ion migration without affecting the electron transport of the perovskite pellet. As a result, the g-C3N4/MAPbI3 heterojunction pellet exhibited an ultra-low current drift of 4.87 × 10−5 nA cm−1 s−1 V−1 at an electric field of 12.66 V mm−1. Simultaneously, the detector exhibited a high sensitivity of 1.78 × 105 μC Gyair−1 cm−2 under 75.95 V mm−1 and a low limit of detection of 27 nGyair s−1 under 12.66 V mm−1, which are among the best of reported results. This work provides an effective design strategy to develop X-ray detectors with low ion migration and high detection performance. [ABSTRACT FROM AUTHOR]

Reducing the interfacial defects between the perovskite/electron transport layer (ETL) is the key point to improving the efficient and stable performance of perovskite solar cells (PSCs). In this study, two self-assembled molecules ((aminomethyl)phosphonic acid and glycine) with different functional groups (phosphonic acid (-H2PO3) and carboxylic acid (-COOH)) were mixed to form the buried bottom interface of PSCs. The synergistic effect of -H2PO3 with its higher anchoring ability and -COOH with its fast carrier transport improved the performance of PSCs. Additionally, the SnO2 modified by mixed self-assembly molecules (M-SAM) showed a more appropriate energy level alignment, favoring charge transport and minimizing energy loss. In addition, the amine group (-NH2) on the two small molecules effectively interacted with uncoordinated Pb2+ in perovskite and improved the quality of the perovskite films. Consequently, the (FAPbI3)0.992(MAPbBr3)0.008 PSCs with M-SAM reached a PCE of 24.69% (0.08 cm2) and the perovskite modules achieved a champion efficiency of 18.57% (12.25 cm2 aperture area). Meanwhile, it still maintained more than 91% of its initial PCE after being placed in nitrogen atmosphere at 25 °C for 1500 h, which is better than that of the single-SAM and control devices. Further reference is provided for the future commercialization of perovskite with efficient and stable characteristics. [ABSTRACT FROM AUTHOR]

All‐inorganic perovskite solar cells (PSCs) have been the research focus due to their high thermal stability and proper band gap for tandem solar cells. However, their power conversion efficiency (PCE) is still lower than that of organic‐inorganic hybrid PSCs. Herein, a sacrificing dye (Rhodamine B isothiocyanate, RBITC) is developed to regulate the growth of perovskite film by in situ release of ethylammonium cations, isothiocyanate anions and benzoic acid molecules upon annealing and illumination. The ethylammonium cations can efficiently passivate surface defects. The isothiocyanate anions incorporate with uncoordinated Pb to regulate the crystallization process. The benzoic acid molecules facilitate the nucleation of the perovskite crystals. Especially, the illumination can accelerate the release of these beneficial ions/molecules to improve the quality of perovskite films further. After optimization with RBITC, a high open circuit voltage (VOC) of 1.24 V and a champion PCE of 20.95% are obtained, which are among the highest Voc and PCE values of CsPbI3 PSCs. Accordingly, the operational stability of the PSC devices is significantly improved. The results provide an efficient chemical strategy to regulate the formation of perovskite films in whole crystallization process for high performance all‐inorganic PSCs. [ABSTRACT FROM AUTHOR]

The efficiency of antimony selenide (Sb2Se3) solar cells is still limited by significant interface and deep‐level defects, in addition to carrier recombination at the back contact surface. This paper investigates the use of lithium (Li) ions as dopant for Sb2Se3 films, using lithium hydroxide (LiOH) as a dopant medium. Surprisingly, the LiOH solution not only reacts at the back surface of the Sb2Se3 film but also penetrate inside the film along the (Sb4Se6)n molecular chain. First, the Li ions modify the grain boundary's carrier type and create an electric field between p‐type grain interiors and n‐type grain boundary. Second, a gradient band structure is formed along the vertical direction with the diffusion of Li ions. Third, carrier collection and transport are improved at the surface between Sb2Se3 and the Au layer due to the reaction between the film and alkaline solution. Additionally, the diffusion of Li ions increases the crystallinity, orientation, surface evenness, and optical electricity. Ultimately, the efficiency of Sb2Se3 solar cells is improved to 7.57% due to the enhanced carrier extraction, transport, and collection, as well as the reduction of carrier recombination and deep defect density. This efficiency is also a record for CdS/Sb2Se3 solar cells fabricated by rapid thermal evaporation. [ABSTRACT FROM AUTHOR]

Antimony selenosulphide (Sb2(S,Se)3) has undergone rapid development recently owing to its adjustable band gap, high light-absorption coefficient and excellent optoelectronic properties as well as its safety, non-toxicity and low-cost aspects. High-efficiency Sb2(S,Se)3 thin film solar cells use Spiro-OMeTAD hollow-hole transport materials to construct n–i–p (n-type, intrinsic and p-type) structures; however, the poor stability and high cost of Spiro-OMeTAD limit its large-scale application in Sb2(S,Se)3 solar cells. Herein, in order to address these problems, we report stable and efficient Sb2(S,Se)3 solar cells enabled by various phthalocyanine hole transport layers (HTLs). The pure Pc and Sb2(S,Se)3 absorbers exhibited improved valence band alignment compared to Spiro-OMeTAD. The device with the tuning concentration of phthalocyanine solution shows high homogeneity and carrier transport. The increased hole transport capability of the Pc material facilitated a higher JSC in the Pc device, resulting in a photoelectric conversion efficiency of 8.42%. Furthermore, the Pc device maintained an initial efficiency of 97.5% after 700 h compared to the Spiro-OMeTAD-based device. These results demonstrate the great potential of the Pc hole transport layer and provide new insights into the selection of HTL materials for the preparation of highly efficient Sb2(S,Se)3 thin film solar cells. [ABSTRACT FROM AUTHOR]

P‐type NiOx films are widely used as hole‐transport layers (HTLs) in p–i–n perovskite solar cells (PSCs) owing to their wide bandgap, stability, and optical transmittance. Chemical bath deposition (CBD) is an effective method for growing metal oxide HTLs. However, NiOx films prepared by the CBD method have pinholes because of their small grain size, which makes it difficult to cover the substrate in all directions, leading to severe carrier recombination at the interface between NiOx and perovskite. Herein, the device efficiency is improved from 18.13% to 22.51% using NiOx prepared by CBD with seed‐assisted growth and Cu‐ion doping as the HTL. The addition of crystal seeds significantly enhances the grain size, resulting in better substrate coverage by the prepared NiOx films. Cu‐ion doping improves the conductivity of the film and enhances its ability to extract holes. In addition, the results confirm that this method is suitable for the manufacturing of large‐area modules and has good reproducibility. This research demonstrates an effective CBD method for creating NiOx films for use in PSCs and offers a new approach for preparing inorganic HTLs using CBD. [ABSTRACT FROM AUTHOR]

Uniform and pinhole‐free functional layers are essential for high‐efficient flexible perovskite solar modules (FPSMs). However, the poor wettability of self‐assembled monolayers (SAMs) with carbazole bodies and phosphonic acid binding groups usually leads to porous large‐area perovskite films. Herein, a layer of nickel oxide nanoparticles is inserted between sputtered nickel oxide and the SAM to increase the surface energy, and thus simultaneously improving the wettability and nucleation of the perovskite during vacuum‐quenching method. Following this strategy, the best flexible perovskite solar cells with an active area of 0.09 cm2 achieve a power conversion efficiency (PCE) of 21.97% under 1 sun illumination. In addition, FPSMs with the same structure exhibit a high fill factor approach 80% and reach a champion PCE of 19.71% on 58.14 cm2 active area and a certified PCE of 18.17% on 61.26 cm2 aperture area, which is the highest recorded PCE to the best knowledge. Furthermore, the optimized interface also enhances the adhesion between hole‐transport layer and perovskite, and the encapsulated device retains 95% of its initial PCE after 1000 cycles under a 2 cm bending radius. [ABSTRACT FROM AUTHOR]

The design of additives mainly involves selection of functional groups with coordination relationships with defects in perovskite materials. However, it is particularly important to further adjust the geometrical configuration and electronic structure of an additive. Here, the nicotinamide (NA) and its derivative 6‐Methylnicotinamide (CNA) with electron‐donor functional groups are comparatively analyzed to investigate the effect of molecular dipole and electronic configuration on the defect passivation of perovskite absorbers and the photovoltaic properties of perovskite solar cells (PSCs). Theoretical calculations demonstrate that the CNA molecule with its large molecular dipole combine with the undercoordinated Pb2+ ions in perovskite to form a higher binding energy, which is beneficial to improve the formation energy of Pb‐related defects. Experimental characterization confirms that the CNA molecule significantly enhances the coordination effect between acylamino and undercoordinated defective Pb2+ cations, which is conducive to obtain high‐quality, low‐defect density of state, large grain size, and smooth surface perovskite absorbers. Thanks to the electronic configuration and electronic cloud distribution of CNA molecules, the PSCs yield impressive efficiency as high as 24.33% with excellent environmental storage, heat, and light stabilities. This research provides a research basis for designing additives with steric‐charge‐dependence to assist perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

The 3D variable–stiffness structure can realize shape programming, reconstruction, adaptation, and locking, and therefore, it has a wide design creation space. Accurate local stiffness control is of considerable significance to the design and application of 3D variable–stiffness structures although it is challenging. Herein, a 3D variable–stiffness structure realization scheme based on a patterned heating network is introduced. The laser‐engraving and 3D‐printing technologies are combined to obtain a 3D variable–stiffness structure composed of a patterned graphene‐heating network (PGHN) and polylactic acid (PLA). The proposed scheme uses PGHN to accurately control the local stiffness of 3D PLA and realize programmable design and fabrication of 3D variable–stiffness structures. The "torsional structure," "hexagonal structure," and "spring" cases are used to elaborate the designability, excellent deformation and reconstruction capacity, and reasonable load bearing capacity of the PGHN/PLA variable–stiffness structure. A pneumatic disc, which is used as a reference for studies on shape control of PGHN/PLA variable–stiffness structures, is designed. Also, a pneumatic robot is designed based on the local stiffness control and shape‐locking function of PGHN/PLA to achieve multimode motion control using a single air source. The PGHN/PLA variable–stiffness structure has potential applications in multimode robots, wearable devices, and deployable structures. [ABSTRACT FROM AUTHOR]

Conductive hydrogels are widely used in biosensors, human–machine interfaces, and health recording electrodes. In this study, acrylamide and gelatin were introduced into the hydrogel. A conductive double-network hydrogel with high mechanical properties was prepared using the photoinduced one-pot method. The thermally reversible physical crosslinked gelatin constructed the first network, and the covalently crosslinked polyacrylamide formed the second one. The double networks increased the cross-linking strength between hydrogels; however, they dissipated energy and enhanced the mechanical properties. The addition of potassium chloride provided electrical conductivity for the hydrogels. The prepared double-network conductive hydrogel had high mechanical properties (tensile strength >800 KPa and tensile strain >1200%), good electrical conductivity (conductivity >0.9 S m−1), and excellent sensitivity (the gauge factor reached 1.88 when the strain was 400%). Moreover, a wide range of strain sensors was demonstrated based on gelatin/PAM DN hydrogels with high stability and durability, showing potential applications in wearable and fast response electronics. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) thin film solar cells were prepared by vapor transport deposition, and cesium chloride (CsCl2) solution was used to treat the upper interface of the device. Meanwhile, a series of characterizations of the thin film and the device were also performed. The study shows that the back contact treatment of CsCl2 solution can not only improve the carrier collection and reduce upper interface recombination of the device, but also optimize the crystallinity, surface roughness and optoelectronic performance of thin film. Based on the device structure of FTO/CdS/Sb2Se3/CsCl2/Au, a high-efficiency Sb2Se3 thin film solar cell with efficiency of 6.32% are obtained, which is 12% higher than that of the basic device. The research may provide some guidance to further development of Sb2 Se3 thin film solar cells and other similar types of semiconductor photovoltaic devices. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have become stars in photovoltaics due to their rapidly increased efficiency. However, their stability is still below par due to moisture permeation from grain boundaries and defects. To conquer both problems at once, a passivation agent 3,4,5,6‐tetrafluorophthalicacid (TFPA) is rationally designed to heal both for not only improved cell efficiency but also better stability. It is found that the TFPA is prone to distribute along grain boundaries and has little influence within the bulk of the perovskite film. In addition, it appears that the TFPA helps to reduce the film roughness, to adjust the energy level, to facilitate hole transporting from perovskite to spiro‐OMeTAD, and to increase the hydrophobicity of the perovskite film, as it is demonstrated by the inhibited nonradiative recombination and prolonged carrier lifetime. Owing to strong interactions between F, ‐COOH, and Pb, the device with TFPA shows outstanding efficiency and stability. A perovskite solar cell with TFPA modification delivers a champion efficiency of 23.70% and a significantly enhanced stability that the device maintains 90% of its initial efficiency after 5200 h, among the best ambient stability. Herein, an effective strategy of grain boundary passivation is provided to improve the stability of perovskite solar cells. [ABSTRACT FROM AUTHOR]

As the efficiency of perovskite solar cell has skyrocketed to as high as 25.7%, their stability has become the biggest obstacle to commercialization. Preliminary analyses suggest that additive engineering may be effective in improving both solar cell efficiency and its stability. Herein, the plant‐derived natural green additive of l‐Theanine (Thea) is selected to improve the crystal quality of the perovskite absorber and obtain high‐performance perovskite solar cells (PSCs) with ultraviolet/ozone (UV/O3) resistance. The characterization results reveal that the CO group in Thea can effectively inhibit the precipitation of metal Pb0, passivate undercoordinated Pb2+ ions, and promote the nucleation and crystallization of perovskite. In addition, the combination of the NH group and I− in the form of a hydrogen bond cooperatively reduce the probability of nonradiative recombination of photogenerated carriers and effectively improves the extraction ability of carriers from perovskite absorber. With the cooperation of CO and NH2 groups in Thea, the champion efficiency is improved from 22.29% in the control device to 24.58%. More importantly, Thea significantly alleviates the perovskite phase transition and film decomposition induced by UV/O3 treatment. The study provides exploratory research for the application of plant‐derived green additives in the UV/O3 resistance field of perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

Effectively encapsulating perovskite solar cells (PSCs) to enhance the external reliability is the key towards commercialization. We herein propose a facile encapsulation method by introducing conductive ribbons and a polyethylene terephthalate (PET) backsheet on both sides of PSC. Via applying thermoplastic polyolefin (TPO) encapsulant, we implemented PSCs with fine encapsulation, enabling considerable durability in the ambient atmosphere and even with water immersion, demonstrating almost no degradation in the device output, which is ascribed to the low water vapor transmission rate as well as the high chemical stability of TPO. The operation reliability of the encapsulated cell is also significantly increased, maintaining 80% of the initial efficiency after 770 hours' light illumination in an ambient atmosphere. This novel encapsulation route provides a feasible idea for the commercial application of PSCs in the future. [ABSTRACT FROM AUTHOR]

MXene film electrodes for supercapacitors, assembled with MXene nanosheets as structure units, inevitably suffer from self-restacking, which severely restrains ion transport kinetics and results in insufficient active site utilization and poor rate capability. Herein, an in situ foaming strategy employing the accumulated gas generated during the etching of sacrificial templates, combined with the confinement between the MXene film, has been proposed to fabricate pores between stacked MXene sheets and along the vertical direction of the film. The surface chemistry of the foamed film was further modified by alkali washing treatment to replace hydrophobic –F groups with hydrophilic –OH groups to improve electrolyte penetration and introduce more active sites. The resultant porous MXene film electrode exhibits a greatly improved specific capacitance (354.1 F g−1 at 5 mV s−1) and unparalleled rate capability (with a capacitance retention of 96.1% at 2000 mV s−1). This work demonstrates a facile but efficient method for the construction of porous MXene films, simultaneously providing insights into the promising applications of MXenes. [ABSTRACT FROM AUTHOR]

The additive strategy has emerged as an effective approach to improving the performance of perovskite solar cells (PSCs). Herein, a small acceptor-donor-acceptor type molecule indaceno[1,2-b:5,6-b′]dithiophene chloride (IDT-Cl) is designed and synthesized to advance both the efficiency and stability of FA0.85MA0.15PbI3 PSCs. Within the IDT-Cl molecule, the S-group with high electron density promotes chemical bonding with the lead cations in the perovskite, resulting in enlarged grain size and smoother surface topography of the perovskite absorber. In addition, the undercoordinated lead ions in the perovskite layer may be passivated by the carbonyl group in the 5-chloroindolin-2-one unit, thereby reducing the number of nonradiative recombination centers. Meanwhile, the IDT-Cl adjusts the energy level mismatch between the perovskite and two adjacent carrier transport layers, leading to easy charge collection. By the multifunctional effect of the IDT-Cl molecule, the modified device yields a high power conversion efficiency (PCE) of 24.46%, 8.8% higher than that of the control PSC (22.48%). More importantly, the hydrophobic alkyl side-chain of the IDT-Cl molecule further ensures enhanced humidity stability of the perovskite film and environmental, thermal, and light stabilities of the PSC devices. [ABSTRACT FROM AUTHOR]

Solar cell efficiency and stability are two key metrics to determine whether a photovoltaic device is viable for commercial applications. The surface termination of the perovskite layer plays a pivotal role in not only the photoelectric conversion efficiency (PCE) but also the stability of assembled perovskite solar cells (PSCs). Herein, a strong chelate coordination bond is designed to terminate the surface of the perovskite absorber layer. On the one hand, the ligand anions bind with Pb cations via a bidentate chelating bond to restrict the ion migration, and the chelate surface termination changes the surface from hydrophilic to hydrophobic. Both are beneficial to improving the long‐term stability. On the other hand, the formation of the chelating bonding effectively eliminates the deep‐level defects including PbI and Pb clusters on the Pb‐I and FA‐I terminations, respectively, as confirmed by theoretical simulation and experimental results. Consequently, the PCE is increased to 24.52%, open circuit voltage to 1.19 V, and fill factor to 81.53%; all three are among the highest for hybrid perovskite cells. The present strategy provides a straightforward means to enhance both the PCE and long‐term stability of PSCs. [ABSTRACT FROM AUTHOR]

The development of inorganic hole‐transporting materials (HTMs) is one of the most reliable ways to improve the stability of perovskite solar cells (PSCs). However, the un‐optimal buried interfacial contacts and the defects located at the inorganic HTMs/perovskite interface restricted the device's performance. Herein, a phase‐pure CuScO2 has been synthesized and further employed as mesoporous HTM in inverted PSCs. Surprisingly, a facile pretreatment of the hole‐transport layer by a formamidine salt compensates the I− vacancy of the buried perovskite film, thus regulating the interfacial band energy alignment between the HTM and perovskite. This ion compensation strategy can not only in situ repair the ion loss and improve the built‐in electric field, but also decrease the charge injection barrier and suppress the non‐radiative interfacial recombination. Benefiting from these merits, the resulting methylammonium‐free (MA), Cs/FA‐based PSCs displays a power conversion efficiency (PCE) of 22.42% along with excellent thermal and light stability. Moreover, the pre‐buried treatment strategy can be extended to MA‐containing CsFAMA triple‐cation perovskite film, and a champion inverted device delivers a PCE of 23.11%. This study offers a new avenue to the rational design of HTMs for highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbI3 perovskite presents preeminent chemical stability and a desirable band gap as the front absorber for perovskite/silicon tandem solar cells. Unfortunately, CsPbI3 perovskite solar cells (PSCs) still show low efficiency due to high density of defects in solution‐prepared CsPbI3 films. Herein, three kinds of hydrazide derivatives (benzoyl hydrazine (BH), formohydrazide (FH) and benzamide (BA)) are designed to reduce the defect density and stabilize the phase of CsPbI3. Calculation and characterization results corroborate that the carboxyl and hydrazine groups in BH form strong chemical bonds with Pb2+ ions, resulting in synergetic double coordination. In addition, the hydrazine group in the BH also forms a hydrogen bond with iodine to assist the coordination. Consequently, a high efficiency of 20.47 % is achieved, which is the highest PCE among all pure CsPbI3‐based PSCs reported to date. In addition, an unencapsulated device showed excellent stability in ambient air. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbI3 perovskite presents preeminent chemical stability and a desirable band gap as the front absorber for perovskite/silicon tandem solar cells. Unfortunately, CsPbI3 perovskite solar cells (PSCs) still show low efficiency due to high density of defects in solution‐prepared CsPbI3 films. Herein, three kinds of hydrazide derivatives (benzoyl hydrazine (BH), formohydrazide (FH) and benzamide (BA)) are designed to reduce the defect density and stabilize the phase of CsPbI3. Calculation and characterization results corroborate that the carboxyl and hydrazine groups in BH form strong chemical bonds with Pb2+ ions, resulting in synergetic double coordination. In addition, the hydrazine group in the BH also forms a hydrogen bond with iodine to assist the coordination. Consequently, a high efficiency of 20.47 % is achieved, which is the highest PCE among all pure CsPbI3‐based PSCs reported to date. In addition, an unencapsulated device showed excellent stability in ambient air. [ABSTRACT FROM AUTHOR]

CsPbI2Br perovskite is known for its advantages over its organic‐inorganic hybrid counterpart including better thermal stability and appropriate bandgap for the front sub‐cell of tandem solar cell. However, its lower‐than‐satisfactory efficiency, problematic phase stability and sensitivity to moisture hinder its further advancement. Here, three kinds of glycine halides (Gly‐X: X = Cl, Br, and I) are strategically deigned to improve the performance of CsPbI2Br perovskite solar cells (PSCs). Systematic experimental and calculated results prove that a 2D/3D hybrid structure is formed, wherein the Gly‐X‐based 2D perovskite is mainly located at the CsPbI2Br grain boundaries, and the A‐sites of the 2D perovskite form strong bonds with the 3D perovskite to suppress ion migration by increasing its activation energy. As a result, a power conversion efficiency (PCE) of 17.26% was obtained with an open‐circuit voltage (VOC) of 1.33 V, which is among the best PCE values for the CsPbI2Br PSCs. In addition, the efficiency of encapsulated device decrease only by 14.1% after 340 h continuous illumination in ambient conditions, representing one of the most‐stable inorganic PSCs reported so far. This work provides important insights into designing passivating agents to address the issue of phase segregation for the development of highly stable perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

The additive strategy is considered to be an effective scheme to purposefully passivate defect sites in perovskite materials. Herein, a small molecule trifluoroacetamide (TFAA) with C═O, −NH2, and F groups is incorporated into the perovskite precursor solution to alleviate the defect densities of the perovskite material from the source, so as to obtain high‐quality FA0.85MA0.15PbI3 perovskite absorber and its assembled photovoltaic devices. Thanks to the interactions of Lewis acid of C═O and undercoordinated Pb2+, N—H and I− via hydrogen bond, and F and FA+ fragments, the nonradiative recombination sites are effectively inhibited, simultaneously promoting the nucleation and grain growth of perovskite. The analysis results demonstrate that the introduction of TFAA additive greatly enhances the crystal quality of bulk perovskite absorber, ameliorates the surface morphology of perovskite film, and improves the extraction and transfer abilities of photogenerated carriers from perovskite absorber. The perovskite solar cells (PSCs) based on TFAA agent yield a champion power conversion efficiency of 24.16%, 8.3% better than that of the control device (22.31%). More importantly, the modified perovskite film has good harsh humidity stability and the unpackaged PSCs maintain outstanding photovoltaic performance in atmospheric environment, thermal, and light conditions. [ABSTRACT FROM AUTHOR]

Formamidinium methylammonium lead iodide (FAMAPbI3) perovskite has been intensively investigated as a potential photovoltaic material because it has higher phase stability than its pure FAPbI3 perovskite counterpart. However, its power conversion efficiency (PCE) is significantly inferior due to its high density of surface detects and mismatched energy level with electrodes. Herein, a bifunctional passivator, methyl haloacetate (methyl chloroacetate, (MClA), methyl bromoacetate (MBrA)), is designed to reduce defect density, to tune the energy levels and to improve interfacial charge extraction in the FAMAPbI3 perovskite cell by synergistic passivation of both CO groups and halogen anions. As predicted by modeling undercoordinated Pb2+, the MBrA shows a very strong interaction with Pb2+ by forming a dimer complex ([C6H10Br2O4Pb]2+), which effectively reduces the defect density of the perovskite and suppresses non‐radiative recombination. Meanwhile, the Br− in MBrA passivates iodine‐deficient defects. Consequently, the MBrA‐modified device presents an excellent PCE of 24.29%, an open‐circuit voltage (Voc) of 1.18 V (Voc loss ≈ 0.38 V), which is one of the highest PCEs among all FAMAPbI3‐based perovskite solar cells reported to date. Furthermore, the MBrA‐modified devices without any encapsulation exhibit remarkable long‐term stability with only 9% of PCE loss after exposure to ambient air for 1440 h. [ABSTRACT FROM AUTHOR]