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The improvement of photovoltaic and stability performance of tin (Sn)‐based halide perovskite solar cells is impeded by notorious oxidation issues and Anderson localization. Despite previous implements in antioxidation through the incorporation of Lewis base additives, there still exist ongoing uncertainties surrounding its complex interaction mechanisms. A perplexing phenomenon regarding accelerated oxidation in acrylic acid is discovered that deviates from conventional Lewis base–acid reaction. The underlying insights into the deprotonation of acrylic acid followed by the formation of a "tripod" ionic bonding form are provided, which results in amplifying the delocalization effect of electrons of Sn2+. Furthermore, with the assistance of acrylamide and acrolein, synergistic enhancement in terms of the antioxidation and suppression of Anderson localization can be achieved — a concept referred to as "Dual Synergistic Engineering". This suppresses the oxidation of Sn2+ and reduces Sn4+ content by ≈76%. Meanwhile, the diffusion length is prolonged significantly from 195.9 to 458.9 nm. The optimized all‐inorganic Sn/Pb‐based perovskite solar cells exhibit a power conversion efficiency of above 14% with enhanced stability. These findings provide an alternative viewpoint for comprehending the impact of chemical interaction on oxidation and crystal growth in Sn/Pb‐based perovskites. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have seen remarkable progress in recent years, largely attributed to various additives that enhance both efficiency and stability. Among these, fluorine-containing additives have garnered significant interest because of their unique hydrophobic properties, effective defect passivation, and regulation capability on the crystallization process. However, a targeted structural approach to design such additives is necessary to further enhance the performance of PSCs. Here, fluoroalkyl ethylene with different fluoroalkyl chain lengths (CH2CH(CF2)nCF3, n = 3, 5, and 7) as liquid additives is used to investigate influences of fluoroalkyl chain lengths on crystallization regulation and defect passivation. The findings indicate that optimizing the quantity of F groups plays a crucial role in regulating the electron cloud distribution within the additive molecules. This optimization fosters strong hydrogen bonds and coordination effects with FA+ and uncoordinated Pb2+, ultimately enhancing crystal quality and device performance. Notably, 1H,1H,2H-perfluoro-1-hexene (PF3) with the optimal number of F presents the most effective modulation effect. A PSC utilizing PF3 achieves an efficiency of 24.05%, and exhibits exceptional stability against humidity and thermal fluctuations. This work sheds light on the importance of tailored structure designs in additives for achieving high-performance PSCs. [ABSTRACT FROM AUTHOR]

In situ cyclized polyacrylonitrile (CPAN) is developed to replace n‐type metal oxide semiconductors (TiO2 or SnO2) as an electron selective layer (ESL) for highly efficient and stable n‐i‐p perovskite solar cells (PSCs). The CPAN layer is fabricated via facile in situ cyclization reaction of polyacrylonitrile (PAN) coated on a conducting glass substrate. The CPAN layer is robust and insoluble in common solvents, and possesses n‐type semiconductor properties with a high electron mobility of 4.13×10−3 cm2 V−1 s−1. With the CPAN as an ESL, the PSC affords a power conversion efficiency (PCE) of 23.12 %, which is the highest for the n‐i‐p PSCs with organic ESLs. Moreover, the device with the CPAN layer holds superior operational stability, maintaining over 90 % of their initial efficiency after 500 h continuous light soaking. These results confirm that the CPAN layer would be a desirable low‐cost and efficient ESL for n‐i‐p PSCs and other photoelectronic devices with high performance and stability. [ABSTRACT FROM AUTHOR]

Well‐engineered buried interfaces play a pivotal role in achieving high‐performance perovskite solar cells (PSCs). A superior buried interface involves controlled perovskite crystallization, efficient charge transfer across interfaces, and robust interfacial bonding. Here, a class of innovative additives, benzoyl sulfonyl molecules including 4‐sulfobenzoic acid monopotassium salt (K‐SBA), and 4‐sulfamoylbenzoic acid (SBA) is introduced to tailer the SnO2/perovskite buried interface, aiming to meet these essential criteria. Among them, K‐SBA performed better. The findings reveal that the functional groups of K‐SBA establish interactions with both SnO2 and perovskite, leading to effective bilateral passivation and mitigation of interface stress. This results in the formation of a pore‐free buried interface and high‐quality perovskite films with substantial crystal sizes. Consequently, PSCs incorporating K‐SBA exhibited a notable increase in efficiency, achieving 24.56% efficiency compared to the control device's 22.27%. Furthermore, these K‐SBA‐enhanced PSCs maintain 90% of their original efficiency even after 500 h of maximum power point tracking. This work provides valuable insights for further refinement and advancement of buried interfaces in PSCs. [ABSTRACT FROM AUTHOR]

Metal-halide perovskite solar cells have garnered significant research attention in the last decade due to their exceptional photovoltaic performance and potential for commercialization. Despite achieving remarkable power conversion efficiency of up to 26.1%, a substantial discrepancy persists when compared to the theoretical Shockley–Queisser (SQ) limit. One of the most serious challenges facing perovskite solar cells is the energy loss incurred during photovoltaic conversion, which affects the SQ limits and stability of the device. More significant than the energy loss occurring in the bulk phase of the perovskite is the energy loss occurring at the surface-interface. Here, we provide a systematic overview of the physical and chemical properties of the surface-interface. Firstly, we delve into the underlying mechanism causing the energy deficit and structural degradation at the surface-interface, aiming to enhance the understanding of carrier transport processes and structural chemical reactivity. Furthermore, we systematically summarized the primary modulating pathways, including surface reconstruction, dimensional construction, and electric-field regulation. Finally, we propose directions for future research to advance the efficiency of perovskite solar cells towards the radiative limit and their widespread commercial application. [ABSTRACT FROM AUTHOR]

Low‐dimensional (LD) perovskite has provided an exciting avenue for exploring stable perovskite solar cells (PSCs). However, PSCs based on LD perovskites still suffer from poor efficiency owing to unfavorable charge carrier dynamics. Here, cystamine (CYS) is employed as a ligand to construct LD Dion‐Jacobson (LDDJ) perovskite (CYS)MAn‐1PbnI3n+1 (n = 1, 2, 3..., MA: methylamine) for improving carrier properties. The disulfide bond not only changes the polarization characteristic but also increases the coupling between inorganic slabs due to the low barrier of rotation around the S‐S axis, thus reducing the exciton binding energy of CYS‐based LDDJ perovskite. Disulfide bonds provide a scene for charge localization in the interlayer region, which is conducive to reducing the anisotropy of charge transfer. Thanks to these merits, the (CYS)MA4Pb5I16 film delivers improved carrier diffusion length (electron for 1345 nm and hole for 950 nm) and mobility (9.23 cm2 V−1 S−1). As a result, the (CYS)(MA)4Pb5I16 PSC achieves a champion power conversion efficiency (PCE) of 16.52%, which is much higher than that of HDA and BA cations‐based PSCs (HDA: 1,6‐Hexanediamine, BA: Butylamine). Furthermore, the state‐of‐the‐art device only lost 8% of its initial PCE after 1600 h in the atmosphere. [ABSTRACT FROM AUTHOR]

Despite the remarkable progress made in perovskite solar cells, great concerns regarding potential Pb contamination risk and environmental vulnerability risks associated with perovskite solar cells pose a significant obstacle to their real-world commercialization. In this study, we took inspiration from the ensnaring prey behavior of spiders and chemical components in spider web to strategically implant a multifunctional mesoporous amino-grafted-carbon net into perovskite solar cells, creating a biomimetic cage traps that could effectively mitigate Pb leakage and shield the external invasion under extreme weather conditions. The synergistic Pb capturing mechanism in terms of chemical chelation and physical adsorption is in-depth explored. Additionally, the Pb contamination assessment of end-of-life perovskite solar cells in the real-world ecosystem, including Yellow River water and soil, is proposed. The sustainable closed-loop Pb management process is also successfully established involving four critical steps: Pb precipitation, Pb adsorption, Pb desorption, and Pb recycling. Our findings provide inspiring insights for promoting green and sustainable industrialization of perovskite solar cells. Potential lead contamination risk and environmental vulnerability risk impose a significant obstacle for the commercialization of perovskite solar cells. Here, the authors create a biomimetic cage traps to mitigate lead leakage and establish a sustainable closed-loop lead management process. [ABSTRACT FROM AUTHOR]

The unprecedented development of perovskite solar cells (PSCs) makes them one of the most promising candidates for terawatt‐scale green energy production with low cost. However, the high boiling point solvents during the solution‐processed film deposition cause anisotropic crystal growth and toxic solvent vapor during high‐throughput manufacturing. Here, a dual‐component green solvent consisting of isopropyl acetate and acetonitrile is proposed to form a volatile perovskite precursor, which can realize the high‐quality perovskite thin film deposition by intermediate phase regulation. A room‐temperature stable perovskite intermediate phase is constructed with the engagement of isopropyl acetate as co‐solvent, which suppresses the exploding nucleation rate in volatile perovskite precursor, providing a fine grain growth rate and wide processing window in scalable film deposition. The corresponding PSCs fabricated by blade coating without anti‐solvents or gas quenching achieve power conversion efficiency (PCE) of 16.37 % and 15.29 % for the areas of 14.08 cm2 and 37.83 cm2, respectively. [ABSTRACT FROM AUTHOR]

The two‐step sequentially deposition strategy has been widely used to produce high‐performance FAPbI3‐based solar cells. However, due to the rapid reaction between PbI2 and FAI, a dense perovskite film forms on top of the PbI2 layer immediately and blocks the FAI diffusion into the bottom of the PbI2 film for a complete reaction, which results in a low‐efficiency and limited reproducibility of perovskite solar cells (PSCs). Here, high‐quality α‐FAPbI3 perovskite films by crystal growth regulation with 4‐fluorobenzamide additives is fabricated. The additives can interact with FAI to suppress the fast reaction between the FAI and PbI2 and effectively passivate the under‐coordinated Pb2+ or I‐ defects. As a result, α‐FAPbI3 perovskite films with low trap density and large grain size are prepared. The modified PSCs present a high‐power conversion efficiency of 24.08%, maintaining 90% of their initial efficiency after 1400 h in high humidity. This study provides an efficient strategy of synergistic crystallization and passivation to form high‐quality α‐FAPbI3 films for high‐performance PSCs. [ABSTRACT FROM AUTHOR]

Low‐dimensional Ruddlesden‐Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ‐aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA)2MA3Pb4I13 (MA=CH3NH3+), leading to the charges localized in the van der Waals gap, thereby constructing "charged‐bridge" for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA)2MA3Pb4I13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA‐based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h. [ABSTRACT FROM AUTHOR]

Advancing hole transport layers (HTL) to realize large‐area, flexible, and high‐performance perovskite solar cells (PSCs) is one of the most challenging issues for its commercialization. Here, a self‐assembled gradient Ti3C2Tx MXene incorporated PEDOT:PSS HTL is demonstrated to achieve high‐performance large‐area PSCs by establishing half‐caramelization‐based glucose‐induced MXene redistribution. Through this process, the Ti3C2Tx MXene nanosheets are spontaneously dispersed and redistributed at the top region of HTL to form the unique gradient distribution structure composed of MXene:Glucose:PEDOT:PSS (MG‐PEDOT). These results show that the MG‐PEDOT HTL not only offers favorable energy level alignment and efficient charge extraction, but also improves the film quality of perovskite layer featuring enlarged grain size, lower trap density, and longer carrier lifetime. Consequently, the power conversion efficiency (PCE) of the flexible device based on MG‐PEDOT HTL is increased by 36% compared to that of pristine PEDOT:PSS HTL. Meanwhile, the flexible perovskite solar minimodule (15 cm2 area) using MG‐PEDOT HTL achieve a PCE of 17.06%. The encapsulated modules show remarkable long‐term storage stability at 85 °C in ambient air (≈90% efficiency retention after 1200 h) and enhanced operational lifetime (≈90% efficiency retention after 200 h). This new approach shows a promising future of the self‐assembled HTLs for developing optoelectronic devices. [ABSTRACT FROM AUTHOR]

The solution process of perovskite solar cells may lead to widespread defects in the device, causing severe nonradiative recombination and the loss of conversion efficiency. Herein, a strategy of embedding thiourea into perovskite to manipulate the crystallization process and passivate the defects simultaneously is demonstrated. A competitive crystallization mechanism by embedding thiourea into perovskite has been proposed for the improvement of morphology and crystallinity. The defects in the device have been dramatically decreased by the strong coordination of CS bond in thiourea with the undercoordinated Pb2+. Moreover, the bilateral affinity of thiourea to the SnO2 and perovskite can enhance the interface contact by the bridging bonding, which will release the residual stress of perovskite films. As a result, the thiourea‐embedding device achieves a power conversion efficiency over 24% and shows excellent storage and illumination stabilities. Even undergoing 3768 h storage, the maximum efficiency value of unencapsulated device keeps over 94%. Furthermore, the efficiency of the optimized device maintains over 80% after 120 h continuous illumination at 60 °C. [ABSTRACT FROM AUTHOR]

Grain boundary cracks in flexible perovskite films can be repaired by filling with self‐repairing polymers during the preparation and wearable operation. However, the self‐repairing polymers are commonly active through external heating or humidification treatments, which cannot match with the human body's temperature tolerance of wearable devices. Herein, a body temperature‐responsive shape memory polyurethane (SMPU) is demonstrated to achieve the real‐time mechanical self‐repairing of grain boundary cracks (~37°C). Furthermore, the strong intermolecular interaction between SMPU and the uncoordinated Pb2+ and I−, can reduce the trap density in perovskite films. The blade‐coated device achieves a power conversion efficiency (PCE) of 21.33%, which is among the best reported flexible perovskite solar cells (PSCs; 0.10 cm2). Importantly, the device with SMPU can recover more than 80% of the PCE after 6000 cycles (bending radius: 8 mm). Finally, the flexible PSCs are used for wearable solar power supply of a smartphone, which show great potential for self‐repairing wearable electronics. [ABSTRACT FROM AUTHOR]

Defects at the interfaces of perovskite (PVK) thin films are the main factors responsible for instability and low photoelectric conversion efficiency (PCE) of PVK solar cells (PSCs). Here, a SnO2‐MXene composite electron transport layer (ETL) is used in PSCs to improve interfacial contact and passivate defects at the SnO2/perovskite interface. The introduced MXene regulates SnO2 dispersion and induces a vertical growth of PVK. The lattice matching of MXene and perovskite suppresses the concentration of interfacial stress, thereby obtaining a perovskite film with low defects. Compared with SnO2‐based device, the PCE of SnO2‐MXene‐based device is improved by 15 % and its short‐circuit current is up to 25.07 mA cm−2. Furthermore, unencapsulated device maintained about 90 % of its initial efficiency even after 500 h of storage at 30–40 % relative humidity in ambient air. The composite ETL strategy provides a route to engineer interfacial passivation between metal halide perovskites and ETLs. [ABSTRACT FROM AUTHOR]

Solution‐processed 2D perovskite films generally contain mixed quantum wells (QWs) with multiple well width distribution, which seriously weakens the charge transfer. To achieve regulation of the QW width, strategies to optimize the crystallization dynamics of 2D perovskite films are urgently needed. In this review, systematic summary on QW distribution and guidelines for 2D perovskite phase regulation is provided, aiming to establish a general manual for preparing efficient 2D perovskite solar cells (PSCs). The factors affecting the distribution of multiple‐QWs in 2D perovskite films, including component engineering, additive engineering, process optimization, are first generalized. Then an extensive review of these factors that are widely used to reconstruct 2D perovskite crystallization process is conducted. Leveraging these insights, the effect of QWs distributions on 2D PSCs properties is also summarized. Similarly, considering the crystallization kinetics and device performance, the QWs width control of 2D perovskite films from the aspects of ligand engineering, precursor design, and fabrication optimization, is rationalized. Finally, an outlook on how to realize ordered QWs distribution in perovskite films for efficient 2D PSCs is proposed. [ABSTRACT FROM AUTHOR]

Pb‐based perovskite solar cells (PSCs) as one of the most promising photovoltaic technologies for commercialization have attracted tremendous attention in recent years. However, the toxicity and leakage of heavy metal Pb from perovskite film have become critical obstacles for eco‐friendly development. Extreme weather conditions such as heavy rain, high temperature, or strong sunlight may accelerate the undesired decomposition of perovskite film and cause inevitable Pb contamination in the ecosystem, which results in a potential threat to animals and the environment. In this review, guidelines for successfully managing Pb in PSCs are provided to open a pathway toward sustainable development. First, the toxicological research of Pb that can cause health problems for humans and contaminate the environment is discussed. Then, the decomposition mechanism of perovskite film and Pb leakage pathways under simulated environments in terms of moisture, high temperature, and illumination are briefly reviewed. Moreover, strategies to inhibit Pb leakage including physical sequestration, chemical adsorption, and Pb component substitution engineering are systematically summarized. Finally, different pathways for achieving the goal of Pb recycling and sustainable utilization are systematically analyzed. With a comprehensive understanding of these effects, rational strategies for sustainable Pb management can be made to accelerate the development of this emerging field. [ABSTRACT FROM AUTHOR]

Inorganic cesium lead iodide perovskite CsPbI3 is attracting great attention as a light absorber for single or multi‐junction photovoltaics due to its outstanding thermal stability and proper band gap. However, the device performance of CsPbI3‐based perovskite solar cells (PSCs) is limited by the unsatisfactory crystal quality and thus severe non‐radiative recombination. Here, vacuum‐assisted thermal annealing (VATA) is demonstrated as an effective approach for controlling the morphology and crystallinity of the CsPbI3 perovskite films formed from the precursors of PbI2, CsI, and dimethylammonium iodide (DMAI). By this method, a large‐area and high‐quality CsPbI3 film is obtained, exhibiting a much reduced trap‐state density with prolonged charge lifetime. Consequently, the solar cell efficiency is raised from 17.26 to 20.06 %, along with enhanced stability. The VATA would be an effective approach for fabricating high‐performance thin‐film CsPbI3 perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

Metal halide perovskite, an emerging photosensitive semiconductor, has been widely employed in solar cells, light‐emitting diodes, photodetectors, and lasers owing to its excellent photophysical properties and simple solution preparation processing. However, as a photoactive layer, the higher refractive index and thinner thickness of perovskite film can cause reflection and transmission at the interface, and confine the emitted light within devices, resulting in the poor incident photon absorption and emitted photon extraction. In addition, the intrinsic brittleness of perovskite material restricts its potential applications in flexible optoelectronics. Therefore, great effort has been put into micro‐nano structured perovskite optoelectronics, and the reported reviews mainly focus on the fabrication process of micro‐nano patterned perovskite. Herein, the functionalities of micro‐nano structures in optoelectronics, including improving the light trapping, light extraction, light modulation, carrier dynamics, mechanical robustness, and other novel functionalities, are comprehensively reviewed. The specific applications of these functionalities in perovskite‐based optoelectronic devices are then discussed in detail to provide a better understanding of the photophysical properties of micro‐nano structure functionalized optoelectronics. Finally, promising strategies to promote the multifunctional commercial applications of micro‐nano structured perovskite optoelectronics are provided. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite solar cells (PSCs) have attracted great attentions due to their rapid increase of power conversion efficiency (PCE). Although the highest PCE of PSCs (25.7%) has been achieved via using formamidinium lead iodide (FAPbI3) with a suitable bandgap, there is still a lack of systematic analysis on FAPbI3‐based PSCs toward high stability and high efficiency. Herein, the progress in FAPbI3 films and achievements in their high‐efficiency and long‐term stability PSCs are comprehensively reviewed. First, the progress from the aspects of morphology, defect, dimension, and strain for FAPbI3 film optimization is summarized and then the development of FAPbI3 PSCs in both efficiency and stability is discussed. Then, the methods to improve the FAPbI3 film quality by morphology control, defect passivation, dimensional regulation, and strain engineering, as well as strategies to optimize the device structure and interface layers, which are critical to promote device stability and efficiency, are evaluated. Finally, the outlook and strategies for realizing commercialized FAPbI3 PSCs with high efficiency and long lifetime are discussed. [ABSTRACT FROM AUTHOR]

Formamidinium (FA) based perovskites are considered as one of the most promising light‐absorbing perovskite materials owing to their narrower band gap and better thermal stability compared to conventional methylammonium‐based perovskites. Constant improvement by using various additives stimulates the potential application of these perovskites. Amine molecules with different structures have been widely used as typical additives in FA‐based perovskite solar cells, and decent performances have been achieved. Thus, a systematic review focusing on structural regulation and functional construction of amines in FA‐based perovskites is of significance. Herein, we analyze the construction mechanism of different structural amines on the functional perovskite crystals. The influence of amine molecules on specific perovskite properties including defect conditions, charge transfer, and moisture resistance are evaluated. Finally, we summarize the design rules of amine molecules for the application in high‐performance FA‐based perovskites and propose directions for the future development of additive molecules. [ABSTRACT FROM AUTHOR]

3D tin-based halide perovskites are promising light absorbers for perovskite solar cells (PSCs) due to their non-toxicity, suitable optical band gaps, and excellent optoelectronic properties. However, the inherent rapid crystallization and easy oxidation of Sn2+ to Sn4+ in 3D perovskites result in a low power conversion efficiency (PCE) and poor stability of tin perovskite solar cells compared with the lead counterparts. In this report, quasi-2D hybrid tin-based perovskite films are fabricated by using 2-thiopheneethylammonium (TEA+) as the spacer cation in MASnI3 (MA: CH3NH3+), leading to the formation of quasi-2D perovskite films with high orientation and a low content of Sn4+. As a result, the perovskite solar cells show a considerable power-conversion efficiency of 6.8%, which is among the highest values reported for MASnI3-based solar cells. Moreover, the devices exhibited excellent stability compared with the device without TEAI. [ABSTRACT FROM AUTHOR]

Hybrid organic-inorganic perovskite solar cells have attracted considerable attention over the past decade, delivering high power conversion efficiencies over 25%. There still exist challenges regarding precisely regulating perovskite crystallization kinetics due to the random nucleation and disordered diffusion growth in the spontaneous solution chemical reaction process, subsequently leading to poor film quality with chaotic microstructure arrangement and undesired defect states which compromises the photovoltaic performance. Recently, the research priority in the perovskite photovoltaic community has put emphasis on seed templates driving controllable growth of perovskite film, triggering excitement for novel manufacturing technologies. Herein, we provide a systematic overview covering the current pioneering works to comprehend the advances of seed template regulation approaches and the underlying mechanism in terms of microstructure evolution and optoelectronic properties. The intense search regarding constructing representative perovskite single and polycrystalline crystals is provided to elaborate on the prominent roles of seed templates. [Display omitted] • In-depth theoretical mechanisms regarding heteroepitaxial growth and advanced regulation strategies are provided. • Conceptual insights into structural properties in perovskite polycrystals are proposed. • The promising progress regarding controlling over the perovskite single crystals growth is introduced. [ABSTRACT FROM AUTHOR]

Although outstanding power conversion efficiency (PCE) has been achieved in flexible perovskite solar cells, unsatisfactory operational stability and toxicity caused by the moisture transmittance of polymer packaging are still the bottleneck challenges that limit their applications. Herein, inspired by the non‐selective permeability of inactivated cell membrane, the diphosphatidyl‐glycerol (Di‐g) is tactfully introduced as a self‐shield interface upon the perovskite layer. 96% of lead leakage is suppressed because the amphipathic Di‐g can simultaneously bind tightly to the divalent lead ion and afford an interfacial water‐resistance. More importantly, the gradient distribution of lattice residual stress perpendicular to the substrate are optimized. The resultant flexible devices achieve a PCE of 20.29% and 15.01% at effective areas of 1.01 and 21.82 cm2 respectively, yielding excellent environmental and mechanical stability. This strategy exhibits the feasibility of developing interfacial encapsulation to stabilize scalable PSCs with negligible lead leakage. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are promising photovoltaic technologies due to their impressive power conversion efficiency (PCE) and low‐temperature fabrication process, while it is still challenging to print uniform perovskite film with high crystalline quality over a module size. Here, a printable and stable perovskite nanocapsules ink to realize the high‐throughput printing of large‐area, highly uniform perovskite films with micron grain size is reported. It is discovered that the releasing effect of these perovskite nanocapsules promotes homogeneous nucleation by diffusion‐controlled growth due to the steady‐state diffusion of the solute in solution. Remarkably, the printed PSCs and 25 cm2 modules achieve power conversion efficiencies of 22.10% and 16.12%, respectively. They exhibit negligible efficiency loss after continuous operation for over 1000 h under AM1.5 illumination, and excellent thermal (85 °C) stability with over 87% of the initial efficiency after aging for 500 h. This perovskite nanocapsules ink is expected to facilitate the high‐yield fabrication of perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

A low-temperature preparation process is significantly important for scalable and flexible devices. However, the serious interface defects between the normally used titanium dioxide (TiO2) electron transport layer (ETL) obtained via a low-temperature method and perovskite suppress the further improvement of perovskite solar cells (PSCs). Here, we develop a facile low-temperature chemical bath method to prepare a TiO2 ETL with tantalum (Ta) and niobium (Nb) co-doping. Systematic investigations indicate that Ta/Nb co-doping could increase the conduction band level of TiO2 and could decrease the trap-state density, boosting electron injection efficiency and reducing the charge recombination between the perovskite/ETL interface. A superior power conversion efficiency of 19.44% can be achieved by a planar PSC with a Ta/Nb co-doped TiO2 ETL, which is much higher than that of pristine TiO2 (17.60%). Our achievements in this work provide new insights on low-temperature fabrication of low-cost and highly efficient PSCs. [ABSTRACT FROM AUTHOR]

UV light always does great harm to perovskite solar cells, relentlessly degrading perovskites and shortening the lifetime of perovskite devices. Meanwhile, surface defects in perovskite films further accelerate the degradation process and serve as nonradiative charge recombination centers to deteriorate device efficiency. Herein, we demonstrate that a "sunscreen" molecule, 2‐hydroxy‐4‐methoxybenzophenone, not only protects the perovskite solar cell from UV degradation but also enables molecular defect passivation through interaction between functional groups and defects by molecular tautomerism under UV light illumination. Therefore, the sunscreen strategy efficiently enhances the UV endurance of PSCs and improves defect formation energy to −1.35 eV. The perovskite solar cell with sunscreen (sunscreen PSC) exhibits outstanding efficiencies of up to 23.09 % (0.04 cm2) and 19.73 % (1.00 cm2) as well as long‐term UV (UVa: 365 nm and UVb: 285 nm) stability. [ABSTRACT FROM AUTHOR]

The translation of unparalleled efficiency from the lab-scale devices to practical-scale flexible modules affords a huge performance loss for flexible perovskite solar cells (PSCs). The degradation is attributed to the brittleness and discrepancy of perovskite crystal growth upon different substrates. Inspired by robust crystallization and flexible structure of vertebrae, herein, we employ a conductive and glued polymer between indium tin oxide and perovskite layers, which simultaneously facilitates oriented crystallization of perovskite and sticks the devices. With the results of experimental characterizations and theoretical simulations, this bionic interface layer accurately controls the crystallization and acts as an adhesive. The flexible PSCs achieve the power conversion efficiencies of 19.87% and 17.55% at effective areas of 1.01 cm2 and 31.20 cm2 respectively, retaining over 85% of original efficiency after 7000 narrow bending cycles with negligible angular dependence. Finally, the modules are assembled into a wearable solar-power source, enabling the upscaling of flexible electronics. Flexible perovskite solar cells suffer huge efficiency loss upon area scale-up due to brittleness of ITO and poor perovskite film quality. Here Meng et al. solve this by inserting a conductive and glued polymer layer between ITO and perovskite layers and obtain efficiency of 17% for 30 cm2 devices. [ABSTRACT FROM AUTHOR]

A new crystal form of 1D perovskite (pyrrolidinium)PbI3 (orthorhombic phase) is synthesized and characterized. The 1D perovskite has a good film formability by solution spin coating and is in situ transformed to 3D CH3NH3PbI3 via the organic cation exchange approach in CH3NH2 atmosphere, which is dense and uniform. The converted 3D perovskite film is used as a light absorber, and the corresponding perovskite solar cell shows a power conversion efficiency of up to 19.2% under simulated 1 sun AM1.5G illumination (100 mW cm−2). [ABSTRACT FROM AUTHOR]

The low toxicity, narrow bandgaps, and high charge‐carrier mobilities make tin perovskites the most promising light absorbers for low‐cost perovskite solar cells (PSCs). However, the development of the Sn‐based PSCs is seriously hampered by the critical issues of poor stability and low power conversion efficiency (PCE) due to the facile oxidation of Sn2+ to Sn4+ and poor film formability of the perovskite films. Herein, a synthetic strategy is developed for the fabrication of methylammonium tin iodide (MASnI3) film via ion exchange/insertion reactions between solid‐state SnF2 and gaseous methylammonium iodide. In this way, the nucleation and crystallization of MASnI3 can be well controlled, and a highly uniform pinhole‐free MASnI3 perovskite film is obtained. More importantly, the detrimental oxidation can be effectively suppressed in the resulting MASnI3 film due to the presence of a large amount of remaining SnF2. This high‐quality perovskite film enables the realization of a PCE of 7.78%, which is among the highest values reported for the MASnI3‐based solar cells. Moreover, the MASnI3 solar cells exhibit high reproducibility and good stability. This method provides new opportunities for the fabrication of low‐cost and lead‐free tin‐based halide perovskite solar cells. [ABSTRACT FROM AUTHOR]

1,4‐butanediamine (BEA) is incorporated into FASnI3 (FA=formamidinium) to develop a series of lead‐free low‐dimensional Dion–Jacobson‐phase perovskites, (BEA)FAn−1SnnI3n+1. The broadness of the (BEA)FA2Sn3I10 band gap appears to be influenced by the structural distortion owing to high symmetry. The introduction of BEA ligand stabilizes the low‐dimensional perovskite structure (formation energy ca. 106 j mol−1), which inhibits the oxidation of Sn2+. The compact (BEA)FA2Sn3I10 dominated film enables a weakened carrier localization mechanism with a charge transfer time of only 0.36 ps among the quantum wells, resulting in a carrier diffusion length over 450 nm for electrons and 340 nm for holes, respectively. Solar cell fabrication with (BEA)FA2Sn3I10 delivers a power conversion efficiency (PCE) of 6.43 % with negligible hysteresis. The devices can retain over 90 % of their initial PCE after 1000 h without encapsulation under N2 environment. [ABSTRACT FROM AUTHOR]

Methylammonium bismuth iodide (MA3Bi2I9) has been recently investigated as a light absorber in lead-free perovskite solar cells. However, the MA3Bi2I9 film fabricated via conventional one-step spin coating methods usually has poor surface morphology, limiting the device performance. Herein, a cation displacement approach was employed for the fabrication of MA3Bi2I9 film, where (CH3CH2CH2NH3)3Bi2I9 (PA3Bi2I9) film was first deposited from a solution containing CH3CH2CH2NH3I and BiI3 and then transformed into MA3Bi2I9 film in a methylamine atmosphere. With the technique, the MA3Bi2I9 film was realized with smooth, uniform, and compact surface morphology. Using the MA3Bi2I9 film as a light absorber, a mesoporous photovoltaic device was fabricated with a power conversion efficiency of 0.33%, which is about two times higher than the value (0.15%) obtained for the one-step spin coating MA3Bi2I9 device. Moreover, the facile film fabrication strategy utilized in this work paves the way for high reproducibility of lead-free organic–inorganic halide films and devices. [ABSTRACT FROM AUTHOR]

Tin‐based halide perovskite materials have been successfully employed in lead‐free perovskite solar cells, but the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn2+ to Sn4+. Now a chemical route is developed for fabrication of high‐quality methylammonium tin iodide perovskite (MASnI3) films: hydrazinium tin iodide (HASnI3) perovskite film is first solution‐deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI2), and then transformed into MASnI3 via a cation displacement approach. With the two‐step process, a dense and uniform MASnI3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI3 as light harvester, mesoporous perovskite solar cells were prepared, and a maximum power conversion efficiency (PCE) of 7.13 % is delivered with good reproducibility. [ABSTRACT FROM AUTHOR]

Abstract: Achieving light harvesting is crucial for the efficiency of the solar cell. Constructing optical structures often can benefit from micro‐nanophotonic imprinting. Here, a simple and facile strategy is developed to introduce a large area grating structure into the perovskite‐active layer of a solar cell by utilizing commercial optical discs (CD‐R and DVD‐R) and achieve high photovoltaic performance. The constructed diffraction grating on the perovskite active layer realizes nanophotonic light trapping by diffraction and effectively suppresses carrier recombination. Compared to the pristine perovskite solar cells (PSCs), the diffraction‐grating perovskite devices with DVD obtain higher power conversion efficiency and photocurrent density, which are improved from 16.71% and 21.67 mA cm−2 to 19.71% and 23.11 mA cm−2. Moreover, the stability of the PSCs with diffraction‐grating‐structured perovskite active layer is greatly enhanced. The method can boost photonics merge into the remarkable perovskite materials for various applications. [ABSTRACT FROM AUTHOR]

The structural advantages and localized surface plasmon resonance (LSPR) effect of Ag@SiO2 nanowires when used as plasmonic antennas possess the features of fast electron transmission by 1D metal nanomaterials, high light harvesting, and electron-hole separation through the LSPR effect. By optimizing the concentration of Ag@SiO2 nanowires (0.06 wt%) in the active layer of a device, high power conversion efficiency of 18.03% and a negligible photocurrent hysteresis are obtained. [ABSTRACT FROM AUTHOR]

In this report, a novel and facile in situ gas-solid reaction method has been developed for the deposition of CdS quantum-dots (QDs) on a mesoscopic TiO film. In the approach, cadmium nitrate solution was first coated on mesoporous TiO films, and subsequently transformed into CdS QDs (with size about 2-3 nm) by reaction with hydrogen sulfide (HS) gas generated in a closed container at room temperature. Different from the conventional solution techniques, this method offers new opportunities for rapid and facile deposition of CdS QD-coated TiO films without the introduction of the by-products. With the CdS QDs-decorated TiO active electrodes, the liquid and solid solar cells were fabricated with power conversion efficiencies ( PCEs) of 1.90 and 0.80%, respectively. [ABSTRACT FROM AUTHOR]

The brittleness of perovskite (PVK) film restrains the development and application of the flexible perovskite solar cells (FPSCs). We utilize the polyurethane elastomers with disulfide bonds (PUDS) as a self-healing polymer to construct self-healing FPSCs and strengthen the self-healed perovskite film by the phase-locked state. The PUDS efficiently enhances the flexibility and self-healing properties of FPSCs. The champion efficiencies of MAPbI 3 on rigid and flexible substrates with PUDS are 20.30% and 17.19%, respectively. Importantly, the efficiency of cracked FPSC after thermal self-healing (80 °C) has been recovered from 12% (Broken: 2.06%) of the initial efficiency (17.19%) to 88% (Recovery: 15.12%). Besides, the efficiency of FPSC with PUDS maintains 95% of the initial value after 3000 h stored in glove box. This strategy provides an effective approach for developing flexible electronics. [Display omitted] • Polyurethane with disulfide bonds achieve the self-healing flexible perovskite solar cells by the phase-locked dynamic bonds. • The dynamic bonds of PUDS transform to the phase-locked state strengthening the self-healed perovskite film. • The efficiency of the cracked FPSC recovers from 12% (Broken: 2.06%) to 88% (Recovery: 15.12%) of the initial efficiency (17.19%) after the multiple bending-heal. • The FPSC with PUDS maintains 84% of the initial PCE after 4000 bending cycles at the radius of 3 mm. [ABSTRACT FROM AUTHOR]

The article discusses a study showing that the core-triple shell structured Au@SiO 2 @ Ag@SiO 2 nanoparticles are designed and synthesized by the wet-chemical approach, while the structure is characterized by transmission electron microscopy (TEM) and high angle annular dark field scanning (HAADF-STEM). It also proves the effect of SiO 2 as passivation layer on enhancing the surface plasmon resonance (SPR) to improve the light harvesting and reduce interfacial carrier recombination.

• The evolution of 2D perovskites based on multi-characteristic organic spacers is approached. • Impacts of the organic spacers on photophysical properties and film quality of 2D perovskites are discussed. • Several strategies to select and optimize the organic spacers for enhancing photovoltaic characteristics are proposed. [Display omitted] Two-dimensional (2D) perovskites have been attracting extensive attention due to their intrinsic stability compared with their three-dimensional (3D) counterparts. These materials are widely tailorable in composition, structure, and bandgap, and provide an intriguing playground for the solid-state chemistry and physics communities to uncover structure-property relationships. In the field of photovoltaic, the fabricated 2D perovskite solar cells (PSCs) have achieved high stability as well as sustainable breakthrough in power conversion efficiency (PCE). However, the PCE of 2D PSCs still lags far behind their 3D counterpart, which is attributed to the special physicochemical properties of organic ligands. This review focuses the 2D halide perovskites from a structural perspective, namely the Ruddlesden-Popper (RP) phases, Dion-Jacobson (DJ) phases, alternating cation in the interlayer space (ACI) phases and mixed organic ligands phases, which stems from the diversity and versatility of spacers. Then the impacts of the species, chemical compositions, and physical characteristics of spacers on 2D perovskites, especially on the structure, carrier behavior, and the specific properties of solar cells, were discussed. Finally, several strategies on the rational selection of novel spacers are elucidated, and an outlook toward high-performance of 2D PSCs is presented. [ABSTRACT FROM AUTHOR]

Formamidinium‐lead triiodide (FAPbI3) perovskite holds promise as a prime candidate in the realm of perovskite photovoltaics. However, the photo‐active α‐FAPbI3 phase, existing as a metastable state, is observable solely at elevated temperatures and is susceptible to degradation into the δ‐phase in ambient air. Therefore, the attainment of phase‐stable α‐FAPbI3 in ambient conditions has become a crucial objective in perovskite research. Here, we proposed an efficient conversion process of PbI2 into the α‐FAPbI3 perovskites in ambient air. This conversion was facilitated by the introduction of chelating molecules, which interacted with PbI2 to form an intermediate phase. Due to the reduced formation barrier resulting from the altered reaction pathway, this stable intermediate phase transitioned directly into α‐FAPbI3 upon the deposition of the organic cation solution, effectively bypassing the formation of δ‐FAPbI3. Consequently, the ambient‐fabricated FAPbI3 perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency of 25.08 %, along with a high open‐circuit voltage of 1.19 V. Furthermore, the unencapsulated devices demonstrated remarkable environmental stability. Notably, this innovative approach promises broad applicability across various chelating molecules, opening new avenues for further progress in the ambient air fabrication of FAPbI3 PSCs. [ABSTRACT FROM AUTHOR]

Perovskites, solar cells, tautomerism, UV stability Rücktitelbild: Tautomeric Molecule Acts as a "Sunscreen" for Metal Halide Perovskite Solar Cells (Angew. Keywords: perovskites; solar cells; tautomerism; UV stability EN perovskites solar cells tautomerism UV stability 9228 9228 1 04/03/21 20210412 NES 210412 B UV-Licht und Oberflächendefekte b beschleunigen den Degradationsprozess von Perowskit-Solarzellen (PSCs). [Extracted from the article]

Perovskites, solar cells, tautomerism, UV stability Keywords: perovskites; solar cells; tautomerism; UV stability EN perovskites solar cells tautomerism UV stability 9144 9144 1 04/03/21 20210412 NES 210412 B UV light and surface defects b accelerate the degradation process of perovskite solar cells (PSCs). Back Cover: Tautomeric Molecule Acts as a "Sunscreen" for Metal Halide Perovskite Solar Cells (Angew. [Extracted from the article]

Defects from grain interiors and boundaries of perovskite films cause significant nonradiative recombination energy loss, and thus perovskite films with controlled crystallinity and large grains is critical for improvement of both photovoltaic performance and stability for perovskite-based solar cells. Here, a methylamine (MA0) gas-assisted crystallization method is developed for fabrication of methylammonium lead iodide (MAPbI3) perovskite films. In the process, the perovskite film is formed via controlled release of MA0 gas molecules from a liquid intermediate phase MAPbI3·xMA0. The resulting perovskite film comprises millimeter-sized grains with (110)-uniaxial crystallographic orientation, exhibiting much low trap density, long carrier lifetime, and excellent environmental stability. The corresponding perovskite solar cell exhibits a power conversion efficiency (PCE) of ~ 21.36%, which is among the highest reported for MAPbI3-based devices. This method provides important progress towards the fabrication of high-quality perovskite thin films for low-cost, highly efficient and stable perovskite solar cells. Suppressing grain boundaries and defects in perovskite solar cells remains a quest to address the efficiency and stability issues. Here, the authors use methylamine gas for assisting the growth of uniaxial-oriented perovskite thin films with millimeter-sized grains. [ABSTRACT FROM AUTHOR]

Regioregular poly(3-hexylthiophene) (P3HT) was employed as a hole transport material and assistant light absorber for the fabrication of a CdS quantum dot-sensitized solid-state solar cell, by which a power-conversion efficiency of 1.42% was achieved under an AM1.5 G (100 mW cm−2) condition. [ABSTRACT FROM AUTHOR]

In this communication, a novel bulk heterojunction solar cell based on an electron donor–acceptor conjugated triphenylamine dye was fabricated, and a high conversion efficiency of 1.23% was achieved under AM 1.5 illumination (100 mW cm−2). [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PVSCs) are promising photovoltaic technologies for realizing power sources with outstanding power conversion efficiency (PCE) and low‐cost properties. However, the extraordinary photovoltaic performance can be maximized only if an extremely stabilized device structure is developed. Here, a novel glued poly(ethylene‐co‐vinyl acetate) (EVA) interfacial layer is introduced to fabricate highly efficient and stable PVSCs with excellent waterproofness and flexibility. This strategy can effectively passivate the perovskite surface, reduce defect density, and balance charge transfer, which leads to a champion PCE of 19.31% for a 0.1 cm2 device and 11.73% for a 25 cm2 solar module. More importantly, the formation of a glued EVA thin layer on the surface of perovskite can inhibit ionic migration to the Ag electrode, form favorable interfacial contact and adhesive interaction with the perovskite/[6,6]‐phenyl‐C61‐butyric acid methyl ester to sustain mechanical bending, and produce significant waterproofness from moisture invasion, thus facilitating improvement in the operational stability of the PVSCs. The EVA‐treated PVSCs exhibit superior PCE values of 15.12% for a flexible device (0.1 cm2) and 8.95% for a flexible module (25 cm2), as well as over 85% retention after 5000 bending cycles, which opens up a new strategy for the practical application of PVSCs in portable and wearable electronics. [ABSTRACT FROM AUTHOR]

The deposition of a uniform and dense tin‐based perovskite layer with low defect‐caused background carrier density is crucial for achieving efficient tin perovskite solar cells (PSCs). These defects are mainly caused by the rapid oxidation of Sn2+ to Sn4+ in tin perovskite during device fabrication. Herein, trihydrazine dihydriodide ((N2H4)3(HI)2) is used as an additive for solution deposition of a formamidinium tin iodide (FASnI3) perovskite layer. The resultant FASnI3 layer is homogeneous with full surface coverage; moreover, the content of Sn4+ is significantly reduced in the film from the SnI2 precursor owing to the reductive property of (N2H4)3(HI)2. With the high‐quality FASnI3 layer as a light absorber, planar‐heterojunction perovskite solar cells are fabricated, exhibiting a maximum power conversion efficiency of 8.48% and good reproducibility. This work opens new possibilities for achieving efficient lead‐free tin‐based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Highlights from the article: Keywords: competitive growth; micro-contact print; perovskites; solar cells; surface wettability In article number 1900838, Mingzhu Li, Yanlin Song and co-workers report a competitive perovskite grain growth approach via a micro-contact print (MicroCP) method with CD discs as templates for printing a wettability-patterned substrate, to achieve a large-grained perovskite and avoid discontinuous perovskite films caused by the low wettability of substrates, resulting in efficiencies over 20% for the MicroCP perovskite solar cells. Competitive growth, micro-contact print, perovskites, solar cells, surface wettability.

Novel photovoltaic perovskite solar cells (PSCs) with high‐efficient photovoltaic property are largely in thrall to the uncertain perovskite grain size and inevitable defects. Here, inspired by the competitive growth between tree and grass in the forest system, a competitive perovskite grain growth approach via micro‐contact print (MicroCP) method (CD disk as templates) for printing wettability‐patterned substrate is proposed, aiming to achieve large‐grained perovskite and avoid discontinuous perovskite films caused by the low wettability of substrates. A MicroCP process is employed to construct a patterned wettability surface for the perovskite competitive growth mechanism on the electrode surface. This approach modifies the substrates quickly, ensures the uniform coverage of perovskite due to the function of ‐NH2 and Pb2+ bonds, and converts the perovskite films composed of small grains and pinholes into high‐quality perovskite films, free from pinholes and made up of large grains, resulting in efficiencies over 20% for the MicroCP PSCs. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid perovskite materials have recently been identified as a promising light absorber for solar cells. In the efficient solar cells, the perovskite active layer has generally been fabricated by either vapor deposition or two-step sequential deposition process. Herein, electrochemically deposited PbO film is in situ converted into CH3NH3PbI3 through solid-state reaction with adjacent CH3NH3I layer, exhibiting a large-scale flat and uniform thin film with fully substrate coverage. The resultant planar heterojunction photovoltaic device yields a best power conversion efficiency of 14.59% and an average power conversion efficiency of 13.12 ± 1.08% under standard AM 1.5 conditions. This technique affords a facile and environment-friendly method for the fabrication of the perovskite based solar cells with high reproducibility, paving the way for the practical application. [ABSTRACT FROM AUTHOR]