Solution-processed perovskites offer tremendous potential for low-cost, high-throughput photovoltaic production. However, high-quality perovskite films typically require stringent processing conditions, compromising reliability in large-scale production. Here, we discover that the initial nucleation process during the spin-coating is critical in determining the film quality. This process is highly sensitive to ambient temperature (T A) and associated with the effectiveness of intermediate phase formation. Besides the general wisdom that the intermediate phase regulates the initial nucleation by temporarily consuming precursor ions, we find that the intermediate phase plays a key role in guaranteeing high film quality by spatially separating the nuclei to mitigate thermally activated nuclei aggregation. By stabilizing a strongly coordinated intermediate phase, we achieve perovskite solar cells (PSCs) with power conversion efficiencies of 24% to 25%, even T A elevated to 28 degrees C. This work offers valuable insights into enhancing the reliability of PSCs and provides a deeper understanding of the role of the intermediate phase in the solution-processing of perovskite films.

Constructing low-dimensional/three-dimensional (LD/3D) perovskite solar cells can improve efficiency and stability. However, the design and selection of LD perovskite capping materials are incredibly scarce for inverted perovskite solar cells (PSCs) because LD perovskite capping layers often favor hole extraction and impede electron extraction. Here, we develop a facile and effective strategy to modify the perovskite surface by passivating the surface defects and modulating surface electrical properties by incorporating morpholine hydriodide (MORI) and thiomorpholine hydriodide (SMORI) on the perovskite surface. Compared with the PI treatment that we previously developed, the one-dimensional (1D) perovskite capping layer derived from PI is transformed into a two-dimensional (2D) perovskite capping layer (with MORI or SMORI), achieving dimension regulation. It is shown that the 2D SMORI perovskite capping layer induces more robust surface passivation and stronger n-N homotype 2D/3D heterojunctions, achieving a p-i-n inverted solar cell with an efficiency of 24.55%, which retains 87.6% of its initial efficiency after 1500 h of operation at the maximum power point (MPP). Furthermore, 5 × 5 cm2 perovskite mini-modules are presented, achieving an active-area efficiency of 22.28%. In addition, the quantum well structure in the 2D perovskite capping layer increases the moisture resistance, suppresses ion migration, and improves PSCs' structural and environmental stability.

Ionic hybrid perovskites face challenges in maintaining their structural stability against non-equilibrium phase degradation, therefore, it is essential to develop effective ways to reinforce their corner-shared [PbI6]4- octahedral units. To strengthen structural stability, redox-active functional polyoxometalates (POMs) are developed and incorporated into perovskite solar cells (PSCs) to form a robust polyoxometalates/perovskite interlayer for stabilizing the perovskite phase. This approach offers several advantages: 1) promotes the formation of an interfacial connecting layer to passivate interfacial defects in addition to stabilize the [PbI6]4- units through exchanged ammonium cations in POMs with perovskites; 2) facilitates continuous structural repairing of Pb0- and I0-rich defects in the [PbI6]4- unit through redox electron shuttling of the electroactive metal ions in POMs; 3) provides guidance for selecting suitable redox mediators based on the kinetic studies of POM's effectiveness in reacting with targeted defects. The POM-reinforced device maintains 97.2% of its initial PCE after 1500 h of shelf-life test at 65 °C, while also enhancing the long-term operational stability. Additionally, this approach can be generally applicable across scalable sizes and various bandgap perovskites in devices, showing the promise of using functional POMs to enhance perovskite photovoltaic performance.

Zinc batteries hold promise for grid-scale energy storage due to their safety and low cost. A key challenge for the field is identifying cathode materials that can undergo reversible redox reactions at the extreme potentials required for realizing high energy density devices. While organic materials have been extensively explored as cathode materials due to their structural tunability and eco-friendliness, most reported zinc-organic batteries exhibit a voltage lower than 1.2 V. In this report, by employing rational molecular design and synthesis, computational analysis, and electrochemical evaluation, the well-studied neutral p-type N-centered is redesigned, triphenylamine organic cathode by replacing three phenyl rings with the smallest aromatic system - cationic cyclopropenium. This results in a novel class of cathode materials with simultaneously enhanced potential, capacity, and stability. The resultant full battery exhibits a high discharge voltage of 1.7 V and an outstanding capacity retention of 95% after 10000 cycles at a discharge capacity of 157.5 mAh g-1cation (103.9 mAh g-1salt). In this report, by employing rational molecular design and synthesis, computational analysis, and electrochemical evaluation, the well-studied neutral p-type N-centered, triphenylamine organic cathode is redesigned by replacing three phenyl rings with the smallest aromatic system - cationic cyclopropenium. This results in a novel class of cathode materials with simultaneously enhanced potential, capacity, and stability.image

Inverted perovskite solar cells (PSCs) have attracted considerable attention due to their distinct advantages, including minimal hysteresis, cost-effectiveness, and suitability for tandem applications. Nevertheless, the solution processing and the low formation energy of perovskites inevitably lead to numerous defects formed at both the bulk and interfaces of the perovskite layer. These defects can act as non-radiative recombination centers, significantly impeding carrier transport and posing a substantial obstacle to stability and further enhancing power conversion efficiency (PCE). This review delves into a detailed discussion of the nature and origin of defects and the characterization techniques employed for defect identification. Furthermore, it systematically summarizes methods for defect detection and approaches for passivating interface and bulk defects within the perovskite film in inverted PSCs. Finally, this review offers a perspective on employing upscaling defect passivation engineering for perovskite modules. It is hoped this review provides insights into defect passivation in inverted PSCs and solar modules. This review article examines the advancements in defect passivation for inverted perovskite solar cells over the last decade, focusing on passivation methodologies targeting the buried interface, top surface, and perovskite bulk. It delves into characterization techniques for defect identification, device optimization, large-area fabrication, and commercial application potential, providing insights into the future of renewable energy through inverted perovskite solar modules. image

The persistency of passivation and scalable uniformity are vital issues that limit the improvement of performance and stability of large-area perovskite solar modules (PSMs). Here, we design a bilayer interface engineering strategy that takes advantage of the stability and passivation ability of low-dimensional perovskite and the dipole layer. Introducing phenethylammonium iodide (PEAI) can form 2D/3D heterojunctions on the perovskite surface and effectively passivate defects of perovskite film. Interestingly, the upper piperazinium iodide (PI) layer can still form surface dipoles on the 2D/3D perovskite surface to optimize energy-level alignment. Moreover, the bilayer interface engineering enables large-area perovskite films with uniform surface morphology, lower trap-state density and stability against environmental stress factors. The final devices achieved a small-area PCE of 25.20% and a large-area (1 cm2) PCE of 23.96%. A perovskite mini-module (5 x 5 cm2 with an active area of 14.28 cm2) could also be fabricated to achieve a PCE of 23.19%, ranking it among the highest for inverted PSMs. Additionally, the device could retain over 93% of its initial efficiency after MPP tracking at 45 degrees C for 1280 h. This study successfully demonstrates a bilayer interface engineering with respective functions, offering valuable in- sights for producing efficient and stable large-area PSCs.

Inverted perovskite solar cells (PSCs) are preferred for tandem applications due to their superior compatibility with diverse bottom solar cells. However, the solution processing and low formation energy of perovskites inevitably lead to numerous defects at both the bulk and interfaces. We report a facile and effective strategy for precisely modulating the perovskite by incorporating AlOx deposited by atomic layer deposition (ALD) on the top interface. We find that Al3+ can not only infiltrate the bulk phase and interact with halide ions to suppress ion migration and phase separation but also regulate the arrangement of energy levels and passivate defects on the perovskite surface and grain boundaries. Additionally, ALD-AlOx exhibits an encapsulation effect through a dense interlayer. Consequently, the ALD-AlOx treatment can significantly improve the power conversion efficiency (PCE) to 21.80 % for 1.66 electron volt (eV) PSCs. A monolithic perovskite-silicon TSCs using AlOx-modified perovskite achieved a PCE of 28.5 % with excellent photothermal stability. More importantly, the resulting 1.55 eV PSC and module achieved a PCE of 25.08 % (0.04 cm2) and 21.01 % (aperture area of 15.5 cm2), respectively. Our study provides an effective way to efficient and stable wide-band gap perovskite for perovskite-silicon TSCs and paves the way for large-area inverted PSCs.

Halide segregation and energy loss pose significant challenges for wide-bandgap perovskite solar cells, impairing their photovoltage and device stability. These issues are often exacerbated by inferior film quality and inhomogeneous halide distribution due to unbalanced crystallization processes. To address these challenges, we developed a novel strategy using a cation alloy that not only tailors the lattice properties and crystallization but also effectively passivates the defects. This approach enables homogeneous halide distribution and substantially reduced defect density. These improvements have led to a remarkable power conversion efficiency (PCE) of 19.50% with a record open-circuit voltage of 1.35 V for 1.79 eV perovskite solar cells, approaching similar to 90% of its S-Q limit. Furthermore, the champion device could maintain 93% of its initial efficiency after operating at its maximum power point for 500 hours. By integrating these perovskite devices into a monolithic perovskite-organic tandem solar cell (PO-TSC) as the wide-bandgap subcell, we demonstrated a high PCE of 25.54%. This efficiency is among the highest values reported for PO-TSCs, presenting a significant step forward in these promising tandem cells.

Dopant-free polymer hole transport materials (HTMs) exhibit high thermal stability, hydrophobicity and filmprocessing capabilities, demonstrating excellent device efficiency and stability in perovskite solar cells (PSCs). Continued innovation of wide-bandgap polymers in organic photovoltaics (OPV) provides a valuable toolbox for developing polymeric HTMs. Here, we propose an effective molecule design for selecting structurally relevant polymers (D18, D18-Cl, PBQx-TCl) available for commercialization. We discover that the highly planar conjugated backbones play a crucial role in regulating the packing orientation of the film relative to the perovskite. The moderate aggregation with face-on packing orientation is conducive to the high-quality film, which is responsible for better contact with perovskite and superior charge extraction and transport. Simultaneously, these polymers with robust passivation enhanced the open circuit voltage (V-OC) without additional passivation layers, streamlining the device process. Consequently, a PSC using dopant-free PBQx-TCl HTL demonstrated an efficiency of 24.12 % with a high VOC of 1.20 V and good operational stability (T-90 > 600 h). This work reveals transparent structure-function-performance relationships between molecules and devices, paving the way for the subsequent development of high-performance HTMs.

The hygroscopic dopants used in Spiro‐OMeTAD hole‐transport materials (HTMs) in n–i–p perovskite solar cells (PSCs) inevitably cause device degradation. Herein, two polymer interface materials based on lead anchoring groups are developed. It is found that 2D polymers 2DP‐BT and 2DP‐Por can form dense films and exhibit excellent hydrophobicity. Importantly, 2DP‐Por can passivate the surface defects through noncovalent interactions, reducing nonradiative recombination loss. After introducing these polymer interface materials between the perovskite layer and the HTM layer, the optimized devices using 2DP‐Por and 2DP‐BT achieve champion power conversion efficiency of 24.12% and 23.29%, respectively, and the stability is significantly improved. These results indicate that developing polymer interface materials containing lead anchoring groups can improve PSC efficiency and stability and elucidate critical molecular design rules for interface materials.

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells. The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs. In this work, we adopted a solid–liquid two-step film formation technique, which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films. This method possesses the advantages of integrating vapor deposition and solution methods, which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform, large-area perovskite film. Furthermore, modification of the NiO x /perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization. As a result, a large-area perovskite film possessing larger grains, fewer pinholes, and reduced defects could be achieved. The inverted PSM with an active area of 61.56 cm 2 (10 × 10 cm 2 substrate) achieved a champion power conversion efficiency of 20.56% and significantly improved stability. This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

Multiple cation-composited perovskites are demonstrated as a promising approach to improving the performance and stability of perovskite solar cells (PSCs). However, recipes developed for fabricating high-performance perovskites in laboratories are always not transferable in large-scale production, as perovskite crystallization is highly sensitive to processing conditions. Here, using an in situ optical method, the ambient temperature effect on the crystallization process in multiple cation-composited perovskites is investigated. It is found that the typical solvent-coordinated intermediate phase in methylammonium lead iodide (MAPbI3) is absent in formamidinium lead iodide (FAPbI3), and nucleation is almost completed in FAPbI3 right after spin-coating. Interestingly, it is found that there is noticeable nuclei aggregation in Formamidinium (FA)-based perovskites even during the spin-coating process, which is usually only observed during the annealing in MAPbI3. Such aggregation is further promoted at a higher ambient temperature or in higher FA content. Instead of the general belief of stress release-induced crack formation, it is proposed that the origin of the cracks in FA-based perovskites is due to the aggregation-induced solute depletion effect. This work reveals the limiting factors for achieving high-quality FA-based perovskite films and helps to unlock the existing narrow processing window for future large-scale production.

Functional additives that can interact with the perovskite precursors to form the intermediate phase have been proven essential in obtaining uniform and stable α-FAPbI3 films. Among them, Cl-based volatile additives are the most prevalent in the literature. However, their exact role is still unclear, especially in inverted perovskite solar cells (PSCs). In this work, we have systematically studied the functions of Cl-based volatile additives and MA-based additives in formamidinium lead iodide (FAPbI3)-based inverted PSCs. Using in situ photoluminescence, we provide clear evidence to unravel the different roles of volatile additives (NH4Cl, FACl, and MACl) and MA-based additives (MACl, MABr, and MAI) in the nucleation, crystallization, and phase transition of FAPbI3. Three different kinds of crystallization routes are proposed based on the above additives. The non-MA volatile additives (NH4Cl and FACl) were found to promote crystallization and lower the phase-transition temperatures. The MA-based additives could quickly induce MA-rich nuclei to form pure α-phase FAPbI3 and dramatically reduce phase-transition temperatures. Furthermore, volatile MACl provides a unique effect on promoting the growth of secondary crystallization during annealing. The optimized solar cells with MACl can achieve an efficiency of 23.1%, which is the highest in inverted FAPbI3-based PSCs.

Stable lead-free hybrid halide double perovskites have sparked widespread interest as a new kind of photoelectric material. Herein, for the first time, we successfully incorporated copper(I) and antimony(III) into two two-dimensional (2D) hybrid bimetallic double perovskite iodides, namely (NH3C6H11)4CuSbI8·H2O (CuSbI-1) and (NH3C6H10NH3)2CuSbI8·0.5H2O (CuSbI-2), using cyclohexylamine and 1,4-cyclohexanediamine as organic components. The band gaps for CuSbI-1 and CuSbI-2 were determined to be 2.22(2) eV and 2.21(2) eV, respectively. Furthermore, these two layered perovskites were readily dissolved in an organic solvent (1 mL DMF can dissolve 1 g sample for each compound) and could form smooth, pinhole-free, and uniform thin films through a facile spin-coating method. Photocurrent experiments with xenon lamp irradiation revealed the obvious photoelectric responses for both 2D double perovskites. The ratio of the photocurrent to the dark current (Ilight/Idark) for CuSbI-1 and CuSbI-2 is about 23 and 10, respectively, further suggesting their potential to be applied as light harvesters or light detectors. More importantly, these 2D double perovskite iodides show high moisture and thermal stabilities, indicating their potential for optoelectronic applications.

Self-assembled monolayers (SAMs) are widely employed as effective hole-selective layers (HSLs) in inverted perovskite solar cells (PSCs). However, most SAM molecules are amphiphilic in nature and tend to form micelles in the commonly used alcoholic processing solvents. This introduces an extra energetic barrier to disassemble the micelles during the binding of SAM molecules on the substrate surface, limiting the formation of a compact SAM. To alleviate this problem for achieving optimal SAM growth, a co-solvent strategy to disassemble the micelles of carbazole-based SAM molecules in the processing solution is developed. This effectively increases the critical micelle concentration to be above the processing concentration and enhances the reactivity of the phosphonic acid anchoring group to allow densely packed SAMs to be formed on indium tin oxide. Consequently, the PSCs derived from using MeO-2PACz, 2PACz, and CbzNaph SAM HSLs show universally improved performance, with the CbzNaph SAM-derived device achieving a champion efficiency of 24.98% and improved stability.

The buried interface in perovskite solar cells (PSCs) is pivotal for achieving high efficiency and stability. However, it is challenging to study and optimize the buried interface due to its non-exposed feature. Here, a facile and effective strategy is developed to modify the SnO2/perovskite buried interface by passivating the buried defects in perovskite and modulating carrier dynamics via incorporating formamidine oxalate (FOA) in SnO2 nanoparticles. Both formamidinium and oxalate ions show a longitudinal gradient distribution in the SnO2 layer, mainly accumulating at the SnO2/perovskite buried interface, which enables high-quality upper perovskite films, minimized defects, superior interface contacts, and matched energy levels between perovskite and SnO2. Significantly, FOA can simultaneously reduce the oxygen vacancies and tin interstitial defects on the SnO2 surface and the FA(+)/Pb2+ associated defects at the perovskite buried interface. Consequently, the FOA treatment significantly improves the efficiency of the PSCs from 22.40% to 25.05% and their storage- and photo-stability. This method provides an effective target therapy of buried interface in PSCs to achieve very high efficiency and stability.

Developing 3D conductive aligned cryogels has great potential for skeletal muscle trauma treatment because they can mimic anisotropic structure, conductivity, and recoverable cyclic compression of the microenvironment of native skeletal muscle. In this work, a series of cryogels possessing 3D aligned morphology, conductivity, and excellent anisotropic mechanical compression property based on gelatin (GT) and polydopamine coated carbon nanotubes (PCNTs) were fabricated as skeletal muscle tissue scaffolds by using unidirectional freeze casting technology. The aligned microstructure of cryogels depended on gelatin concentration, and GT7.5 (with the gelatin content of 7.5% w/v) showed excellent aligned structure. Interestingly, the mechanical property of the aligned cryogels was similar to that of native skeletal muscle in terms of the dynamic contraction behavior and the anisotropic compression property due to the internal anisotropy structure. The aligned cryogel GT7.5 with good biocompatibility significantly promoted the alignment and elongation of C2C12 myoblasts. Moreover, the introduction of PCNTs enhanced the mechanical properties of cryogel GT7.5 and had a positive effect on myogenic differentiation of C2C12 cells. The aligned conductive GT7.5C2 cryogel significantly promoted new born muscle tissue generation compared to non-aligned group (GT7.5C2N) and non-conductive group (GT7.5) in a rat tibialis anterior muscle defect model. These data suggested that the 3D aligned conductive cryogel with conductivity and anisotropic compression property is a promising scaffold candidate for skeletal muscle tissue engineering.

Despite the rapidly increased power conversion efficiency (PCE) of perovskite solar cells (PVSCs), it is still quite challenging to bring such promising photovoltaic technology to commercialization. One of the challenges is the upscaling from small-sized lab devices to large-scale modules or panels for production. Currently, most of the efficient inverted PVSCs are fabricated on top of poly[bis(4-phenyl)(2, 4, 6-trimethylphenyl)amine] (PTAA), which is a commonly used hole-transporting material, using spin-coating method to be incompatible with large-scale film deposition. Therefore, it is important to develop proper coating methods such as blade-coating or slot-die coating that can be compatible for producing large-area, high-quality perovskite thin films. It is found that due to the poor wettability of PTAA, the blade-coated perovskite films on PTAA surface are often inhomogeneous with large number of voids at the buried interface of the perovskite layer. To solve this problem, self-assembled monolayer (SAM)-based hole-extraction layer (HEL) with tunable headgroups on top of the SAM can be modified to provide better wettability and facilitate better interactions with the perovskite coated on top to passivate the interfacial defects. The more hydrophilic SAM surface can also facilitate the nucleation and growth of perovskite films fabricated by blade-coating methods, forming a compact and uniform buried interface. In addition, the SAM molecules can also be modified so their highest occupied molecular orbital (HOMO) levels can have a better energy alignment with the valence band maxima (VBM) of perovskite. Benefitted by the high-quality buried interface of perovskite on SAM-based substrate, the champion device shows a PCE of 18.47% and 14.64% for the devices with active areas of 0.105 cm2 and 1.008 cm2, respectively. In addition, the SAM-based device exhibits decent stability, which can maintain 90% of its initial efficiency after continuous operation for over 500 h at 40 ℃ in inert atmosphere. Moreover, the SAM-based perovskite mini-module exhibits a PCE of 14.13% with an aperture area of 18.0 cm2. This work demonstrates the great potential of using SAMs as efficient HELs for upscaling PVSCs and producing high-quality buried interface for large-area perovskite films.

Two new 2D semiconducting Cs/Bi hybrid compounds are reported here with evident photocurrent responses.

This work presents high-performance and stable all-inorganic perovskite/organic tandem solar cells with a champion efficiency of 18.06% and excellent stability under light and thermal conditions.