In recent years, tandem solar cells (TSCs) have achieved remarkable progress. Nevertheless, wide-bandgap perovskite solar cells (WBG PSCs), typically employed as the top cell, still suffer from significant open-circuit voltage (VOC) losses. One contributing factor is the deeper valence band of WBG PSCs compared with conventional bandgap counterparts, which results in energy-level mismatch when conventional hole transport materials are used in p-i-n structured PSCs. Moreover, the top-down crystallization process of perovskite films frequently induces defect states at the buried interface, underscoring the urgent need for advanced passivation strategies. Here, we introduce poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylammoniumpropyl)-2,7-fluorene-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN-Br) as an interlayer between 2PACz and the perovskite absorber. The bromide-counterion ammonium groups in PFN-Br effectively suppress non-radiative recombination, while simultaneously tuning the energy-level alignment, thereby facilitating more efficient hole extraction in WBG PSCs. As a result, the PFN-Br-modified devices deliver a champion power conversion efficiency of 23.15% and a high VOC of 1.281 V for perovskite cells with a bandgap of 1.67 eV.

Redox mediators in water-in-salt electrolytes (WiSE) offer a compelling platform for durable, safe, and efficient Zn-ion battery. Here we investigate two model systems: MnCl2 and HAuCl4 dissolved in 15 m ZnCl2. Using a carbon positive electrode enables areal capacities of approx. 1 mAh/cm2, outperforming traditional electrodes with solid thin-film materials, e.g., phosphate olivines. This capacity is available in a WiSE volume, which fits the standard 2032 coin cell. The WiSE environment substantially alleviates the "dead MnO2" problem, while gamma-MnO2 is generated by anodic oxidation of Mn2+ over a broad potential region. The charge transfer is diffusion-limited, with ion transport primarily controlled by the viscosity of the WiSE. Remarkably, Au and Mn display strikingly similar electrochemical signatures, each producing broad, asymmetric voltammetric peaks with a formal potential near 1.7 V vs Zn2+/Zn, despite Mn redox couples being shifted by ca. 0.7 V below their standard potentials. The observed potential shifts arise from chloromanganate formation as well as from WiSE-specific effects. The potentials are conveniently referenced to the Ru(NH3)63+/2+ couple, which is essentially insensitive to ZnCl2 concentration. Gold undergoes rapid oxidative dissolution to AuCl4- . The Au-Zn alloys are identified by distinct features at anodic stripping, as well as by SEM, EDX and XPS. These findings highlight both the opportunities and mechanistic complexities of liquid-phase redox mediators for high-capacity Zn-ion energystorage systems with WiSE.

In this work, we present a high-performance, stable formamidinium lead iodide (FAPI) perovskite solar cell (PSC) achieved through the use of 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) bulk passivation and rapid photonic annealing. Utilizing flash infrared annealing (FIRA), we fabricated TEMPO-FAPI PSCs with a power conversion efficiency (PCE) exceeding 20%, exceeding the prior state of the art for this process. The TEMPO additive promotes enhanced crystallization dynamics, yielding films with improved homogeneity and reduced defect densities, as confirmed by photoluminescence (PL), profilometry, and positron annihilation lifetime spectroscopy (PALS). Stability testing under ISOS protocols demonstrated that the TEMPO-FAPI devices retained over 90% of their initial PCE after 4,296 h of operational and thermal stress, showing unprecedented longevity for a rapid processing technique. TEMPO's primary effect on passivating grain boundaries and surface defects is evidenced by a significantly reduced non-radiative recombination rate and low defect density, establishing this molecule as a promising additive for scalable, durable FAPI PSC manufacturing.

The electron transport layer (ETL) is a crucial component of perovskite solar cells (PSCs) as it greatly influences their photovoltaic performance. Among various currently used ETL materials, SnO₂ stands out due to its unique advantages, including low-temperature fabrication and rapid electron extraction capability and excellent energy match of its conduction band edge with that of the commonly used perovskite formulations. However, the currently employed SnO₂ layers contain surface defects, such as hydroxyl groups and oxygen vacancies that impair the desired growth of highly crystalline and defect less perovskite films during solution processing of n-i-p type PSCs reducing their power conversion efficiency (PCE) and stability. Here, a self-assembled monolayer (SAM) is introduced of dopamine hydrochloride (DACl) on the SnO2 film, whose catechol moiety adheres strongly to the SnO2 surface, while its methylammonium groups template the growth of the perovskite layer. Introducing the dopamine SAM at the interface between the ETL and the perovskite increases substantially the solar-to-electric PCE while greatly enhancing the PSC stability. This findings demonstrate the surprising benefits of this well-known neurotransmitter for the photovoltaic performance of PSCs which this is rationalized here by DFT and ab initio molecular dynamics calculations.

Metal halide perovskites have shown exceptional potential in converting solar energy to electric power in photovoltaics, yet their application is hampered by limited operational stability. This stimulated the development of hybrid layered (two-dimensional, 2D) halide perovskites based on hydrophobic organic spacers, templating perovskite slabs, as a more stable alternative. However, conventional organic spacer cations are electronically insulating, resulting in charge confinement within the inorganic slabs, thus limiting their functionality. This can be ameliorated by extending the π-conjugation of the spacer cations. We demonstrate the capacity to access Ruddlesden-Popper and Dion-Jacobson 2D perovskites incorporating for the first time aryl-acetylene-based (4-ethynylphenyl)methylammonium (BMAA) and buta-1,3-diyne-1,4-diylbis(4,1-phenylene)dimethylammonium (BDAA) spacers, respectively. We assess their unique opto(electro)ionic characteristics by a combination of techniques and apply them in mixed-dimensional perovskite solar cells that show superior device performances with a power conversion efficiency of up to 23 % and higher operational stability, opening the way for multifunctionality in layered hybrid materials and their application.

Perovskite solar cells have garnered significant interest, yet their limited operational stability remains a major challenge. This is especially pronounced at the interface with charge transport layers. In inverted p-i-n perovskite solar cells, fullerene-based electron transport layers pose critical stability issues. This has stimulated the application of low-dimensional perovskite interlayers featuring alkylammonium-based organic spacers that template perovskite slabs to enhance operational stabilities. However, these materials are traditionally based on organic cations that are electronically insulating, limiting charge extraction and device performance. We demonstrate the capacity to access low-dimensional perovskites incorporating electron-accepting naphthalimide- and naphthalenediimide-based spacers and use the corresponding organic moieties to modify or replace fullerene electron-transport layers, forming an electroactive interface that serves charge-transport. This resulted in superior performance with power conversion efficiencies exceeding 20% and enhanced operational stability, highlighting the potential of electroactive interlayers for advancing inverted perovskite solar cells.

Perovskite solar cells (PSCs) with ammonium passivation exhibit superior device performance and stability. Beyond typical chemical passivation, ammonium salts control the electronic structure of perovskite surfaces, yet the molecular structure-property relationship requires further understanding, especially the dipole effect. Here, we employed carbazole and its halogenated counterpart as the functional group of ammonium salts. 2-Chloro-carbazol-9-ethylammonium iodide (CzCl-EAI) with a rigid, conjugated molecular structure further provides chemical passivation and enhances the ambient stability of perovskites. In addition, we found that halogenation enhances the intramolecular charge transfer for a larger molecular dipole moment, leading to the depletion region of perovskite films threefold wider than that of the PDAI2 condition. The power conversion efficiency (PCE) of inverted PSCs based on mixed passivation reached 25.16% and certified 24.35% under the quasi-steady-state (QSS) measurement. Unencapsulated devices retained over 91% of initial PCE under ISOS-D-2 conditions over 1100 h and maintained 80% of their initial performance after 500 h of continuous light illumination in ambient air with a 50-60% relative humidity (RH).

A-site cation mixing can enhance the photovoltaic performance of a wide-bandgap (WBG) perovskite, but rubidium (Rb) cation mixing generally forms a nonperovskite phase. We report that lattice strain locks Rb ions into the α-phase of the lattice of a triple-halide WBG perovskite, preventing phase segregation into a nonperovskite Rb-cesium–rich phase. This process cooperates with chloride accommodation and promotes halide homogenization across the entire film volume. The resulting 1.67–electron volt WBG perovskite exhibits photoluminescence quantum yields exceeding 14% under 1-sun-equivalent irradiation, corresponding to a quasi–Fermi level splitting of ~1.34 electron volts. A WBG perovskite solar cell with an open-circuit voltage ( V OC ) of 1.30 volts was prepared, corresponding to 93.5% of the radiative V OC limit and representing the lowest photovoltage loss relative to the theoretical limit observed in WBG perovskites.

Engineering at interface between perovskite and charge transport layers is crucial for improving operational stability. In inverted perovskite solar cells (PSCs) with a core configuration of HTL/perovskite/ETL/HBL (HTL = hole transporting layer; ETL = electron transporting layer; HBL = hole blocking layer), the interfaces at ETL based on phenyl‐C 61 ‐butyric acid methyl ester (PCBM) are more defective due to its molecular geometry, leading to imperfect adhesion. We introduce the dual interlayer passivation at perovskite/PCBM and PCBM/HBL to enhance the adhesion and passivate interlayers. Materials for engineering the dual interfaces require different functional groups, where carbamylcholine chloride at the perovskite/PCBM interface results in a more compact PCBM layer, while γ‐butyrobetaine hydrochloride is suitable for passivating the interface between PCBM and HBL, leading to reduction in charge accumulation and improving electron transport. The dual interlayer passivation minimizes the device degradation induced by continuous light exposure and mechanical stress. As a consequence, the target device retains over 80% of its initial performance after 500 hours of maximum power point tracking (MPPT) under one sun illumination, and over 95% after 10 000 bending cycles at 5 mm radius. Both conditions exhibit more than 7‐fold enhancement in light‐soaking and bending stability than the unpassivated control devices.

Aqueous zinc-ion batteries have emerged as promising candidates for safe and cost-effective energy storage, yet their performance remains constrained by electrode stability and electrolyte composition. In this study, we investigate the electrochemical behavior of various electrode materials utilizing water-in-salt dual-ion electrolytes. Our findings highlight the critical influence of substrate materials on electrochemical stability, with titanium exhibiting superior anodic stability compared to, e.g., aluminum. Furthermore, we demonstrate the feasibility of LiFePO4 as a positive electrode, revealing a redox potential of 1.17 V vs. Zn2+/Zn in chloride-based electrolyte, which shifts positively with increasing lithium concentration. The observed potential variation with electrolyte composition underscores the need for optimized formulations to enhance the battery performance. Additionally, while LiMnPO4 offers a higher theoretical voltage, its cycling stability remains limited, suggesting that material modifications are necessary. Finally, we highlight the overlooked impact of electrolyte impurities on battery performance, emphasizing the importance of high-purity electrolyte components. These insights contribute to the development of more stable and efficient Zn-ion batteries, paving the way for their practical deployment in energy storage applications.

Hybrid metal halide perovskites have demonstrated remarkable performances in modern photovoltaics, although their stabilities remain limited. We assess the capacity to advance their properties by relying on interfacial modulators featuring helical chirality based on P,M-(1-methylene-3-methyl-imidazolium)[6]helicene iodides. We investigate their characteristics, demonstrating comparable charge injection for enantiomers and the racemic mixture. Overall, they maintain the resulting photovoltaic performance while improving operational stability, challenging the role of helical chirality in the interfacial modulation of perovskite solar cells.

The presence of defects at the interface between the perovskite film and the carrier transport layer poses significant challenges to the performance and stability of perovskite solar cells (PSCs). Addressing this issue, we introduce a dual host-guest (DHG) complexation strategy to modulate both the bulk and interfacial properties of FAPbI3-rich PSCs. Through NMR spectroscopy, a synergistic effect of the dual treatment is observed. Additionally, electro-optical characterizations demonstrate that the DHG strategy not only passivates defects but also enhances carrier extraction and transport. Remarkably, employing the DHG strategy yields PSCs with power conversion efficiencies (PCE) of 25.89% (certified at 25.53%). Furthermore, these DHG-modified PSCs exhibit enhanced operational stability, retaining over 96.6% of their initial PCE of 25.55% after 1050 hours of continuous operation under one-sun illumination, which was the highest initial value in the recently reported articles. This work establishes a promising pathway for stabilizing high-efficiency perovskite photovoltaics through supramolecular engineering, marking a significant advancement in the field. The defects at the perovskite/carrier transport layer interface pose significant challenges to the performance of perovskite solar cells. Here, the authors introduce a dual host-guest complexation strategy with Cs-crown-ether and ammonium salt, achieving a high PCE of 25.9% with superior stability.

The systematic advances in the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs) have been driven by the developments of perovskite materials, electron transport layer (ETL) materials, and interfacial passivation between the relevant layers. While zinc oxide (ZnO) is a promising ETL in thin film photovoltaics, it is still highly desirable to develop novel synthetic methods that allow both fine‐tuning the versatility of ZnO nanomaterials and improving the ZnO/perovskite interface. Among various inorganic and organic additives, zwitterions have been effectively utilized to passivate the perovskite films. In this vein, we develop novel, well‐characterized betaine‐coated ZnO QDs and use them as an ETL in the planar n‐i‐p PSC architecture, combining the ZnO QDs‐based ETL with the ZnO/perovskite interface passivation by a series of ammonium halides (NH4X, where X = F, Cl, Br). The champion device with the NH4F passivation achieves one of the highest performances reported for ZnO‐based PSCs, exhibiting a maximum PCE of ~22% with a high fill factor of 80.3% and competitive stability, retaining ~78% of its initial PCE under 1 Sun illumination with maximum power tracking for 250 h.

Surface passivation has been widely employed to suppress non-radiative charge recombination and prevent interfacial charge accumulation in perovskite photovoltaics. In this report, carbazole modified with ammonium iodide connected via alkyl chains of different lengths (i.e., ethyl, butyl, and hexyl chains) is used to form passivation layers on formamidinium lead triiodide FAPbI3-based perovskite films to improve operational stability. Owing to the strong hydrophobicity of the carbazole moiety, it is observed that the perovskite films with a carbazole passivation layer retain their initial properties even after direct contact with a water droplet for 100 s. In addition, carbazole treatment reduces the rate of trap-assisted recombination at the surface and grain boundaries of the perovskite layer. Furthermore, it accelerates interfacial hole transfer from the perovskite to the charge transport layer. As a result, devices treated with carbazole hexylammonium iodide achieve a power conversion efficiency (PCE) of up to 24.3% during quasi-steady-state (QSS) measurements with extraordinary long-term operational stability under conditions of the ISOS-L-1 protocol, maintaining 95% of their initial efficiency after 1000 h. Surface passivation reduces non-radiative charge recombination and interfacial charge accumulation in perovskite photovoltaics. Carbazole, functionalized with ammonium iodide and alkyl chains, forms hydrophobic passivation layers on FAPbI3 perovskite films, improving stability and efficiency. This approach minimizes trap-assisted recombination and enhances hole transfer, achieving 24.8% PCE and maintaining 95% of its initial efficiency after 1000 h under the ISOS-L1 protocol. image

Perovskite solar cells (PSCs) have made great advances in terms of power conversion efficiency (PCE), yet their subpar stability continues to hinder their commercialization. The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs. In this work, we propose a strategy to stabilize high-performance PSCs with PCE over 23% by introducing a cesium-doped graphene oxide (GO-Cs) as an interlayer between the perovskite and hole-transporting material. The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80 (the time where the device PCE reduces to 80% of its initial value) of 2143 hours of operation at the maximum powering point under one sun illumination.

Efficient and robust n-i-p perovskite solar cells necessitate superior organic hole-transport materials with both mechanical and electronic prowess. Deciphering the structure-property relationship of these materials is crucial for practical perovskite solar cell applications. Through direct arylation, two high glass transition temperature molecular semiconductors, DBC-ETPA (202 °C) and TPE-ETPA (180 °C) are synthesized, using dibenzo[g,p]chrysene (DBC) and 1,1,2,2-tetraphenylethene (TPE) tetrabromides with triphenylene-ethylenedioxythiophene-dimethoxytriphenylamine (ETPA). In comparison to spiro-OMeTAD, both semiconductors exhibit shallower HOMO energy levels, resulting in increased hole densities (generated by air oxidation doping) and accelerated hole extraction from photoexcited perovskite. Experimental and theoretical studies highlight the more rigid DBC core, enhancing hole mobility due to reduced reorganization energy and lower energy disorder. Importantly, DBC-ETPA possesses a higher cohesive energy density, leading to lower ion diffusion coefficients and higher Young's moduli. Leveraging these attributes, DBC-ETPA is employed as the primary hole-transport layer component, yielding perovskite solar cells with an average efficiency of 24.5%, surpassing spiro-OMeTAD reference cells (24.0%). Furthermore, DBC-ETPA-based cells exhibit superior operational stability and 85 °C thermal storage stability.

Perovskite solar cells have led the new surge of solar energy research. However, their instability is a pressing issue mostly attributed to the perovskite interface with charge‐selective transport layers. In this work, diethylammonium iodide (DEAI) surface treatment is used to mitigate interfacial non‐radiative recombination losses by forming a mixed phase of layered perovskite on the surface. This results in enhanced device performance with the power conversion efficiency of 23.3% and improved operational stability under thermal stress. Moreover, the DEAI treatment facilitates interfacial hole transfer, enabling a carbon‐based hole transport layer‐free perovskite solar cell with a power conversion efficiency of 15.6%.

A myriad of studies and strategies have already been devoted to improving the stability of perovskite films; however, the role of the different perovskite crystal facets in stability is still unknown. Here, we reveal the underlying mechanisms of facet-dependent degradation of formamidinium lead iodide (FAPbI3) films. We show that the (100) facet is substantially more vulnerable to moisture-induced degradation than the (111) facet. With combined experimental and theoretical studies, the degradation mechanisms are revealed; a strong water adhesion following an elongated lead-iodine (Pb-I) bond distance is observed, which leads to a δ-phase transition on the (100) facet. Through engineering, a higher surface fraction of the (111) facet can be achieved, and the (111)-dominated crystalline FAPbI3 films show exceptional stability against moisture. Our findings elucidate unknown facet-dependent degradation mechanisms and kinetics.