Michaël Grätzel

Hierarchical Flux Competition Governs Electrochemical‐Chemical Coupling in Redox‐Mediated Batteries

Experimental analysis reveals a kinetic flux framework for redox-mediated batteries, indicating that balanced competing transport steps enhance energy density and cyclability.

PFN‐Br Modified Buried Interface Enhanced Charge Extraction in Inverted Wide‐Bandgap Perovskite Solar Cells

Evaluates PFN-Br impact on hole extraction in wide-bandgap perovskite solar cells, indicating improved energy efficiency.

Quantifying Deep‐Level Defects‐Dominated Degradation for Commercially Viable Perovskite Solar Cells

Identifies deep-level defects causing degradation in perovskite solar cells, suggesting enhanced stability and efficiency.

Mn and Au redox mediators in ZnCl₂ water-in-salt electrolytes: Implications for Zn-ion battery chemistry

• The Mn-electrochemistry in WiSE is free from the issue of “dead MnO₂” • Au rapidly oxidizes in WiSE to AuCl₄⁻, the dissolution rate is ca. twice that of Zn • The electrochemistry of AuCl 4 - closely parallels that of Mn 2+ in WiSE • The areal capacity of ∼1 mAh/cm 2 is achieved in tens of cycles • Oxidation of Mn 2+ yields reversibly cyclable γ-MnO 2 as the main product 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: MnCl 2 and HAuCl 4 dissolved in 15 m ZnCl 2 . 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 MnO 2 ” problem, while γ-MnO 2 is generated by anodic oxidation of Mn 2+ 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 Zn 2+ /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(NH 3 ) 6 3+/2+ couple, which is essentially insensitive to ZnCl 2 concentration. Gold undergoes rapid oxidative dissolution to AuCl 4 - . 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 energy-storage systems with WiSE.

Surface-Only Nuclear Magnetic Resonance Spectroscopy by Dynamic Nuclear Polarization and ² H-Dephasing

Scaling Low Temperature CO2-to-Syngas Electroreduction: Insights into Engineering Bottlenecks and Mitigation Strategies

This review identifies challenges in CO2 electroreduction for syngas, suggesting strategies for efficient commercialization.

Molecular-level understandings and device strategies for FAPbI₃-based perovskite solar cells

Investigation reveals how chemical bonding influences optoelectronic properties in perovskite solar cells, suggesting improved device stability.

Electrolyte effects and stability of Zn/Li dual-ion batteries with water-in-salt electrolytes

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 LiFePO 4 as a positive electrode, revealing a redox potential of 1.17 V vs. Zn 2+ /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 LiMnPO 4 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.

Spiro‐Phenothiazine Hole‐Transporting Materials: Unlocking Stability and Scalability in Perovskite Solar Cells

Improving both the efficiency and long‐term stability of perovskite solar cells (PSCs) is critical for their commercial deployment. Despite the widespread use of spiro‐OMeTAD as a hole‐transporting material (HTM), its inhomogeneous doping behavior and susceptibility to moisture and heat have hindered its large‐scale industrial implementation. Here, a family of spiro‐phenothiazine‐based HTMs (PTZ) is reported to address these drawbacks. Among them, the fluorene derivative (PTZ‐Fl) shows a larger Li + affinity and forms a compact interphase by intercalation in the perovskite passivating layer that prevents Li + migration. PSCs incorporating PTZ‐Fl exhibit power conversion efficiencies (PCEs) up to 25.8% (certified 25.2% under reverse scan), retaining 80% of their initial performance after 1000 h under ISOS‐L‐3 protocol. Furthermore, a 5 × 5 cm mini‐module reaches a PCE of 22.1%, surpassing spiro‐OMeTAD‐based PSCs and retaining over 85% of its efficiency after 1100 h under ISOS‐D‐1 protocol. These results demonstrate that PTZ‐Fl not only enables high PCEs but also substantially improves operational stability, offering a promising pathway toward the large‐scale deployment of next‐generation PSCs.

Designing multi-metal-site nanosheet catalysts for CO2 photoreduction to ethylene

Catalysts featuring multiple active sites hold significant potential for CO 2 photoconversion to multi-carbon products. However, multi-metal-site catalysts typically face challenges with low yields and selectivity for ethylene production, with a lack of definitive design guidelines. Here we show that Bader charge can serve as a critical descriptor for delineating the structure–activity relationship of kesterite-like nanosheets in the reduction of CO 2 to ethylene. We propose the Bader-Regulate-Performance principle — apposite Bader charge can provide a moderate energy barrier for intermediate adsorption and C-C coupling simultaneously, thus promoting the performance for ethylene generation. Among the predicted multi-metal-site nanosheets, the Cu 2 ZnSnS 4 , with the appropriate Bader charge, achieves a high ethylene yield of 25.16 µmol g −1 h −1 with electron selectivity of 72.4% under visible light irradiation, surpassing those of reported photocatalysts under similar catalytic conditions. Our findings provide crucial insights into the design of efficient catalysts for photocatalytic CO 2 conversion to multi-carbon products.

Synergistic Electron-Deficient Surface Engineering: A Key Factor in Dictating Electron Carrier Extraction for Perovskite Photovoltaics

Experimental study demonstrates enhanced electron extraction in perovskite solar cells, indicating molecular electronic properties dominate over dipole orientation.

Dopamine Dopes the Performance of Perovskite Solar Cells

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 SnO 2 film, whose catechol moiety adheres strongly to the SnO 2 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.

TEMPO bulk passivation boosts the performance and operational stability of rapid-annealed FAPI perovskite solar cells

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.

Silver Bismuth Iodides for Photovoltaic Applications: Insights from Ab Initio Calculations and Experimental Analysis

Hybrid organic–inorganic perovskite solar cells (PSCs) present a leading thin-film photovoltaic technology with superior solar-to-electric power conversion efficiencies. The most effective compositions, however, contain lead cations, which are toxic and pose environmental hazards. One of the alternatives to lead-based perovskite materials is silver bismuth halide analogues. Here, we present a comprehensive investigation of different silver bismuth iodide compositions by means of density functional theory calculations (DFT) as well as X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy measurements. Through our combined experimental and theoretical study, we have discovered that silver bismuth iodides possess several intrinsic limitations, such as limited charge transport and localized electronic states, owing to the presence of vacant sites. Such limitations result in moderate solar cell efficiencies, significantly lower than those of lead halide perovskites. However, we suggest the possibility of increasing efficiencies by adding BiCl 3 to the precursor solution, yielding one of the highest efficiencies reported for this class of compounds to date. This highlights the potential of compositional engineering for these lead-free solar cell materials.

Enhancing Indoor Photovoltaic Efficiency to 37.6% Through Triple Passivation Reassembly and n‐Type to p‐Type Modulation in Wide Bandgap Perovskites

Despite well‐matching indoor illumination spectra, the performance of wide bandgap perovskite solar cells (WB‐PSCs) for indoor photovoltaics (i‐PV) is hindered by photo‐induced halide phase segregation and trap‐assisted non‐radiative recombination. Herein, a Triple Passivation Treatment (TPT) reassembly strategy is presented to simultaneously suppress bulk and surface defects. TPT induces a transition in perovskite surface energetics from n ‐type to p ‐type and remarkably increases the photoluminescence quantum yield from 0.5 to 2.1%, creating a more favorable band alignment for hole extraction whilst substantially reducing halide phase segregation. As a result, 1.75 eV WB‐PSCs achieve an indoor Power Conversion Efficiency (iPCE) of 37.6% under 1000 lux illumination. Under standard sunlight conditions, the devices reach a Power Conversion Efficiency (PCE) of 20.1% and a fill factor of 78.5%, among the best performance parameters for this bandgap. Importantly, the passivated devices exhibit excellent shelf stability, retaining 92% of their initial performance after 3200 h. Under ambient air conditions at 55 °C, the unencapsulated devices maintained 76% of their initial PCE after 300 h continuous light soaking. The findings represent a significant breakthrough in the development of stable WB‐PSCs for i‐PV applications, with minimized nonradiative losses and enhanced performance.

Electrochemical co-upgrading CO ₂ and glycerol for selective formate production with 190% overall Faradaic efficiency

The overall energy efficiency (EE) is critical for commercializing promising electrochemical technologies, such as the carbon dioxide reduction reaction (CO₂RR). Despite the rapid development of advanced catalysts and reactors for CO₂RR, its commercial potential is still hindered by the sluggish oxygen evolution reaction (OER), which causes high cell voltages and low EEs. Herein, we developed a NiOOH@Ni₃S₂ catalyst on the surface of nickel foam (NF) via an electrochemical surface reconstruction strategy. We observed that the oxidation of glycerol (GLY) to formate (FA) is more thermodynamically favorable than the OER on the developed NiOOH@Ni₃S₂/NF catalysts. The Ni²⁺/Ni³⁺ redox couples within the NiOOH@Ni₃S₂ heterojunction enhance the charge transfer kinetics between the active sites and adsorbed reaction intermediates, facilitating the highly selective and active generation of FA from GLY oxidation reaction (GOR), with a remarkable Faradaic efficiency (FE) of 94% achieved at 100 mA·cm⁻². Comprehensive mechanistic studies identified that the reaction pathway towards FA generation starts from glyceraldehyde intermediates, and glycolate was considered as the key species. Moreover, benefiting from the efficient conversion of CO₂ to FA on bismuth nanosheets, the GOR//CO₂RR paired electrolysis system realizes a remarkable overall FE of ca. 190% for FA co-production at 160 mA·cm⁻² (cathodic FE: 91.25% and anodic FE: 98.70%). This proceeds at a cell voltage of ca. 2.32 V, which is ca. 0.85 V lower than that of OER-assisted CO₂RR system at the same current density. This work provides new insights for co-upgrading CO₂ and biomass to value-added chemicals.

Dipolar Carbazole Ammonium for Broadened Electric Field Distribution in High-Performance 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 PDAI 2 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).

Cuprous oxide-Shewanella mediated photolytic hydrogen evolution

Hydrogen could be an environmentally friendly option as an energy vector for the future. However, its green production process is expensive, involving water electrolysis, which requires a significant amount of energy. New technologies have been developed to decrease the cost associated with water electrolysis, such as using microbial electrolysis cells (MECs). The integration of power performance enhancing elements into bioelectric systems is of applied interest. As in this work the integration of a photocathode into the microbial electrolysis cell, the energy output increases in theory without needing more reactor space. The microbial electrolysis process requires an additional energy input to overcome the theoretical thermodynamic barrier if any and the involved overpotentials for reasonable rate of hydrogen production. In this work, a microbial electrolysis half-cell was combined with a photoelectrochemical half-cell, so called MPEC (microbial photoelectrochemical cell). The MPEC consisted of a Shewanella oneidensis MR-1 bioanode and a five-layered p-type Cu 2 O-based photocathode, using lactate as electron donor to produce H 2 without any external bias than light of 210 and 700 W m −2 . The novelty of the work can be summarized in the following points: The use of MPEC for H 2 production with a stable and efficient multilayer Cu 2 O photocathode. The quantification of the anodic, cathodic and global coulombic efficiencies considering the selectivity of lactate to acetate conversion. The electrochemical characterization (I–V curves) of the bioanode and photocathode for the determination of the electrode which limit the current in the process. Proposition of a model to explain the low anodic coulombic efficiencies (7 ± 2%). In this model lactate may be involved in either a surface reaction at the bioanode (the main reaction producing current) or a bulk aerobic or anaerobic reaction catalysed by planktonic cells (a side reaction that consumes lactate without producing current). This work is of interest of research that aims to integrate multiple processes into bioelectric systems and to use light energy in a direct manner to generate energy vectors such as hydrogen. • A Shewanella oneidensis anode and Cu 2 O-photocathode were employed in an MPEC. • Hydrogen was produced at varying light intensities without an external bias. • During MPEC processing, the coulombic efficiencies were determined. • A model explains two kind of lactate oxidation and eventual efficiency losses.

Solar photons beyond the band gap wavelengths: their effect on solution-processed solar cells

) on operating temperature and power conversion efficiency (PCE) losses, highlighting the conditions, materials, and optimal architectures for reducing device temperature. These improvements could reduce PCE losses by up to ∼7 times compared to conventional silicon wafer-based solar cells in real-world conditions.

Unlocking high-performance photocapacitors for edge computing in low-light environments

Integrating dye-sensitized solar cells with polyviologen-based supercapacitors enables efficient ambient light harvesting and storage, achieving 30% power conversion efficiency under indoor lighting conditions to power edge computing IoT networks.