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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Meta‐Analysis and Regression Modeling of the Impacts of Four Indoor Environmental Quality Metrics on Office Performance

Awareness of how buildings interact with the occupant experience—especially human performance—is becoming more prevalent, as seen by increasing interest and investment in healthy built environments. However, there is a need to synthesize the wide array of existing indoor environmental assessment and performance research in a way that can translate directly to building design and operation. Existing research in this area typically focuses on a single isolated metric and has not focused on making the results utilizable by building practitioners. The aim of this research is to investigate existing office performance literature through meta‐analyses and produce regression models for four indoor environmental quality (IEQ) metrics to support critical decision‐making for building operation and renovation. To reach this aim, a literature review was conducted to identify studies that measure the impact of changing ventilation rate, temperature, horizontal illuminance, and noise level in offices on occupant task performance. This repository of field and laboratory studies was analyzed to visualize the trends between the selected IEQ metrics and task performance. The temperature, ventilation rate, and horizontal illuminance regression models showed clear improvement potential when modifying indoor conditions toward the defined high‐performance range, while the regression model for noise level was inconclusive. The discussion notes the importance of designing holistically for all components of these IEQ categories to utilize the results, for example, good filtration on outdoor air for quantifying ventilation impact and uniform overhead lighting with low contrast for quantifying horizontal illuminance impact. The novelty of this work is in considering multiple facets of the indoor environment under a single, unified analysis schema and producing IEQ‐based performance gains that can directly inform cost‐benefit analyses of building design and renovation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Detailed mixing measurements from single-hole converging ECN injectors using Rayleigh scattering

Time resolved liquid and vapor fields of dodecane and oxymethylene ethers are measured from Spray A-3 and Spray D using high speed Rayleigh scattering and diffuse back illumination at the Engine Combustion Network (ECN) Spray A condition of 900 K and 22.8 kg/m 3 . Global quantities including mixture fraction, vapor and liquid penetration, as well as spreading angle are measured. The mixture fraction fields and vapor penetration profiles are well predicted by the 1-D Musculus-Kattke model. The mixture fraction field and vapor penetration from Spray A-3 are similar to those measured from Spray A in previous works. Spray D exhibits higher mixture fraction fields and vapor penetration due to its larger nozzle diameter. The quasi-steady mixture fraction fields from these injectors scale well when distance from the injector is normalized by the nozzle diameter. The turbulent dissipation structures were also analyzed based on the orientation, thickness, and magnitude of the mixing layers. Furthermore, the orientation and thickness are similar to other measurements in atmospheric gas jets, while the magnitude is lower. The thickness and magnitude are subject to uncertainties due to limitations in the imaging resolution of the system but still provide an order of magnitude as a useful reference for comparison against computational fluid dynamic simulations.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

Advanced Energy Design Guide for K-12 School Buildings (AEDG) Training: Cooperative Research and Development Final Report, CRADA Number CRD-18-00761

U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (BTO), Commercial Buildings Integration (CBI) Program supports the adoption of zero energy ready buildings design practices through targeted Science, Technology, Engineering, and Mathematics (STEM) workforce development. The National Renewable Energy Laboratory (NREL) identified the opportunity to provided targeted training to those professionals that have the greatest potential to impact adoption and successful design outcomes of zero energy ready buildings projects. In January 2018, ASHRAE released Achieving Zero Energy: Advanced Energy Design Guide for K-12 School Buildings (AEDG). The AEDG was developed in collaboration with NREL, American Institute of Architects (AIA), American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE), U.S. Green Building Council (USGBC), and Illuminating Engineers Society (IES). The purpose of this CRADA was to create a partnership between NREL, AIA, ASHRAE, USGBC, and IES to create and host on-demand, web-based training based on the AEDG.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Synechocystis sp. PCC 6803 Requires the Bidirectional Hydrogenase to Metabolize Glucose and Arginine Under Oxic Conditions

The cyanobacterium Synechocystis sp.PCC 6803 possesses a bidirectional NiFe-hydrogenase, HoxEFUYH. It functions to produce hydrogen under dark, fermentative conditions and photoproduces hydrogen when dark-adapted cells are illuminated. Unexpectedly, we found that the deletion of the large subunit of the hydrogenase (HoxH) in Synechocystis leads to an inability to grow on arginine and glucose under continuous light in the presence of oxygen. This is surprising, as the hydrogenase is an oxygen-sensitive enzyme. In wild-type (WT) cells, thylakoid membranes largely disappeared, cyanophycin accumulated, and the plastoquinone (PQ) pool was highly reduced, whereas ΔhoxH cells entered a dormant-like state and neither consumed glucose nor arginine at comparable rates to the WT. Hydrogen production was not traceable in the WT under these conditions. We tested and could show that the hydrogenase does not work as an oxidase on arginine and glucose but has an impact on the redox states of photosynthetic complexes in the presence of oxygen. It acts as an electron valve as an immediate response to the supply of arginine and glucose but supports the input of electrons from arginine and glucose oxidation into the photosynthetic electron chain in the long run, possibly via the NDH-1 complex. Despite the data presented in this study, the latter scenario requires further proof. The exact role of the hydrogenase in the presence of arginine and glucose remains unresolved. In addition, a unique feature of the hydrogenase is its ability to shift electrons between NAD(H), NADP(H), ferredoxin, and flavodoxin, which was recently shown in vitro and might be required for fine-tuning. Taken together, our data show that Synechocystis> depends on the hydrogenase to metabolize organic carbon and nitrogen in the presence of oxygen, which might be an explanation for its prevalence in aerobic cyanobacteria.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

All-optical photoluminescence response of nitrogen-vacancy ensembles in diamond at low magnetic fields

All-optical (AO) microwave-free magnetometry using nitrogen-vacancy (N-𝑉) centers in diamond is attractive due to its broad applicability and reduced experimental complexity. In this work, we investigate room-temperature AO photoluminescence (PL) at low magnetic fields ( <2 mT) using diamonds with N-𝑉 ensembles at parts-per-million (ppm) concentrations. The measured AO-PL contrast features as a function of the applied magnetic field magnitude and direction are correlated with near-degenerate N-𝑉 electronic spin and hyperfine transitions from different N-𝑉 orientations within the diamond host. Reasonable agreement is found between low-field AO-PL measurements and model-based simulations of the effects of resonant dipolar interactions between N-𝑉 centers. The maximum observed AO-PL contrast depends on both the N-𝑉 concentration and the laser-illumination intensity at 532 nm. These results imply different optimal conditions for low-field AO N-𝑉 sensing compared to conventional optically detected magnetic resonance (ODMR) techniques, suggesting new research and application opportunities using AO measurements with lower system complexity, size, weight, and power.

Dipolar interaction↗
DOE OSTI2020

Auxin‐induced actin cytoskeleton rearrangements require AUX1

Summary The actin cytoskeleton is required for cell expansion and implicated in cellular responses to the phytohormone auxin. However, the mechanisms that coordinate auxin signaling, cytoskeletal remodeling and cell expansion are poorly understood. Previous studies examined long‐term actin cytoskeleton responses to auxin, but plants respond to auxin within minutes. Before this work, an extracellular auxin receptor – rather than the auxin transporter AUXIN RESISTANT 1 (AUX1) – was considered to precede auxin‐induced cytoskeleton reorganization. In order to correlate actin array organization and dynamics with degree of cell expansion, quantitative imaging tools established baseline actin organization and illuminated individual filament behaviors in root epidermal cells under control conditions and after indole‐3‐acetic acid (IAA) application. We evaluated aux1 mutant actin organization responses to IAA and the membrane‐permeable auxin 1‐naphthylacetic acid (NAA). Cell length predicted actin organization and dynamics in control roots; short‐term IAA treatments stimulated denser and more parallel, longitudinal arrays by inducing filament unbundling within minutes. Although AUX1 is necessary for full actin rearrangements in response to auxin, cytoplasmic auxin (i.e. NAA) stimulated a lesser response. Actin filaments became more ‘organized’ after IAA stopped elongation, refuting the hypothesis that ‘more organized’ actin arrays universally correlate with rapid growth. Short‐term actin cytoskeleton response to auxin requires AUX1 and/or cytoplasmic auxin.

AUX1↗
DOE OSTI2022

Perovskite grain wrapping by converting interfaces and grain boundaries into robust and water-insoluble low-dimensional perovskites

Stabilizing perovskite solar cells requires consideration of all defective sites in the devices. Substantial efforts have been devoted to interfaces, while stabilization of grain boundaries received less attention. Here, we report on a molecule tributyl(methyl)phosphonium iodide (TPI), which can convert perovskite into a wide bandgap one-dimensional (1D) perovskite that is mechanically robust and water insoluble. Mixing TPI with perovskite precursor results in a wrapping of perovskite grains with both grain surfaces and grain boundaries converted into several nanometer-thick 1D perovskites during the grain formation process as observed by direct mapping. The grain wrapping passivates the grain boundaries, enhances their resistance to moisture, and reduces the iodine released during light soaking. The perovskite films with wrapped grains are more stable under heat and light. The best device with wrapped grains maintained 92.2% of its highest efficiency after light soaking under 1-sun illumination for 1900 hours at 55°C open-circuit condition.

14 SOLAR ENERGY↗
DOE OSTI2020

The effect of lighting environment on task performance in buildings – A review

The effects of indoor environmental conditions on human health, satisfaction, and performance have been the focal point of research for decades. This paper reviews and summarizes the impact of lighting environment on task performance, specifically for the built environment audience. Existing studies included a variety of performance tests on cognitive performance and perception, visual acuity and reaction, memory, reasoning, and labor productivity. Illuminance, luminance ratio and correlated color temperature were found to affect performance in different ways, reflecting the impact of experimental techniques, conditions, performance evaluation methods used and data analysis methods. These were reviewed and categorized, with discussion on limitations related to sample size, modeling approach, carryover effects and other factors affecting individual differences in performance, with recommendations for future improvement. Although no universal conclusions can be made, in general, task performance seems to improve with higher illuminances, contrast ratios in the range of 7–11:1 (while always making sure that glare will not occur in the space) and higher correlated color temperature, while spectral tuning in the red or blue wavelengths has also shown positive effects. To obtain more generic evidence, future studies should be more consistent in terms of experimental procedures and overall light conditions, and also consider the effects of vertical illuminance, daylight provision/control, and outside views on task performance. Finally, studying performance with multi-factorial designs in a human-centered optimized manner (such as deploying variable lighting scenarios optimized for various tasks) can lead to deeper understanding of lighting effects on task performance, and ultimately to improved lighting design and operation in buildings overall.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Irradiance on the upper and lower modules of a two-high bifacial tracking system

We examine the illumination incident to each of the modules in a two-high bifacial tracking photovoltaic system. Experiments and simulations indicate that the upper module receives more diffuse sunlight, whereas either the upper or lower module can receive more direct sunlight depending on the configuration and conditions. We use a view-factor model to illustrate how the fraction of illumination received by the upper and lower modules depends on albedo, the sun’s position in the sky, module tilt, and the fraction of direct sunlight. We also use ray tracing to illustrate how edge effects can significantly change the amount of sunlight reaching the upper and lower modules; these results underscore the complications of using measurements from small test facilities to predict the behavior of large PV fields.

McIntosh, Keith↗
DOE OSTI2024

Field‐representative evaluation of PID‐polarization in TOPCon PV modules by accelerated stress testing

Abstract Potential‐induced degradation‐polarization (PID‐p) can reduce module power, but how to project the extent to which PID‐p may occur in field conditions considering the factors of system voltage, condensed moisture, temperature, and illumination has not been clarified. Using tunnel oxide passivated contact (TOPCon) modules, this work demonstrates a method to test full‐size crystalline silicon PV modules for PID‐p to provide field‐representative results. In initial screening tests with positive or negative 1000 V electrical bias applied at 60°C for 96 h using Al foil electrodes on the glass surfaces, the module type exhibited reversible PID‐p only on the front face when the cell circuit was in negative voltage potential. No PID was detected on the rear after testing in either polarity. We then evaluated the PID‐p sensitivity on the front side under different UV irradiances while maintaining the glass surface wet to estimate real‐world susceptibility to PID‐p. The magnitude of the observed behavior was fit using a previously developed charge transfer and depletion by light model. Whereas power loss with −1000 V applied to the cell circuit at 60°C for 96 h in the dark was about 30%, testing the module front under 0.051 W·m −2 nm −1 at 340 nm UVA irradiation using fluorescent tubes, the mean degradation was only 3%. When the modules were tested in the dark for PID‐p with in situ dark current–voltage (I‐V) characterization, the thermal activation energy for degradation was 0.71 eV; for recovery in the dark, it was 0.58 eV. Whereas recovery from the degraded state at 60°C in the dark without voltage bias was 5% absolute in 38 h, rapid recovery of about 5% absolute was observed with 1000 W·s/m 2 exposure at 25°C using a flash tester.

14 SOLAR ENERGY↗
DOE OSTI2026

Catalytic resonance theory for the kinetic signatures of multiple wavelength photocatalysis

Multi-step surface chemistry promoted with one or two wavelengths of light exhibited distinct kinetic signatures indicative of the light-adsorbate interactions and the number of photon-sensitive elementary steps. In this work, kinetic Monte Carlo simulations identified the kinetic response of general surface mechanisms to variation in the per-site photon flux of one or two wavelengths of incident light. Photocatalytic rates were described via a non-dimensional photon flux, identifying multiple kinetic regimes with unique degrees of rate control. Under photon-controlled kinetic conditions, maximum quantum yield and turnover frequency were obtained under constant illumination, while pulsing of one or more light sources was shown to exhibit slower rates and less efficient photocatalytic promotion due to the inherent dynamic nature of light, which comprises a stream of photons. Simulations provided distinct kinetic signatures in catalytic rates and Arrhenius kinetics for specific light-surface-adsorbate interactions corresponding to photocatalytic promotion of specific steps in surface chemistry.

catalytic resonance↗
DOE OSTI2022

Impact of Solid State Roadway Lighting on Melatonin in Humans

Introduction: In 2009, the World Health Organization identified vehicle crashes, both injury-related and fatal, as a public health hazard. Roadway lighting has long been used to reduce crashes and improve the safety of all road users. Ocular light exposure at night can suppress melatonin levels in humans. At sufficient light levels, all visible light wavelengths can elicit this response, but melatonin suppression is maximally sensitive to visible short wavelength light. With the conversion of roadway lighting to solid state sources that have a greater short wavelength spectrum than traditional sources, there is a potential negative health impact through suppressed melatonin levels to roadway users and those living close to the roadway. This paper presents data on the impact of outdoor roadway lighting on salivary melatonin in three cohorts of participants: drivers, pedestrians, and those experiencing light trespass in their homes. Methods: In an outdoor naturalistic roadway environment, healthy participants (N = 29) each being assigned to a cohort of either pedestrian, driver, or light trespass experiment, were exposed to five different solid state light sources with differing spectral emissions and one no lighting condition. Salivary melatonin measurements were made under an average roadway luminance of 1.0 cd/m2 (IES RP-18 Roadway Lighting Requirements for expressway roads) with a corneal melanopic Equivalent Daylight Illuminances (EDI) ranging from 0.22 to 0.86 lux. Results: The results indicate that compared to the no roadway lighting condition, the roadway light source spectral content did not significantly impact salivary melatonin levels in the participants in any of the cohorts. Conclusions: These data show that recommended levels of street lighting for expressway roads do not elicit an acute suppression of salivary melatonin and suggest that the health benefit of roadway lighting for traffic safety is not compromised by an acute effect on salivary melatonin.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Building a Framework to Understand Transition Metals' Behavior in Euxinic Conditions (Final Technical Report)

This project focuses first and foremost on metal sulfide geochemistry and mineralogy as controlled by a complex matrix of environmental factors. The principal investigator’s group aim to illuminate the metal-sulfide reaction mechanisms, rates, and pathways through systematic experimentation and data collection and analyzing the relationships between the characteristics of the produced metal sulfide solid-phase/aqueous complexes and the environmental factors. This understanding is essential for obtaining a full picture of the complex cycling patterns of single or multi metal species in sulfidic environments ranging from deep-see basins, hydrothermal vents, inland seas, terrestrial water bodies, to engineered remediation systems. The specific goal of this past project was to illuminate the reaction mechanisms and kinetics of metal anions and sulfide in mixed metal cation-metal anion-sulfide systems under various aqueous conditions (which resembled a range of naturally occurring euxinic settings). For the period of this contract, we investigated the molybdenum-iron-sulfide system, with an emphasis on the conditions that caused solid phase formation. We focused on quantifying the mobility/sequestration of molybdenum under each experimental condition and identified the changes of valence states for each involved element (i.e., Mo, Fe, and S) in the precipitate. We also proposed pathways for the electron transfer that occurred in aqueous chemistry. The major analytical tools used for this study include UV-visible light spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and synchrotron-based X-ray absorption spectroscopy (access gained through facility proposals to the Canadian Light Source). The biggest finding of this project was that besides pH, the iron-sulfur chemistry has a dominant control of the thiolation kinetics and subsequent reduction of Mo(VI), which are likely prerequisites of molybdenum sequestration in anoxic conditions. The results have been written up as manuscript by the end of this project (see Phillips et al.). The experimental results of this project may be critical for advancing our understanding of (1) basic chemistry involving transition metals and reduced sulfur species, (2) the validity of certain geochemical proxies, and (3) the stability and evolution of euxinic geochemical environments. It is noted that the basic results obtained through this project also have implications for Mo-S cluster-based catalyst development in inorganic chemistry and materials sciences.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Thermal Disorder‐Induced Strain and Carrier Localization Activate Reverse Halide Segregation

The reversal of halide ions is studied under various conditions. However, the underlying mechanism of heat-induced reversal remains unclear. This work finds that dynamic disorder-induced localization of self-trapped polarons and thermal disorder-induced strain (TDIS) can be co-acting drivers of reverse segregation. Localization of polarons results in an order of magnitude decrease in excess carrier density (polaron population), causing a reduced impact of the light-induced strain (LIS – responsible for segregation) on the perovskite framework. Meanwhile, exposing the lattice to TDIS exceeding the LIS can eliminate the photoexcitation-induced strain gradient, as thermal fluctuations of the lattice can mask the LIS strain. Under continuous 0.1 W cm -2 illumination (upon segregation), the strain disorder is estimated to be 0.14%, while at 80 °C under dark conditions, the strain is 0.23%. However, in situ heating of the segregated film to 80 °C under continuous illumination (upon reversal) increases the total strain disorder to 0.25%, where TDIS is likely to have a dominant contribution. Therefore, the contribution of entropy to the system's free energy is likely to dominate, respectively. Various temperature-dependent in situ measurements and simulations further support the results. These findings highlight the importance of strain homogenization for designing stable perovskites under real-world operating conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Coincidence Anticipation Timing Responses with Head Tracking and Eye Tracking

Head tracking movements are common in interceptive tasks. The benefits of these movements are unclear. The purpose of this study was to compare coincidence anticipation timing (CAT) responses for a simulated approaching object when the eyes were used in tracking the object and when the head was used in tracking the object.A total of 29 subjects participated. A Bassin Anticipation Timer consisting of a track of sequentially illuminated lights was used to simulate an approaching object at velocities of 223 cm · s -1 to 894 cm · s -1 . Each velocity was used 10 times under 2 conditions. In one condition, subjects were told to turn the eyes with the stimulus. In the other condition, subjects viewed the stimulus through apertures and were told to turn the head with the stimulus. Subjects pushed a button to coincide with illumination of the final light on the track. Signed CAT errors, unsigned CAT errors, and variable CAT errors were compared between the head movement (HM) and eye movement (EM) conditions. No significant differences were noted for the signed errors (mean signed error at 894 cm · s -1 ; 10.3 ± 75.4 ms (HM), -16.1 ± 51.0 ms (EM). However, the unsigned and variable errors were significantly larger at some stimulus velocities in the head movement condition [mean unsigned error at 894 cm · s -1 : 82.6.0 ± 45.9 ms (HM), 59.0 ± 22.4 ms (EM); mean variable error at 894 cm · s -1 ; 78.0 ± 37.8 ms (HM), 49.2 ± 17.1ms (EM)]. DISCUSSION: Head movement did not result in improved CAT performance compared to eye movements. Further work will be required to determine whether these results are generalizable to situations where head tracking is required but apertures are not worn.

Biophysics↗
DOE OSTI2023

Modulation of xanthophyll cycle impacts biomass productivity in the marine microalga Nannochloropsis

Life on earth depends on photosynthetic primary producers that exploit sunlight to fix CO 2 into biomass. Approximately half of global primary production is associated with microalgae living in aquatic environments. Microalgae also represent a promising source of biomass to complement crop cultivation, and they could contribute to the development of a more sustainable bioeconomy. Photosynthetic organisms evolved multiple mechanisms involved in the regulation of photosynthesis to respond to highly variable environmental conditions. While essential to avoid photodamage, regulation of photosynthesis results in dissipation of absorbed light energy, generating a complex trade-off between protection from stress and light-use efficiency. This work investigates the impact of the xanthophyll cycle, the light-induced reversible conversion of violaxanthin into zeaxanthin, on the protection from excess light and on biomass productivity in the marine microalgae of the genus Nannochloropsis. Zeaxanthin is shown to have an essential role in protection from excess light, contributing to the induction of nonphotochemical quenching and scavenging of reactive oxygen species. On the contrary, the overexpression of zeaxanthin epoxidase enables a faster reconversion of zeaxanthin to violaxanthin that is shown to be advantageous for biomass productivity in dense cultures in photobioreactors. These results demonstrate that zeaxanthin accumulation is critical to respond to strong illumination, but it may lead to unnecessary energy losses in light-limiting conditions and accelerating its reconversion to violaxanthin provides an advantage for biomass productivity in microalgae.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Understanding the Stability of Etched or Platinized p-GaInP Photocathodes for Solar-Driven H 2 Evolution

The long-term stability in acidic or alkaline aqueous electrolytes of p-Ga 0.52 In 0.48 P photocathodes, with a band gap of ~1.8 eV, for the solar-driven hydrogen-evolution reaction (HER) has been evaluated from a thermodynamic, kinetic, and mechanistic perspective. At either pH 0 or pH 14, etched p-GaInP electrodes corroded cathodically under illumination and formed metallic In 0 on the photoelectrode surface. In contrast, under the same conditions, electrodeposition of Pt facilitated the HER kinetics and stabilized p-GaInP/Pt photoelectrodes against such cathodic decomposition. When held at 0 V versus the reversible hydrogen electrode, p-GaInP/Pt electrodes in either pH = 0 or pH = 14 exhibited stable current densities (J) of ~-9 mA cm -2 for hundreds of hours under simulated 1 sun illumination. During the stability tests, the current density-potential (J-E) characteristics of the p-GaInP/Pt photoelectrodes degraded due to pH-dependent changes in the surface chemistry of the photocathode. This work provides a fundamental understanding of the stability and corrosion mechanisms of p-GaInP photocathodes that constitute a promising top light absorber for tandem solar-fuel generators.

14 SOLAR ENERGY↗
DOE OSTI2025

Ionic liquids improve the long-term stability of perovskite solar cells

Achieving operational stability in halide perovskite solar cells remains a critical challenge for commercialization. Ionic liquids are promising bulk modifiers, yet their mechanistic role in perovskite crystallization is poorly understood. Here we engineered an ionic liquid, methoxyethoxymethyl-1-methylimidazole chloride (MEM-MIM-Cl), with an ethylene glycol ether side chain that regulates perovskite growth and stabilizes buried interfaces via synergistic interactions with NiO x . MEM-MIM-Cl induces a novel intermediate phase through chelation with undercoordinated Pb(II), suppressing defects and defect-induced degradation. Solar cells incorporating MEM-MIM-Cl achieved a power conversion efficiency of 25.9% and retained 90% of their initial performance after 1,500 h under continuous 1-sun illumination and 90 °C thermal stress—surpassing prior benchmarks under milder ageing conditions. Furthermore, diurnal cyclic ageing revealed unprecedented fatigue resistance, highlighting the dual role of MEM-MIM-Cl in simultaneously enhancing efficiency and operational resilience. In conclusion, this work elucidates design principles for functional ionic liquids while advancing perovskite photovoltaics towards industrial viability.

14 SOLAR ENERGY↗