ACS Energy Letters 最新文献

This study explores the ionic dynamics in 2D/3D perovskite solar cells, which are known for their improved efficiency and stability. The focus is on the impact of halide choice in 3D perovskites treated with phenethylammonium halide salts (PEAX, X = Br and I). Our findings reveal that light and heat drive ionic migration in these structures, with PEA⁺ species diffusing into the 3D film in PEABr-treated samples. Mixed-halide 3D perovskites show halide interdiffusion, with bromine migrating to the surface and iodine diffusing into the film. Cathodoluminescence microscopy reveals localized 2D phases on the 3D perovskite, which become more evenly distributed after thermal treatment. Both PEAX salts enhance the performance of photovoltaic devices. This improvement is attributed to the passivation capabilities of the salts themselves and their respective Ruddlesden−Popper (RP) phases. Annealed PEAI-treated devices show a better balance between efficiency and statistical distribution of photovoltaic parameters.

Drawing from both experimental data and simulation, we highlight best practices for fitting time-resolved photoluminescence (TRPL) decays of halide perovskite semiconductors, which are now widely studied for applications in photovoltaics and light-emitting diodes (LEDs). First, at low excitation intensities, high-quality perovskites often show pseudo-first-order kinetics, consistent with classic minority carrier lifetimes. Second, multiexponential decays, frequently observed at low excitation intensities, often have significant contributions from spatial heterogeneity. We recommend fitting such decays with stretched exponentials, where the stretching factor (β) can be used to characterize the heterogeneity of the local lifetime distribution. Third, PL decay kinetics can depend on the excitation wavelength. We discuss how penetration depth, carrier diffusion, and surface recombination affect measurements and make recommendations for choosing experimental parameters suited to the question at hand. Accounting for these factors will provide a more reliable and physical interpretation of carrier recombination and better understanding of nonradiative losses in perovskite semiconductors.

Materials-based H₂ storage plays a critical role in facilitating H₂ as a low-carbon energy carrier, but there remains limited guidance on the technical performance necessary for specific applications. Metal–organic framework (MOF) adsorbents have shown potential in power applications, but need to demonstrate economic promises against incumbent compressed H₂ storage. Herein, we evaluate the potential impact of material properties, charge/discharge patterns, and propose targets for MOFs’ deployment in long-duration energy storage applications including backup, load optimization, and hybrid power. We find that state-of-the-art MOF could outperform cryogenic storage and 350 bar compressed storage in applications requiring ≤8 cycles per year, but need ≥5 g/L increase in uptake to be cost-competitive for applications that require ≥30 cycles per year. Existing challenges include manufacturing at scale and quantifying the economic value of lower-pressure storage. Lastly, future research needs are identified including integrating thermodynamic effects and degradation mechanisms.

Cobalt-free lithium nickel oxide (LNO) has garnered significant interest as the end member of high-nickel layered oxide cathodes for next-generation batteries. However, its practical performance notably underperforms expectations because of the structural degradation and unstable interfacial chemistry with electrolytes during cycling. Here, we report that a durable cathode-electrolyte interface (CEI), enriched by in situ formed sulfides and borides, can inhibit LNO structural degradation and suppress Ni ion dissolution. With the CEI protection, the stability of LNO can be remarkably extended, and batteries demonstrate a capacity retention rate of 84% (30 °C) and 79% (50 °C) after 200 cycles at 1C, respectively. These results demonstrate that enriching CEI with sulfur-containing species can effectively stabilize the interfacial chemistry of LNO, particularly at an elevated temperature of 50 °C. This finding provides valuable perspectives on designing electrolytes for cobalt-free LNO and other high-Ni cathodes toward the development of next-generation high-energy-density lithium-ion batteries.

In metal halide perovskites, the complex dielectric screening together with low energy of phonon modes leads to non-negligible Fröhlich coupling. While this feature of perovskites has already been used to explain some of the puzzling aspects of carrier transport in these materials, the possible impact of polaronic effects on the optical response, especially excitonic properties, is much less explored. Here, with the use of magneto-optical spectroscopy, we revealed the non-hydrogenic character of the excitons in metal halide perovskites, resulting from the pronounced Fröhlich coupling. Our results can be well described by the polaronic-exciton picture where electron and hole interactions are no longer described by a Coulomb potential. Furthermore, we show experimental evidence that the carrier-phonon interaction leads to the enhancement of the carrier’s effective mass. Notably, our measurements reveal a pronounced temperature dependence of the carrier’s effective mass, which we attribute to a band structure renormalization induced by the population of low-energy phonon modes. This interpretation finds support in our first-principles calculations.

Magnesium (Mg) anodes typically experience electrochemical passivation and dendrite formation with conventional electrolytes during cell storage and operation, which results in a rapid decline in cyclability and shortened lifespans. These concerns supposedly relate to the features of the Mg/electrolyte interface. Herein, we report that Mg(BH₄)₂-rich artificial hybrid interphase (AHI) fabricated on Mg by a simple cation replacement method effectively ensures electrochemical activity and nondendritic interface. This can be attributed to the synergy of fast Mg²⁺ transfer, high electronically insulating and structural stability, etc., of AHI, as revealed by experimental and computational findings. The symmetric cell presents a low-voltage polarization of 230 mV and prolonged cycling life of over 1300 h at 1 mA cm^–2 in 0.5 M Mg[bis(trifluoromethanesulfonyl)imide (TFSI)]₂/dimethoxyethane (DME) electrolyte. Meanwhile, the full cells paired with a Mo₆S₈ cathode at various rates with desirable stability are also achieved. Our work provides further insight into the design of a versatile non-MgCl₂ artificial layer specialized for rechargeable Mg batteries.

The presence of the detrimental PbI₂ residue at the buried interface negatively affects the photovoltaic performance of perovskite solar cells (PSCs). However, the underlying mechanism involved in the formation and elimination of residual PbI₂ has been rarely investigated, despite its critical significance for high-efficiency and stable PSCs. Here, we investigated the formation and elimination mechanism of residual PbI₂ at the buried interface influenced by citric acid (CA) and found that CA can quickly remove the PbI₂·DMSO complex through a competitive adsorption mechanism by forming highly crystallized PbI₂. This promotes the subsequent intercalation of amine cations into the PbI₂ framework by forming a stable perovskite. Consequently, the best-performing target PSC achieves an efficiency of 25.19% (a certified efficiency of 24.64%) and 23% from a 1 cm² PSC. Additionally, the target PSC also demonstrates improved light stability after 200 h of UV light soaking by maintaining 94.21% of its initial efficiency compared with only 70.76% for the control PSC.

The droplet triboelectric nanogenerator (D-TENG) converts mechanical energy into electricity through contact electrification and electrostatic induction at the liquid–solid interface. The device’s efficiency is significantly influenced by the surface molecular structure of its triboelectric layer. By applying a fluorosilane surface modification, we enhanced the contact electrification sites and improved electron transfer between water molecules and the triboelectric layer, leading to a high-performance D-TENG. This modification allowed the surface potential of modified PTFE to reach 85% of its maximum with just five droplets, generating maximum charges of 80 and 500 nC with deionized and tap water droplets, respectively. These results surpass those of similar energy harvesting devices. The successful electron transfer mechanism was confirmed through first-principles and molecular dynamics, suggesting our approach could be broadly applicable to improving other triboelectric nanogenerators.

Light-emitting diodes (LEDs) with different emission spectra are widely used in daily life for a variety of applications. However, due to fundamental restrictions of light-emitting materials, the development of near-infrared LEDs (NIR-LEDs) is still modest. Recently, solution-processed tin-halide perovskites (THPs) have emerged as one of the most promising light-emitting materials for NIR-LED applications. In this Perspective, we start with discussing the peculiarities of THP semiconductors and how their electronic properties affect the light emission efficiency. We then summarize the current efforts in material engineering to design and master the electronic properties of THP films. Finally we give an outlook on the future challenges and technical roadmap for tin-based perovskite LEDs.