ACS Energy Letters 最新文献

All-perovskite tandem solar cells represent a significant advancement in next-generation photovoltaics toward higher power conversion efficiencies than single junction cells. A critical component of a monolithic tandem solar cell is the interconnecting layer, which facilitates the integration of the wide bandgap and low bandgap subcells. Conventional designs in all-perovskite tandem cells are based on an ultrathin metal recombination layer, typically Au, alongside a poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) hole transporting layer, which introduce optical and recombination losses, and instabilities. Here, we present a new interconnecting layer based on a graphene-oxide recombination layer, which facilitates the replacement of PEDOT:PSS with the preferred self-assembled monolayer [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz). This device architecture results in significantly reduced optical and nonradiative losses, leading to champion device efficiency of 23.4% compared to 19.7% with the conventional layers, along with improvements in stability. This work solves a critical challenge in all-perovskite tandem cell device design.

CsPb₂Br₅ single crystals (SCs) are promising for X-ray detection due to their high absorption, excellent photoelectric properties, and stability. However, thermal stress in high-temperature environments accelerates ion migration within perovskite structures, leading to degraded performance. In this study, we investigate the effects of Cr³⁺ doping, which induces lattice contraction and distortion due to its small ionic radius and strong electrophilic properties. This increases the formation energy of Br vacancies and activation energy for ion migration, enhancing the crystal’s resistance to thermal stress. As a result, Cr-doped CsPb₂Br₅ exhibits a high μτ value of 5.46 × 10^–3 cm² V^–1, a lower temperature coefficient of resistance (−1.58 × 10^–2 °C^–1), and excellent ion migration resistance at 70 °C. These improvements lead to a high sensitivity of 7183.5 μC Gy_air^–1 cm^–2 and a low detection dose rate of 11.5 nGy_air s^–1, with stable performance in X-ray imaging at elevated temperatures, making it suitable for complex environments.

Recent developments in “water-in-salt” electrolytes have precipitated a renewed effort to study imide-based electrolytes. While previous small-/wide-angle X-ray scattering (SAXS/WAXS) studies have attributed the emergence of a low-Q peak in the SAXS profile of aqueous LiTFSI electrolytes to nanometer-scale anion clustering, a molecular-level understanding of the root of these clusters remains unclear. In this study, we combined molecular dynamics simulations and SAXS/WAXS to study the solvation structures of LiTFSI in acetonitrile, methanol, and water. We concluded that hydrogen bonding in water and MeOH stabilizes anion clusters, while nonpolar methyl groups on methanol and acetonitrile interrupt the nanoscale ordering of TFSI anions. This causes LiTFSI in water and MeOH electrolytes to exhibit two low-Q SAXS profile peaks while LiTFSI in acetonitrile exhibits only a single peak below Q = 1 Å^–1. These findings shed light on the underlying molecular origins of nanoscale anion clusters, which may help in the design of the next generation of electrolyte chemistries.

The role of dynamically generated vacancies associated with cation migrations in activating or facilitating the anion redox reaction (ARR) in layered oxides is still unknown. By taking P2-type Na_2/3Zn_xMn_1–xO₂ as a model system, we herein showcase that Zn-migration induced vacancies are responsible for the ARR activity through first-principles calculations. Remarkably, we reveal a quasi-quantitative connection between Zn-migration induced vacancies and ARR activity in a series of Na_2/3Zn_xMn_1–xO₂ (x = 0.1–0.3) materials by an arsenal of characterizations. The partially reversible Zn migration will divide the ARR beyond the activation cycle into “reversible ion-migration induced” and “irreversible ion-migration induced” types. We further highlight that a stable cyclic performance can be achieved via balancing these two types of ARR and transition-metal (TM) redox, securing both a high reversible capacity and stable discharge voltage. These insights represent a conceptual breakthrough toward the role of dynamically generated vacancies in activating and stabilizing ARR.