Publications by authors named "J E Flege"
Ultrathin atomic layer deposited ceria films (< 20 nm) are capable of H2 heterolytic activation at room temperature, undergoing a significant reduction regardless of the absolute pressure, as measured under in-situ conditions by near ambient pressure X-ray photoelectron spectroscopy. ALD-ceria can gradually reduce as a function of H2 concentration under H2/O2 environments, especially for diluted mixtures below 10%. At room temperature, this reduction is limited to the surface region, where the hydroxylation of the ceria surface induces a charge transfer towards the ceria matrix, reducing Ce4+ cations to Ce3+.
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- The study investigates how low-temperature atomic layer deposited alumina (ALD-AlO) affects hybrid perovskites and their solar cell efficiency and stability.
- ALD-AlO enhances charge transfer and lifetime of perovskite solar cells (PSCs) due to its intrinsic defect states and also prevents mobile ion migration, which helps reduce current-voltage hysteresis.
- This method is cost-effective, quick, and compatible with solar cell technology, making it a promising solution for boosting PSC performance and marketability.
Reaction Dynamics between Formamidinium Lead Iodide and Copper Oxide.
ACS Appl Mater Interfaces
October 2024
Article Synopsis
- *The study investigated the impact of different CuO oxidation states and preparation methods on the degradation of FAPI, noting changes in reaction products as the temperature increased.
- *An attempt to mitigate CuO diffusion with an AlO layer only partially succeeded, highlighting the need for new methods to prevent chemical reactions that degrade the FAPI film in solar cell applications.
Understanding the interactions in hybrid systems based on graphene and functional oxides is crucial to the applicability of graphene in real devices. Here, we present a study of the structural defects occurring on graphene during the early stages of the growth of CoO, tailored by the electronic coupling between graphene and the substrate in which it is supported: as received pristine graphene on polycrystalline copper (coupled), cleaned in ultra-high vacuum conditions to remove oxygen contamination, and graphene transferred to SiO/Si substrates (decoupled). The CoO growth was performed at room temperature by thermal evaporation of metallic Co under a molecular oxygen atmosphere, and the early stages of the growth were investigated.
View Article and Find Full Text PDFCopper oxide appears to be a promising candidate for a hole transport layer (HTL) in emerging perovskite solar cells. Reasons for this are its good optical and electrical properties, cost-effectiveness, and high stability. However, is this really the case? In this study, we demonstrate that copper oxide, synthesized by a spray-coating method, is unstable in contact with formamidinium lead triiodide (FAPI) perovskite, leading to its decomposition.
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