| 1. |
- Comparotto, Corrado, et al.
(författare)
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Chalcogenide Perovskite BaZrS3 : Thin Film Growth by Sputtering and Rapid Thermal Processing
- 2020
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 3:3, s. 2762-2770
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Tidskriftsartikel (refereegranskat)abstract
- Tandem solar cells based on hybrid organic-inorganic metal halide perovskites have reached efficiencies up to 28%, but major concerns for long-term stability and the presence of Pb have raised interest in searching for fully earth-abundant, intrinsic chemically stable, and nontoxic alternatives. With a direct band gap around 1.8 eV and stability in air up to at least 500 degrees C, BaZrS3 is a promising candidate. This work presents the first approach of synthesizing a thin film of such compound by sputtering at ambient temperature with a subsequent rapid thermal process. Despite the short fabrication time, the width of the XRD diffraction peaks and the energy and distribution of the photoluminescence response show comparable crystalline quality to that from bulk synthesis methods. Good crystallization required around 900 degrees C. Such a high temperature could be incompatible with fabrication of tandem solar cells.
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| 2. |
- Comparotto, Corrado, et al.
(författare)
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Synthesis of BaZrS3 Perovskite Thin Films at a Moderate Temperature on Conductive Substrates
- 2022
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 5:5, s. 6335-6343
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Tidskriftsartikel (refereegranskat)abstract
- Chalcogenide perovskites are being considered for various energy conversion applications, not least photovoltaics. BaZrS3 stands out for its highly stable, earth-abundant, and nontoxic nature. It exhibits a very strong light-matter interaction and an ideal band gap for a top subcell in a two-junction photovoltaic device. So far, thin-film synthesis-necessary for proper optoelectronic characterization as well as device integration-remains underdeveloped. Sputtering has been considered, among others, but the need for an annealing step of at least 900 degrees C has been a cause for concern: such a high temperature could lead to damaging the bottom layers of prospective tandem devices. Still, a solid-state fabrication route has already demonstrated that BaZrS3 can form at much lower temperatures if excess S is present. In this work, sputtered Ba-Zr precursors capped by SnS are sulfurized at under 600 degrees C for 20 min. Although some Sn is still present at the surface after sulfurization, the resulting crystalline quality is comparable to samples synthesized at much higher temperatures. The results are rationalized, and the effect of key process variables is examined. This study represents the first successful synthesis of BaZrS3 perovskite that is compatible with conductive substrates-an important step forward for device integration.
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| 3. |
- Jacobo-Martin, Alejandra, et al.
(författare)
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Resilient moth-eye nanoimprinted antireflective and self-cleaning TiO2 sputter-coated PMMA films
- 2022
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 585
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Tidskriftsartikel (refereegranskat)abstract
- Moth-eye nanostructures are amongst the most remarkable surfaces in nature because of their multi-functionality including antireflection, self-cleaning and bactericidal ability. Moth-eye surfaces consist of subwavelength arrays of tapered nanostructures, which are challenging to reproduce artificially. Nanoimprint lithography is probably one of the most suited technologies for this purpose. However, the poor mechanical resilience and durability of the polymeric nanocones when exposed to the environment, hinders their use in actual applications. To overcome these limitations, this work demonstrates the use of a thin oxide coating over the polymer moth-eye features imprinted on poly methyl methacrylate (PMMA) films. Particularly TiO2 conformal thin film coatings are deposited by unipolar pulsed dc magnetron sputtering over the antireflective nanopatterns acting as encapsulant. The coating, while preserving the antireflective properties, protects the nanostructures against mechanical scratching and improves substantially their thermal stability to over 250 ?. Furthermore, the TiO2 layer provides additional photoinduced self-cleaning functionality and at the same time it protects the matrix from UV photodegradation. The robust and durable antireflective surfaces developed here may find application on solar cells covers, flat panel displays or on optical components.
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