Search results for "vacuum deposition"

Single-Source Vacuum Deposition of Mechanosynthesized Inorganic Halide Perovskites

2018

Fully inorganic cesium lead halide perovskite thin films were prepared by an easy, fast and dry process based on single-source vacuum deposition. We investigated the structural and optical characteristics of the so-formed films as a function of chemical composition (chloride, bromide and iodide films were formed), post-deposition thermal annealing, as well as previous mechanosynthesis of perovskite powders. We found out that the CsPbX3 perovskite was preferentially formed for the smaller halides and favored by previous ball-milling of CsX and PbX2 precursors. When bigger halides were used and/or CsX and PbX2 precursors were simply mixed without previous mechanosynthesis, PbX2-rich compounds…

Corrosion resistance of the vacuum arc deposited Ti, TiN and TiO2 coatings on large area glass substrates

2000

An industrial installation for vacuum arc deposition is presented. Its potential in the field of decorative coatings for large area glass sheets is demonstrated. In particular it is possible to deposit patterned coatings through a polymeric textile mask. The ability to deposit uniform multilayer coatings having interference colours onto large silicate glass sheets is shown. Titanium, titanium nitride and titanium dioxide coatings on silicate glass have been characterized in terms of composition and corrosion resistance. Depth profiling was achieved with the aid of Auger electron spectroscopy. The corrosion resistance of TiN coatings is higher than that of TiO 2 . The corrosion resistance of…

Molecular Passivation of MoO3: Band Alignment and Protection of Charge Transport Layers in Vacuum-Deposited Perovskite Solar Cells

2019

Vacuum-deposition of perovskite solar cells can achieve efficiencies rivalling solution-based methods and it allows for more complex device stacks. MoO3 has been used to enhance carrier extraction to the transparent bottom electrode in a p-i-n configuration, here we show that by inserting an organic charge transport molecule it can also be used on the top of a perovskite absorber in a n-i-p configuration. This strategy enables the first vacuum-deposited perovskite solar cells with metal oxides as charge transporting layers for both electrons and holes leading to power conversion efficiency > 19 %.

Efficient Photo- and Electroluminescence by Trap States Passivation in Vacuum-Deposited Hybrid Perovskite Thin Films

2018

Methylammonium lead iodide (MAPI) has excellent properties for photovoltaic applications, although it typically shows low photoluminescence quantum yield. Here, we report on vacuum-deposited MAPI perovskites obtained by modifying the methylammonium iodide (MAI) to PbI2 ratio during vacuum deposition. By studying the excitation density dependence of the photoluminescence lifetime, a large concentration of trap states was deduced for the stoichiometric MAPI films. The use of excess MAI during vacuum processing is capable of passivating these traps, resulting in luminescent films which can be used to fabricate planar light-emitting diodes with quantum efficiency approaching 2%.

Vacuum Deposited Triple-Cation Mixed-Halide Perovskite Solar Cells

2018

Hybrid lead halide perovskites are promising materials for future photovoltaics applications. Their spectral response can be readily tuned by controlling the halide composition, while their stability is strongly dependent on the film morphology and on the type of organic cation used. Mixed cation and mixed halide systems have led to the most efficient and stable perovskite solar cells reported, so far they are prepared exclusively by solution-processing. This might be due to the technical difficulties associated with the vacuum deposition from multiple thermal sources, requiring a high level of control over the deposition rate of each precursor during the film formation. In this report, the…

Room temperature vacuum-deposition of CsPbI2Br perovskite films from multiple-sources and mixed halide precursors

2020

Fully inorganic cesium lead halide perovskites, such as CsPbI2Br, show enhanced thermal stability compared to hybrid ones and are being widely investigated as wide bandgap absorbers for tandem applications. Despite their simple stoichiometry, the preparation of highly crystalline and stable cesium lead halide thin films is not trivial. In general, high-efficiency solar cells based on solution-processed CsPbI2Br thin films are prepared by hightemperature annealing or the use of chemical additives. In this work, we use solvent-free synthesis to investigate the formation of CsPbI2Br in bulk or in thin films via mechanochemical synthesis and multiple-source vacuum deposition, respectively. We d…

Thin Film Organic Thermoelectric Generator Based on Tetrathiotetracene

2017

This is the peer reviewed version of the following article: K. Pudzs, A. Vembris, M. Rutkis, S. Woodward, Adv. Electron. Mater. 2017, 1600429, which has been published in final form at http://onlinelibrary.wi...002/aelm.201600429/full This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Vacuum deposition of perovskite films and solar cells

2019

FAPb0.5Sn0.5I3: A Narrow Bandgap Perovskite Synthesized through Evaporation Methods for Solar Cell Applications

2020

The tunability of the optoelectrical properties upon compositional modification is a key characteristic of metal halide perovskites. In particular, bandgaps narrower than those in conventional lead‐based perovskites are essential to achieve the theoretical efficiency limit of single‐absorber solar cells, as well as develop multijunction tandem devices. Herein, the solvent‐free vacuum deposition of a narrow bandgap perovskite based on tin-lead metal and formamidinium cation is reported. Pinhole‐free films with 1.28 eV bandgap are obtained by thermal codeposition of precursors. The optoelectrical quality of these films is demonstrated by their use in solar cells with a power conversion effici…

Perovskite-Perovskite Homojunctions via Compositional Doping.

2018

One of the most important properties of semiconductors is the possibility of controlling their electronic behavior via intentional doping. Despite the unprecedented progress in the understanding of hybrid metal halide perovskites, extrinsic doping of perovskite remains nearly unexplored and perovskite–perovskite homojunctions have not been reported. Here we present a perovskite–perovskite homojunction obtained by vacuum deposition of stoichiometrically tuned methylammonium lead iodide (MAPI) films. Doping is realized by adjusting the relative deposition rates of MAI and PbI2, obtaining p-type (MAI excess) and n-type (MAI defect) MAPI. The successful stoichiometry change in the thin films is…