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Hybrid vapor deposition is one of the most appealing processes for perovskite photovoltaics fabrication, thanks to its versatile nature. By using sequentially different vapor deposition processes tailored to the inorganic and organic perovskite precursors' peculiarities, this type of process gives access to the full potential of vapor deposition. While vapor deposition of metal halides is well understood and mastered, vapor deposition of organohalide species is much more delicate (degradation of vapors, high vapor pressure, setup‐specific constraints). Here, a novel close space sublimation system is reported and in‐depth insights on the conversion into perovskite of a metal halide template are provided. In this evolution of the process, the substrate coated with metal halide template and the organohalide source are loaded together in a dedicated holder, then transferred into a vacuum chamber on a heating element already at temperature setpoint. The system enables a simple, fast, low‐cost, and easy‐to‐reproduce organohalide vapor deposition process. The formation of the perovskite in situ and identification different conversion regimes are studied. Furthermore, the influence of the chemical environment and chamber design on the process are discussed. Compositional tuning and additive engineering in the process are processed and fabricate proof of concept photovoltaic devices reaching high fill factors of 80% and 17% power conversion efficiency for a bandgap of 1.63 eV. [ABSTRACT FROM AUTHOR]

The incorporation of large organic ammonium ions renders the crystallization dynamics and layer formation process of halide perovskites complex, difficult to control, and leads to problems of suppressed charge transport with the formation of tiny‐sized grains. In this paper, the use of methylammonium chloride (MACl) and an excess of PbI2 is introduced as a co‐additives in the precursor solution for the control of phenylmethylammonium or benzylammonium (PMA+ spacer) and formamidinium (FA+)‐based quasi‐2D PMA2FAn−1PbnI3n+1 (n = 5) perovskite layers formation. By this method, the morphology of the layer, the inner phase distribution, and the charge transport properties are improved. By employing glow discharge‐optical emission spectroscopy (GD‐OES) and other techniques, it is revealed that the quasi‐2D perovskites prepared in the presence of co‐additives exhibit uniform removal dynamics of the solvent across the film. Furthermore, the grain growth mode, upon thermal annealing, is lateral. It results in large, monolithic grains with low‐trap state density and excellent substrate coverage. Particularly, co‐additives improve the cations dispersion upon the crystallization process, thus suppressing the low‐n phase formed through the aggregation of spacer cations and accelerating the formation of the high‐n phase. [ABSTRACT FROM AUTHOR]

The transition metal dichalcogenides have been studied for various applications in electronics, sensing, or spintronics. Molybdenum ditelluride, MoTe2, occurs in 3 crystal systems: hexagonal (2H), monoclinic (1T′), and orthorhombic (Td). Here we report on tellurisation of Mo and MoO3 thin films to 2H-MoTe2 and 1T′-MoTe2 thin layers on sapphire substrates, respectively. To study the phases, we employed diffraction patterns using grazing-incidence wide-angle X-ray scattering, conventional X-ray diffraction and transmission electron microscopy (TEM). Measurements of pole figures confirmed the presence of a biaxial texture of both 1T′ and 2H phases. In the hexagonal phase, we found two ensembles of biaxially oriented crystallites offset by 30 degrees between the two groups. On the other hand, in the monoclinic layer, the crystallites follow the six-fold symmetry of the (0001) sapphire surface. [ABSTRACT FROM AUTHOR]

The development of an efficient fabrication route to achieve high‐resolution perovskite pixel array is key for large‐scale flexible image sensor devices. Herein, a high‐resolution and stable 10 × 10 flexible PDs array based on formamidinium(FA+) and phenylmethylammonium (PMA+) quasi‐2D (PMA)2FAPb2I7 (n = 2) perovskite is demonstrated by developing SiO2‐assisted hydrophobic and hydrophilic treatment process on polyethylene terephthalate substrate. By introducing Au nanoparticles (Au NPs), the perovskite film quality is improved and grain boundaries are reduced. The mechanism by which Au NPs upgrade the photoelectric quality of perovskite is mainly revealed by glow discharge‐optical emission spectroscopy (GD‐OES) and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). To further improve the photoelectric performance of the devices, a post‐treatment strategy with formamidinium chloride (FACl) is used. The optimized flexible PDs arrays show excellent optoelectronic properties with a high responsivity of 4.7 A W−1, a detectivity of 6.3 × 1012 Jones, and a broad spectral sensitivity. The device also exhibits excellent electrical stability even under severe bending and excellent flexural strength, as well as excellent environmental stability. Finally, the integrated flexible PDs arrays are used as sensor pixels in an imaging system to obtain high‐resolution imaging patterns, demonstrating the imaging capability of the PDs arrays. [ABSTRACT FROM AUTHOR]

Textured silicon wafers used in silicon solar cell manufacturing offer superior light trapping, which is a critical enabler for high‐performance photovoltaics. A similar optical benefit can be obtained in monolithic perovskite/silicon tandem solar cells, enhancing the current output of the silicon bottom cell. Yet, such complex silicon surfaces may affect the structural and optoelectronic properties of the overlying perovskite films. Here, through extensive characterization based on optical and microstructural spectroscopy, it is found that the main effect of such substrate morphology lies in an altering of the photoluminescence response of the perovskite, which is associated with thickness variations of the perovskite, rather than lattice strain or compositional changes. With this understanding, the design of high‐performance perovskite/silicon tandems is rationalized, yielding certified power conversion efficiencies of >28%. [ABSTRACT FROM AUTHOR]

A perovskite solar cell (PSC) featuring a mesoporous architecture can facilitate perovskite layer formation over a large area via increasing the number of heterogeneous nucleation sites. The morphology of the electron transport layer (ETL) and its interface with the perovskite layer is one of the key factors to boost the performance of a PSC. Tin dioxide (SnO2) is considered as a promising ETL in PSCs owing to its high carrier mobility, good transmittance, deep conduction band level, and efficient photoelectron extraction. Generally, the mesoporous SnO2 (m-SnO2) ETL has a higher surface-to-volume ratio compared to a compact SnO2 layer. Herein, we report on an m-SnO2 ETL prepared by anodizing a metallic tin film on a fluorine-doped tin oxide (FTO) substrate in NaOH solution under an ambient atmosphere. In particular, we developed a bilayer architecture of the m-SnO2 ETL based on the fabrication of two consecutive m-SnO2 layers. The morphology of each layer was controlled by varying the anodization voltage and time at a constant solution concentration during the growth process. This unique approach enabled the deposition of an m-SnO2 ETL with sufficient coverage of the FTO substrate, which is difficult to achieve with a single layer of m-SnO2. In particular, the scanning electron and atomic force microscopy analyses confirmed that the m-SnO2 layer covers completely the FTO substrate. The device fabricated with this bilayer m-SnO2 ETL achieved a 27% improvement in power conversion efficiency compared to that with a single layer of m-SnO2. [ABSTRACT FROM AUTHOR]

At present, the power conversion efficiency of single-junction perovskite-based solar cells reaches over 26%. The further efficiency increase of perovskite-based optoelectronic devices is limited mainly by defects, causing the nonradiative recombination of charge carriers. To improve efficiency and ensure reproducible fabrication of high-quality layers, it is crucial to understand the perovskite nucleation and growth mechanism along with associated process control to reduce the defect density. In this study, we investigate the growth kinetics of a promising narrow bandgap perovskite, formamidinium methylammonium lead iodide (FAMAPbI 3 ), for high-performance single-junction solar cells. The temporal evolution of structural and optoelectronic properties during FAMAPbI 3 vacuum codeposition was inspected in real time by grazing-incidence wide-angle X-ray scattering and photoluminescence. Such a combination of analytical techniques unravels the evolution of intrinsic defect density and layer morphology correlated with lattice strain from the early stages of the perovskite deposition.

Molybdenum disulfide (MoS 2 ) few-layer films have gained considerable attention for their possible applications in electronics and optics and also as a promising material for energy conversion and storage. Intercalating alkali metals, such as lithium, offers the opportunity to engineer the electronic properties of MoS 2 . However, the influence of lithium on the growth of MoS 2 layers has not been fully explored. Here, we have studied how lithium affects the structural and optical properties of the MoS 2 few-layer films prepared using a new method based on one-zone sulfurization with Li 2 S as a source of lithium. This method enables incorporation of Li into octahedral and tetrahedral sites of the already prepared MoS 2 films or during MoS 2 formation. Our results discover an important effect of lithium promoting the epitaxial growth and horizontal alignment of the films. Moreover, we have observed a vertical-to-horizontal reorientation in vertically aligned MoS 2 films upon lithiation. The measurements show long-term stability and preserved chemical composition of the horizontally aligned Li-doped MoS 2 ., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)