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Metal halide perovskite solar cells (MHPSCs) hold great promise related to their high efficiency and low fabrication costs, but their long-term stability under environmental conditions remains a major challenge. In this study, we demonstrate an effective protection strategy to enhance the stability of MHPSCs through the incorporation of a double passivation layer based on an adamantane-based plasma polymer (ADA) at both the electron transport layer (ETL)/perovskite and perovskite/hole transport layer (HTL) interfaces. Our results show that the implemented ADA deposition technique is compatible with delicate substrates such as perovskites thin films, as their optical, morphological and optoelectronic properties are unaltered upon ADA deposition. At the same time, it provides effective protection to the perovskite material in high humidity environments. The ADA-double passivation not only reduces the formation of mobile ionic defects that cause additional recombination, but also significantly reduces humidity-induced degradation and mitigates the photocatalytic degradation caused by TiO2 under UV exposure. Stability tests performed under 100% relative humidity and continuous AM 1.5G illumination (ISOS-L-1) show that ADA dual passivated devices retained 80% of their initial efficiency after 4000 minutes, while reference samples dropped to 30%. The enhanced performance of ADA-passivated cells is attributed to protective nature of the plasma polymer layer resulting in a preservation of photocurrent and the prevention of new recombination routes. This dual passivation strategy offers a promising route to improve the environmental stability of PSCs and extend their operational lifetime.

Hybrid organometal halide perovskites (HP) present exceptional optoelectronic properties, but their poor long-term stability is a major bottleneck for their commercialization. Herein, we present a solvent-free approach to growing single-crystal organic nanowires (ONW), nanoporous metal oxide scaffolds, and HP to form a core@multishell architecture. The synthetic procedure is carried out under mild vacuum conditions employing thermal evaporation for the metal-free phthalocyanine (H2Pc) nanowires, which will be the core, plasma-enhanced chemical vapor deposition (PECVD) for the TiO2 shell, and co-evaporation of lead iodide (PbI2) and methylammonium iodide (CH3NH3I / MAI) for the CH3NH3PbI3 (MAPbI3 / MAPI) perovskite shell. We present a detailed characterization of the nanostructures by (S)-TEM and XRD, revealing a different crystallization of the hybrid perovskite depending on the template: while the growth on H2Pc nanowires induces the typical tetragonal structure of the MAPI perovskite, a low-dimensional phase (LDP) was observed on the one-dimensional TiO2 nanotubes. Such a combination yields an unprecedentedly stable photoluminescence emission over 20 hours and over 300 hours after encapsulation in polymethyl methacrylate (PMMA) under different atmospheres including N2, air, and high moisture levels. In addition, the unique one-dimensional morphology of the system, together with the high refractive index HP, allows for a strong waveguiding effect along the nanowire length.

Despite the youthfulness of hybrid halide perovskite solar cells, their efficiencies are currently comparable to commercial silicon and have surpassed quantum-dots solar cells. Yet, the scalability of these devices is a challenge due to their low reproducibility and stability under environmental conditions. However, the methods reported to date to tackle such issues recurrently involve the use of solvent methods that would further complicate their transfer to industry. Herein we present a reliable alternative relaying in the implementation of an ultrathin plasma polymer as passivation interface between the electron transport material and the hybrid perovskite layer. Such nanoengineering interface provides solar devices with increased long-term stability under ambient conditions. Thus, without consideringr any additional encapsulation step, the cells retain more than 80 % of their efficiency after being exposed to the ambient atmosphere for more than 1000 h. Moreover, this plasma polymer passivation strategy significantly improves the coverage of the mesoporous scaffold by the perovskite layer, providing the solar cells with enhanced performance as well as improved reproducibility.

Polarizers are ubiquitous components in optoelectronic devices of daily use as displays, optical sensors or photographic cameras, among others. Yet the control over light polarization is an unresolved challenge as the main drawback of the current display technologies relays in significant optical losses. In such a context, organometal halide perovskites can play a decisive role given their flexible synthesis with under design optical properties . Therefore, along with their outstanding electrical properties have elevated hybrid perovskites as the material of choice in photovoltaics and optoelectronics. Among the different organometal halide perovskite nanostructures, nanowires and nanorods have lately arise as key players for the control of light polarization for lighting or detector applications. Herein, we will present the unprecedented fabrication of highly aligned and anisotropic methylammonium lead iodide (MAPI) perovskite nanowalls by Glancing Angle Deposition of PbI2 under high vacuum followed by CH3NH3I deposition at normal angle. Our approach offers a direct route for the fabrication of perovskite nanostructures virtually on any substrate, including on photovoltaic devices. The unparalleled alignment degree of the perovskite nanowalls provides the samples with strong anisotropic optical properties such as light absorption and photoluminescence, the latter with a maximum polarization ratio of P=0.43. Furthermore, the implementation of the MAPI nanowalls in photovoltaic devices provides them with a polarization-sensitive response, with a maximum photocurrent difference of 2.1 % when illuminating with the near-infrared range of the solar spectrum (>700 nm). Our facile vacuum-based approach embodies a milestone in the development of last generation polarization-sensitive perovskite-based optoelectronic devices such as lighting appliances or self-powered photodetectors., Comment: 29 Pages, 6 Figures, Supplementary Information with 4 Figures and 1 Note

The growth of amorphous TiO2 and anisotropic-polycrystalline ZnO thin-films is studied by means of coarse-grained three-dimensional kinetic Montecarlo simulations under conditions typically encountered in Plasma Enhanced Chemical Vapor Deposition experiments. The approach developed considers fluctuations in the activation energy for surface diffusion of the coarse particles that are calculated on-the-fly and depends on the mesoscale local morphological/structural landscape. The basis of this approach --which is known to work well to simulate the growth of amorphous materials using a much simpler cubic grid-- has been extended in this work to reproduce not only the morphological characteristics and scaling properties of amorphous TiO2 but also the growth of polycrystalline ZnO with a good approximation, including the evolution of the film texture and textured-grain competition during growth and its dependence on experimental conditions. The results of the simulations have been compared with available experimental data obtained by X-Ray Diffraction, analysis of the texture coefficients, Atomic Force Microscopy and Scanning Electron Microscopy, Comment: 21 first pages, including Supporting Information, 9 figures in the main text

The eventual exploitation of one-dimensional nanomaterials yet needs the development of scalable, high yield, homogeneous, and environmentally friendly methods able to meet the requirements for the fabrication of under design functional nanomaterials. In this article, we demonstrate a vacuum and plasma one-reactor approach for the synthesis of the fundamental common element in solar energy and optoelectronics, i.e. the transparent conducting electrode but in the form of nanotubes and nanotrees architectures. Although the process is generic and can be used for a variety of TCOs and wide-bandgap semiconductors, we focus herein on Indium Doped Tin Oxide (ITO) as the most extended in the previous applications. This protocol combines widely applied deposition techniques such as thermal evaporation for the formation of organic nanowires serving as 1D and 3D soft templates, deposition of polycrystalline layers by magnetron sputtering, and removal of the template by simply annealing under mild vacuum conditions. The process variables are tuned to control the stoichiometry, morphology, and alignment of the ITO nanotubes and nanotrees. Four-probe characterization reveals the improved lateral connectivity of the ITO nanotrees and applied on individual nanotubes shows resistivities as low as 3.5 +/- 0.9 x 10-4 {\Omega}.cm, a value comparable to single-crystalline counterparts. The assessment of diffuse reflectance and transmittance in the UV-VIS range confirms the viability of the supported ITO nanotubes as a random optical media working as strong scattering layers. Further ability to form ITO nanotrees opens the path for practical applications as ultra-broadband absorbers in the NIR. The demonstrated low resistivity and optical properties of these ITO nanostructures open the way for their use in LEDs, IR shield, energy harvesting, nanosensors, and photoelectrochemical applications, Comment: 21 pages, 1 schematic, 6 figures, supporting information