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In this work we report a simple and cost‐effective CsPbBr3‐based solar cell without ordinary selective contacts. To do so we follow an electrochemical approach consisting of three successive steps: (1) electrodeposition of PbO2 directly on top of FTO substrates, (2) heterogeneous phase reaction with gaseous HBr and (3) spin‐coating of methanolic CsBr solutions followed by annealing. This method is more adequate for large‐scale environmentally friendly production as it reduces chemical waste, particularly toxic lead. The resulting films were structurally and optically characterized showing good coverage of the FTO substrates, absence of defects such as pinholes and orthorhombic structure. Photovoltaic and impedance characterization was carried out by pressing a carbon coated metal spring onto the CsPbBr3 film until obtaining maximized open‐circuit potential (Voc) and short‐circuit photocurrent density (jsc) under simulated sunlight. The stabilized current at fixed voltage (SCFV) technique gave a maximum PCE value of 2.70 % close to devices with similar configuration. Impedance measurements demonstrated analogous behavior to that of state‐of‐art CsPbBr3 based solar cells, comprising a recombination arc at mid‐high frequencies, geometrical capacitance and ideality factors closed to 2, typical of SRH recombination in the perovskite bulk. [ABSTRACT FROM AUTHOR]

This work shows the formation of a heterojunction between tin (II) sulfide (SnS) and electrochemically reduced graphene oxide (ERGO), carried out through two electrochemical steps. In the first step, graphene oxide (GO) was electrochemically reduced on a fluorine‐doped tin oxide (FTO) electrode. In the second step, the ERGO/FTO substrate was used as an electrode for the electrodeposition of SnS. In this study, each electrodeposited material (ERGO, SnS and SnS/ERGO heterojunction) was analyzed and characterized using different techniques, which confirmed the SnS/ERGO heterojunction formation. By employing electrochemical impedance spectroscopy (EIS) and linear sweep photovoltammetry measurements, it was confirmed that SnS deposited in both, bare FTO and ERGO, is a p‐type semiconductor. Furthermore, an improvement of the photocatalytic properties of the SnS/ERGO photocathode in comparison with the SnS film was observed. This effect is related to the ERGO interlayer between the SnS film and the FTO electrode, and the structural and morphology modification of the SnS film onto ERGO. Water splitting: An SnS/ERGO (electrochemically reduced graphene oxide) heterojunction is formed by two electrochemical steps. This heterojunction shows a better photoelectrochemical activity than SnS thin films electrodeposited under the same conditions, which makes it a promising photocathode for water‐splitting applications. [ABSTRACT FROM AUTHOR]

P-type CuSCN nanorods (NRs) grown on CuSCN seed layers were obtained with modulated diameters through an electrochemical procedure. Their morphological, structural, optical, electrochemical and photoelectrochemical features were studied in depth. Morphology of samples can be tuned from a near vertically and dense 1D nanostructure to a quasi 2D film according the value of the SCN – /Cu 2+ molar ratio ( r ) present in the electrochemical bath. Raman studies confirmed the nature of CuSCN in its beta phase. For low r values CuSCN NRs presented high preferential orientation along the c-axis and high optical scattering at low wavelengths which lead to both low haze and high integrated diffuse reflectance. Band gap values were also affected by the r value thus experiencing a redshift, probably related to both quantum confinement and light dispersion. Electrochemical and photoelectrochemical measurements confirmed the p-type behavior of samples together with the enhancement of their surface at low r values. This knowledge opens new and more objective perspectives in the real use of CuSCN nanostructures in photovoltaics. [ABSTRACT FROM AUTHOR]

Electrodeposition of conformal and compact SnO 2 films on transparent conductive oxides (TCOs) has been hardly achieved thus limiting its application in fully solid solar cells such as those based in perovskite absorbers. Here are presented high-quality n-type semiconducting tin (VI) oxide (SnO 2) thin films, successfully grown using a hybrid potentiodynamic/potentiostatic approach on both ITO and FTO coated glass substrates after a detailed optimization that included both annealing steps between eletrodepositions. A solution chemistry study together with a spectrophotometric analysis was useful to determine the one-hour time window of stability for the chosen electrolyte as source of tin. Formation mechanisms based in thermodynamic data and accumulated mass measurements using an electrochemical quartz crystal microbalance (EQCM) are discussed. From the EQCM study the growth rate of films was also estimated in good agreement with high resolution transmission electron microscopy (HR-TEM) analysis. Field emission scanning electron microscopy (FE-SEM) images and X-ray diffraction (XRD) data revealed that substrates are well-covered, crystalline, conformal and free of defects (e.g. without pinholes). The absence of these defects was also well supported by cyclic voltammetry measurements using the ferricyanide/ferrocyanide redox couple. XPS also confirmed the presence of Sn4+ in optimized films. From the optical properties, after carefully eliminating the influence of oscillations due to interference, a direct bandgap energy at 3.60 eV can be deduced. Another indirect bandgap energy at 3.30 eV can also be possible. The hybrid potentiodynamic/potentiostatic protocol to prepare SnO 2 paves a way to prepare compact, transparent and well covering films suitable as electron transporting layer (ETL) for applications in both photoelectrochemical and solid-state solar cells. [ABSTRACT FROM AUTHOR]

In this study, the electrodeposition of a composition-graded stacked CdS x Se (1–x) multilayer film is a matter which is reported for the first time. The electrodeposition was carried out using CdSO 4 , Na 2 S 2 O 3 and SeO 2 as precursors in an acid solution. Previously, an exhaustive electrochemical study was carried out in order to establish the best condition for the electrodeposition of this structure. In order to confirm the feasibility of the method proposed, CdS x Se (1–x) single-layer films of different composition were electrodeposited and characterized. The electrodeposition of the composition-graded stacked layer arrangement was potentiostatically performed through successive electrodeposition steps in a unique electrolytic solution in which its Se content is gradually increases. The characterization of both, single-layer films and multilayer structure was performed using different techniques, confirming the formation of an alloy between CdS and CdSe. Furthermore, the multilayer structure composition gradually changes from pure CdS to a rich selenium CdS x Se (1–x) compound as the electrolytic solution composition increases its SeO 2 , forming a depth bandgap graded material. [ABSTRACT FROM AUTHOR]

Thin films of copper(I) oxide (Cu2O) were electrodeposited on fluorine-doped tin oxide predeposited glass substrates, by reduction of Cu2+ from Cu(II) acetate acid aqueous solutions. The Cu2O was potentiostatically grown at a potential value of −0.450 V (vs. SMSE) at 70 °C. The Cu2O thin films were characterized by means of scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), optical transmission, electrochemical impedance spectroscopy, and photoelectrochemical experiments. Through these techniques, it was possible to establish the cubic Cu2O phase with a high crystallinity and a strong preferential growth along the [200] and [220] directions. Cu2O thin films show oxygen vacancies with formation of a nonstoichiometric compound with the presence of Cu(0) in the crystal lattice as determined by XPS analysis. In addition, Cu2O was used as the photoanode for the I− oxidation reaction when the system was illuminated ( Φ0 = 50.0 mW cm−2). The films exhibited a clear n-type semiconductor behavior, which was in agreement with the Mott-Schottky results. This behavior was explained by considering the nonstoichiometry of the oxide. [ABSTRACT FROM AUTHOR]