Optoelectronics applications of electrodeposited p- and n-type Al2Se3 thin films

In this paper, energy band gaps and electrical conductivity based on aluminum selenide (Al2Se3) thin films are synthesized electrochemically using cathodic deposition technique, with graphite and carbon as cathode and anode, respectively. Synthesis is done at 353 K from an aqueous solution of analytical grade selenium dioxide (SeO2), and aluminum chloride (AlCl2·7H2O). Junctions-based Al2Se3 thin films from a controlled medium of pH 2.0 are deposited on fluorine-doped tin oxide (FTO) substrate using potential voltages varying from 1,000 mV to 1,400 mV and 3 minutes −15 minutes respectively. The films were characterized for optical properties and electrical conductivity using UV-vis and photoelectrochemical cells (PEC) spectroscopy. The PEC reveals a transition in the conduction of the films from p-type to n-type as the potential voltage varies. The energy band gap reduces from 3.2 eV to 2.9 eV with an increase in voltage and 3.3 eV to 2.7 eV with increase in time. These variations indicate successful fabrication of junction-based Al2Se3 thin films with noticeable transition in the conductivity type and energy band gap of the materials. Consequently, the fabricated Al2Se3 can find useful applications in optoelectronic devices.

Protective properties of superhydrophobic coatings on copper and steel obtained by electrochemical method

Superhydrophobic coatings are obtained by cathodic deposition of copper or nickel on a copper plate with treatment with an ethanol solution of highest carboxylic acids with a long hydrocarbon radical simultaneously or sequentially. They are characterized by a contact angle of water wetting of the order of 155...160°.These coatings protect the copper substrate from corrosion in conditions of 100% humidity for 100...180 days, while maintaining the contact angle within 152…154°. There is no mass loss. The influence of the reversal of the current during electrolysis on the value of the contact angle of wetting is investigated. SEM images of superhydrophobic coatings are presented, indicating multilevel roughness. Superhydrophobic coating on carbon steel is obtained by cathodic deposition of nickel and subsequent surface treatment in an ethanol solution of myristic acid and annealing at 60° for two hours. The influence of the duration of electrolysis on the value of the contact angle of wetting is estimated. Its value is in the range of 151…154°. Exposure of a coated steel plate for 50 days in conditions of 100% humidity is characterized by the absence of weight loss and maintaining the contact angle up to 154°.

In situ anodic dissolution–cathodic deposition route for preparation of the Pt–SiW11Co/SiW11Co–CNP/GC electrode: application as an efficient electrode for the hydrogen evolution reaction

A novel nanohybrid based on carbon nanoparticles, platinum nanoparticles, and SiW11Co polyoxometalate is introduced as an efficient electrocatalyst for the hydrogen evolution reaction (HER).

Variation of Cathodic voltages and their effect on Optical Properties and Conductivity Type of Electrodeposited Aluminium Selenide Thin Films for Optoelectronic Applications

In this paper, Aluminum selenide (Al2Se3) thin films are synthesized electrochemically using cathodic deposition technique in which graphite was used as a cathode while carbon as an anode. Synthesis is done at 353 K temperature from an aqueous solution of analytical grade selenium dioxide (SeO2), and Aluminum chloride (AlCl2.7H2O). Aluminum selenide thin films from a controlled medium (pH =2.0) are synthesized on fluorine doped tin oxide (FTO) substrate using varied potential voltages 1000 mV, 1100 mV, 1200 mV, 1300 mV and 1400 mV. The films are characterized for their optical properties and electrical conductivity. These various characterization reveals the successful fabrication of Al2Se3 thin films. Further investigation was done to study the effect of variation in the potential voltages.Keywords- Electrodeposition; Thin Films; Cathodic graphite; Characterization; Varied potential voltages.