Effects of Iodine Doping on Electrical Characteristics of Solution-Processed Copper Oxide Thin-Film Transistors

Beyond the ordinary: exploring the synergistic effect of iodine and nickel doping in cobalt hydroxide for superior energy storage applications

This study explores the iodine and nickel-doped cobalt hydroxide (I & Ni-co-doped-Co(OH)2) as a potential material for energy storage and conversion applications owing to its excellent electrochemical characteristics. According to our analysis, it was revealed that this material exhibits pseudocapacitive-like behavior, as evident from distinct redox peaks observed in cyclic voltammetry, which confirms its ability to store charges. The diffusion coefficient analysis reveals that this material possesses conductivity and rapid diffusion kinetics, making it particularly advantageous compared to materials synthesized in previous studies. Charge-discharge measurements were performed to analyze the charge storage capacity and stability of this material after 3000 consecutive cycles, showing its excellent stability with minimum loss of capacitance. Furthermore, its anodic and cathodic linear sweep voltammetry curves were measured to evaluate its oxygen evolution and hydrogen evolution reaction performance. The results showed that the material exhibited an excellent water splitting performance, which suggests its potential practical application for hydrogen production. This increased activity was attributed to the doping of α-Co(OH)2, which improved its structural stability, electrical conductivity, and charge transfer efficiency. Thus, I & Ni-co-doped-Co(OH)2 possesses enhanced properties that make it an excellent material for both energy storage and hydrogen generation applications.

Ca-Doped Copper (I) Oxide Deposited via the Spray Coating Technique for Heterojunction Solar Cell Application

In this report, the morphological, optical, electrical, and photovoltaic properties of copper oxide and calcium-doped copper oxide thin films produced via the spray coating method were studied. The thermal post treatment at 300 °C in an inert atmosphere allowed us to obtain a single phase of Cu2O with 21 Ωcm of resistivity (ρ). In this study, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and 10 wt% Ca admixtures with copper oxide were investigated. The determined optimal calcium dopant concentration was 4 wt%. XRD analysis was used to reveal the chemical composition of the produced layers. It was found that a calcium dopant does not change the layer composition but improves its electrical parameters. Based on UV-Vis spectra, the band gap energy and Urbach energy were calculated. The morphology of produced thin films was described as smooth and nanocrystalline, corresponding to a grain size calculated based on the Scherrer equation. Finally, it was shown that the developed protocol of low-resistivity copper oxide deposition via the spray coating technique can be successfully implemented in heterojunction solar cell production. The I-V parameters of Ag/n-type CzSi/REF:CuOx and 4Ca:CuOx/Carbon were collected, and the achieved efficiency was 2.38%.

MnO2-Induced Oxidation of Iodide in Frozen Solution

Metal oxides play a critical role in the abiotic transformation of iodine species in natural environments. In this study, we investigated iodide oxidation by manganese dioxides (β-MnO₂, γ-MnO₂, and δ-MnO₂) in frozen and aqueous solutions. The heterogeneous reaction produced reactive iodine (RI) in the frozen phase, and the subsequent thawing of the frozen sample induced the gradual transformation of in situ-formed RI to iodate or iodide, depending on the types of manganese dioxides. The freezing-enhanced production of RI was observed over the pH range of 5.0-9.0, but it decreased with increasing pH. Fulvic acid (FA) can be iodinated by I^-/MnO₂ in aqueous and frozen solutions. About 0.8-8.4% of iodide was transformed to organoiodine compounds (OICs) at pH 6.0-7.8 in aqueous solution, while higher yields (10.4-17.8%) of OICs were obtained in frozen solution. Most OICs generated in the frozen phase contained one iodine atom and were lignin-like compounds according to Fourier transform ion cyclotron resonance/mass spectrometry analysis. This study uncovers a previously unrecognized production pathway of OICs under neutral conditions in frozen environments.

An efficient and stable iodine-doped nickel hydroxide electrocatalyst for water oxidation: synthesis, electrochemical performance, and stability

The design of oxygen evolution reaction (OER) catalysts with higher stability and activity by economical and convenient methods is considered particularly important for the energy conversion technology. Herein, a simple hydrothermal method was adopted for the synthesis of iodine-doped nickel hydroxide nanoparticles and their OER performance was explored. The electrocatalysts were structurally characterized by powder X-ray diffraction analysis (P-XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and BET analysis. The electrochemical performance of the electrocatalysts was assessed by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. The abundant catalytic active sites, oxygen vacancies, low charge-transfer resistance, and a high pore diameter to pore size ratio of iodine-doped Ni(OH)₂ were responsible for its excellent catalytic activity, whereby OER was initiated even at 1.52 V (vs. RHE) and a 330 mV overpotential was needed to reach a 40 mV cm⁻² current density in 1 M KOH solution. The material also exhibited a low Tafel slope (46 mV dec⁻¹), which suggests faster charge-transfer kinetics as compared to its counterparts tested under the same electrochemical environment. It is worth noting that this facile and effective approach suggests a new way for the fabrication of metal hydroxides rich in oxygen vacancies, thus with the potential to boost the electrochemical performance of energy-related systems.

Oxygen evolution reaction mechanism under alkaline conditions over the iodine-doped Ni(OH)₂ surface.