Correlation between photoelectrochemical and photoluminescence measurements of Ag-doped ZnO/ITO photoanode

Abstract

Silver-doped zinc oxide (SZO) thin films have been deposited onto indium-doped tin oxide substrates (ITO) using sol–gel spin-coating technique with different Ag doping content (1, 2 and 5% Ag). The effect of silver incorporation on structural, morphological, optical and photoelectrochemical (PEC) properties of the SZO films was investigated. Ag incorporation resulted in an enhanced grain size and thickness of elaborated SZO films. Scanning electron micrographs exhibited a uniform distribution of spherical grains with particle size increment after doping. Band gap energies were found to increase after Ag doping. Photoluminescence (PL) measurements revealed that the energy band gaps of the films were in the UV region. As compared to pure ZnO thin film, the samples are more photoactive, and the film containing 2% Ag yielded the highest photocurrent. A correlation study between PEC and PL measurements of Ag-doped ZnO/ITO photoanode leads to a reverse variation. Charge transfer processes at the ZnO–electrolyte interface were identified by electrochemical impedance spectroscopy.

Enhanced Photocatalytic Activity of Vanadium-Doped SnO2 Nanoparticles in Rhodamine B Degradation

“…is behavior can be explained by the charge transfer process from the valence band (VB) of SnO 2 to the t 2g energy level of vanadium which is located just below the conduction band (CB) [56]. e band-gap energy of undoped and SnO 2 : V NPs was determined using the Tauc-Lorentz expression [65]:…”

Electrodeposition of cadmium selenide based photoanodes from TOMAC/Formamide ionic liquid for photoelectrochemical applications

“…Figure 6a displays the Nyquist plot and the relation between the imaginary (Z") and the real (Z') impedance components of CdSe thin lm. In the studied frequency range, one larger capacitive semicircle was appeared, giving indication to a higher interfacial impedance (electrode/electrolyte) [34,37]. It is also well known that Nyquist plot with larger diameter semicircle usually demonstrates a better corrosion resistance [38].…”

“…The average size of the nanocrystalline compound can be evaluated using the Debye-Scherrer equation: 1 where D presented the regular crystallite size of the studied nanocrystals, λ correspond to the wavelength of the used X-ray radiation, β note the fullwidth of the half-maximum of the oriented peak and, θ B Bragg angle, and k is a constant which having generally a value about 0.94 for cubic phases crystals [34]. Using the preferred (1 1 1) orientation peak, the estimated crystallite size of the nanocrystals CdSe was close to 15.89 nm.…”

“…This means that electrons transition can be possible at lower energy. From this spectra optical band gap energy (E g ) was estimated using Tauc formula [34][35][36][37]:…”

Red luminescence and UV light generation of europium doped zinc oxide thin films for optoelectronic applications

“…These techniques lead to the production of high films quality, however they are expensive (purchase + maintenance). Hence the orientations towards less expensive investment techniques like the sol-gel method [31], electrochemistry [32] or even synthesis by "spray pyrolysis" [33][34][35]. These methods are easier to implement and lead to good quality materials.…”