Underpotential deposition of cobalt onto polycrystalline platinum

An electrochemical study of cobalt electrodeposition onto a polycrystalline platinum electrode from an aqueous solution (10⁻² M CoCl₂ + 1 M NH₄Cl (pH 9.5)) was carried out through cyclic voltammetry and potential step techniques. Analysis of the voltammetric data clearly showed that a cobalt adlayer is formed during the application of potential in the underpotential deposition (upd) region. Formation of this cobalt adlayer involved the simultaneous presence of both adsorption and 2D nucleation processes. Cobalt adlayers obtained by linear voltammetry in upd region were analyzed employing diffuse reflectance spectroscopy (DRS). By using theoretical quantum studies at PM6//HF/LANL1MB level, it was possible to assign the peaks obtained by DRS at 328 and 337 nm to the cobalt adsorption on Pt(111) and Pt(100), respectively, while the signals recorded at 355 and 362 nm were related with the clean platinum surfaces Pt(100) and Pt(111). Also, quantum calculations at the PM6 level indicated that the energy formation order is Co-Pt(100) > Co-Pt(111) > Co-Pt(110) > Co-Co(surface).     

On the pseudocapacitive behavior of nanostructured molybdenum oxide

Nanostructured molybdenum oxide having a particle size in the range of 30–80 nm was prepared by potentiodynamic electrodeposition method, and the effects of H₂SO₄ concentration on its capacitive behavior were studied by cyclic voltammetry, galvanostatic discharge, and electrochemical impedance spectroscopy. Poor to fair capacitive behaviors were witnessed depending on the electrolyte concentration and conditions of charge/discharge. Increasing acid concentration to 0.02 M had favorable effect, while beyond that, the effect was detrimental. Capacitance around 600 F g⁻¹ was recorded in the potential range of 0 to −0.55 V vs. Ag/AgCl.     

Development of a sequential injection–square wave voltammetry method for determination of paraquat in water samples employing the hanging mercury drop electrode

This work describes the development and optimization of a sequential injection method to automate the determination of paraquat by square-wave voltammetry employing a hanging mercury drop electrode. Automation by sequential injection enhanced the sampling throughput, improving the sensitivity and precision of the measurements as a consequence of the highly reproducible and efficient conditions of mass transport of the analyte toward the electrode surface. For instance, 212 analyses can be made per hour if the sample/standard solution is prepared off-line and the sequential injection system is used just to inject the solution towards the flow cell. In-line sample conditioning reduces the sampling frequency to 44 h⁻¹. Experiments were performed in 0.10 M NaCl, which was the carrier solution, using a frequency of 200 Hz, a pulse height of 25 mV, a potential step of 2 mV, and a flow rate of 100 μL s⁻¹. For a concentration range between 0.010 and 0.25 mg L⁻¹, the current (i _p, μA) read at the potential corresponding to the peak maximum fitted the following linear equation with the paraquat concentration (mg L⁻¹): i _p = (−20.5 ± 0.3)C _paraquat − (0.02 ± 0.03). The limits of detection and quantification were 2.0 and 7.0 μg L⁻¹, respectively. The accuracy of the method was evaluated by recovery studies using spiked water samples that were also analyzed by molecular absorption spectrophotometry after reduction of paraquat with sodium dithionite in an alkaline medium. No evidence of statistically significant differences between the two methods was observed at the 95% confidence level.     

A new amperometric H<Subscript>2</Subscript>O<Subscript>2</Subscript> biosensor based on nanocomposite films of chitosan–MWNTs,hemoglobin, and silver nanoparticles

A new H₂O₂ biosensor was fabricated on the basis of nanocomposite films of hemoglobin (Hb), silver nanoparticles (AgNPs), and multiwalled carbon nanotubes (MWNTs)–chitosan (Chit) dispersed solution immobilized on glassy carbon electrode (GCE). The immobilized Hb displayed a pair of well-defined and reversible redox peaks with a formal potential (E ^θ′) of −22.5 mV in 0.1 M pH 7.0 phosphate buffer solution. The apparent heterogeneous electron transfer rate constants (k _s) in the Chit–MWNTs film was evaluated as 2.58 s⁻¹ according to Laviron’s equation. The surface concentration (Γ*) of the electroactive Hb in the Chit–MWNTs film was estimated to be (2.48 ± 0.25) × 10⁻⁹ mol cm⁻². Meanwhile, the Chit–MWNTs/Hb/AgNPs/GCE demonstrated excellently electrocatalytical ability to H₂O₂. Its apparent Michaelis–Menten constant (K _M^app) for H₂O₂ was 0.0032 mM, showing a good affinity. Under optimal conditions, the biosensors could be used for the determination of H₂O₂ ranging from 6.25 × 10⁻⁶ to 9.30 × 10⁻⁵ mol L⁻¹ with a detection limit of 3.47 × 10⁻⁷ mol L⁻¹ (S/N = 3). Furthermore, the biosensor possessed rapid response to H₂O₂ and good stability, selectivity, and reproducibility.     

Indirect cathodic reduction of dispersed indigo by 1,2-dihydroxy-9,10-anthraquinone-3-sulphonate (Alizarin Red S)

The indirect cathodic reduction of dispersed indigo (Vat Blue 1) with 1,2-dihydroxy-9,10-anthraquinone-3-sulphonate (Alizarin Red S) as soluble mediator system was studied in 0.1 M NaOH by cyclic voltammetry, voltammetry in a flow cell and in galvanostatic reduction experiments. In cyclic voltammetry, the presence of 17.1 mM indigo led to an increase in the diffusion-controlled cathodic peak current (I _p)_d by a factor of 2. During the reverse scan of the voltammograms the oxidation of reduced indigo could be observed at −650 mV (vs. Ag/AgCl, 3 M KCl). In voltrammograms of 4.0 mM ALS in 0.1 M NaOH, recorded in a flow cell, a current density of 0.40–0.46 mA cm⁻² was determined for the diffusion-controlled cathodic current plateau, which appeared in the potential range of −850 to −1,050 mV. In galvanostatic batch electrolysis, solutions containing 2.5–3.8 mM reduced indigo were prepared and analysed by spectrophotometry and tested in dyeing experiments. The dyeing behaviour of the reduced indigo was independent of the reduction technique used. Energy consumption for electrochemical reduction of 1 kg of indigo could be estimated to 6.5 kWh kg⁻¹.     

Coated wire thorium ion selective electrode: Part I

Coated wire ion selective electrode for thorium ion selective potentiometry was developed. Thorium ion selective coated wire electrodes were prepared by depositing a membrane comprising of Aliquat-336 loaded with Th(NO₃)₆²⁻ ions and poly vinyl chloride in varying proportion. A linear near-Nernstian response with a slope of −29.5 ± 0.3 mV over thorium concentration range of 1 × 10⁻¹–3 × 10⁻⁵ M in constant total nitrate concentration of 6 M was obtained for the electrodes of almost all the composition studied. In spite of small drift in response potential from composition to composition, day to day as well as from electrode to electrode, the slope of potential response line was constant within experimental error. Moreover, the electrode once prepared could be conveniently used over a period of one and half month.     

AC impedance investigation of plating potentials on the catalytic activities of Pt nanocatalysts for methanol electrooxidation

Pt nanocatalysts supported on glassy carbon (GC) were electrochemically deposited by cyclic voltammetry (CV) with different scanning potential ranges. The lower limit of potential was fixed at −0.25 V vs. saturated calomel electrode, whereas the upper limit of potential was adjusted to be 0.0, 0.20, 0.60, and 1.0 V. Scanning electron microscopy images showed that Pt microparticles are uniformly dispersed on the GC substrate and the agglomerated microparticles are composed of numerous nanoparticles. In addition, the catalytic capabilities of Pt/GCs for methanol electrooxidation were examined by CV, chronoamperometry, and electrochemical impedance spectroscopy in a solution of 0.5 M CH₃OH and 0.5 M H₂SO₄. The results demonstrate that the catalytic activities and stabilities of Pt catalysts prepared by the potential ranges from −0.25 to both 0.60 and 1.0 V for methanol electrooxidation were higher than the others, which may be due to their higher electrochemical active surface area, lower charge transfer resistance, and more preferred Pt crystallographic orientation.     

Light sensitivity and potential stability of electrically conducting polymers commonly used in solid contact ion-selective electrodes

The results of a systematic study of the light sensitivity and long-term potential stability (30 days) of poly(pyrrole) (PPy), poly(3-octylthiophene) (POT), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(aniline) (PANI) and plasticised poly(vinyl chloride) (PVC) containing 20% (m/m) PANI are reported. Thin films were prepared either electrochemically or by the solution casting technique. This fundamental study is of importance because conducting polymers (CP) are commonly used as ion-to-electron transduction materials in all-solid-state solid contact ion-selective electrodes. The potential stability test done in 0.1 M KCl (pH 7.5) simulates the extreme situation when the CP-based SC becomes in direct contact with water. Films prepared of a nanodispersion of PANI showed both good potential stability and insensitivity to light even under illumination with very intensive light (>10⁵ lx). In contrary, it was observed that POT is very light-sensitive. Upon illumination with intensive light, the potential responses of POT films prepared by solution casting and electropolymerisation were 315 and 590 mV, respectively. A room light sensitivity of approximately −10 to −15 mV was observed for these films. The other CPs in this study were insensitive to room light (∼150 lx), but were light-sensitive under illumination with intensive light. The potential drift of PPy(Cl) is below −10 μV/h (3–30 days), whereas the other most stable CPs in this study had a slightly higher potential drift.     

Structural and optical properties of ZnO thin films by the spin coating Sol-Gel method

ZnO thin films were deposited onto glass subsrates by a Sol-gel spin coating method. The structural and optical properties of ZnO thin films were investigated. The molar ratios of the zinc acetate dihydrate to Monoethanolamine were maintained 1:1. The as-grown film was sintered 250 °C for 10 min, then annealed in air at 500 °C for 30 min. The XRD results indicate that ZnO films were strongly oriented to the c-axis of the hexagonal nature. Absorption measurements were carried out as a function of temperature with 10 K steps in the range 10–320 K. The band gap energy was measured 3.275 and 3.267 eV for 0.5 and 1.0 molarity (M) ZnO thin films at 300 K. The steepness parameters were observed between 10 and 320 K and their extrapolations converged at (E₀, α₀) = 3.65 eV, 172,819 cm⁻¹ and 3.70 eV, 653,436 cm⁻¹ for 0.5 and 1.0 M ZnO thin films, respectively.     

Immobilization of flavine adenine dinucleotide onto nickel oxide nanostructures modified glassy carbon electrode: fabrication of highly sensitive persulfate sensor

A simple method was used to fabricate flavin adenine dinucleotide (FAD)/NiOx nanocomposite on the surface of glassy carbon (GC) electrode. Cyclic voltammetry technique was applied for deposition nickel oxide nanostructures onto GC surface. Owing to its high biocompatibility and large surface area of nickel oxide nanomaterials with immersing the GC/NiOx-modified electrode into FAD solution for a short period of time, 10–140 s, a stable thin layer of the FAD molecules immobilized onto electrode surface. The FAD/NiOx films exhibited a pair of well-defined, stable, and nearly reversible CV peaks at wide pH range (2–10). The formal potential of adsorbed FAD onto nickel oxide nanoparticles film, E ^o′ vs. Ag/AgCl reference electrode is −0.44 V in pH 7 buffer solutions was similar to dissolved FAD and changed linearly with a slope of 58.6 mV/pH in the pH range 2–10. The surface coverage and heterogeneous electron transfer rate constant (k _s ) of FAD immobilized on NiOx film glassy carbon electrode are 4.66 × 10⁻¹¹ mol cm⁻² and 63 ± 0.1 s⁻¹, indicating the high loading ability of the nickel oxide nanoparticles and great facilitation of the electron transfer between FAD and nickel oxide nanoparticles. FAD/NiOx nanocomposite-modified GC electrode shows excellent electrocatalytic activity toward S₂O₈²⁻ reduction at reduced overpotential. Furthermore, rotated modified electrode illustrates good analytical performance for amperometric detection of S₂O₈²⁻. Under optimized condition, the concentration calibration range, detection limit, and sensitivity were 3 μM–1.5 mM, 0.38 μM and 16.6 nA/μM, respectively.     

Simultaneous determination of uric acid and ascorbic acid at the film of chitosan incorporating cetylpyridine bromide modified glassy carbon electrode

A glassy carbon electrode (GCE) modified with the film composed of chitosan incorporating cetylpyridine bromide is constructed and used to determine uric acid (UA) and ascorbic acid (AA) by differential pulse voltammetry (DPV). This modified electrode shows efficient electrocatalytic activity and fairly selective separation for oxidation of AA and UA in mixture solution. UA is catalyzed by this modified electrode in phosphate buffer solution (pH 4.0) with a decrease of 80 mV, while AA is catalyzed with a decrease of 200 mV in overpotential compared to GCE, and the peak separation of oxidation between AA and UA is 260 mV, which is large enough to allow the determination of one in presence of the other. Under the optimum conditions, the anodic peak currents (I _pa) of DPV are proportional to the concentration of UA in the range of 2.0 × 10⁻⁶ to 6.0 × 10⁻⁴ M, with the detection limit of 5.0 × 10⁻⁷ M at a signal-to-noise ratio of 3 (S/N = 3) and to that of AA in the range of 4.0 × 10⁻⁶ to 1.0 × 10⁻³ M, with the detection limit of 8.0 × 10⁻⁷ M (S/N = 3).     

Solvothermal syntheses and crystal structures of two new thiogermanates [M(dap)3]4Ge4S10Cl4 (M?=?Co, Ni) with metal complexes as counterions

Abstract  

Two new transition-metal thiogermanates [M(dap)₃]₄Ge₄S₁₀Cl₄ (M = Co, Ni; dap = 1,2-propanediamine) have been solvothermally synthesized and structurally characterized. The two thiogermanates are isostructural and consist of discrete Ge₄S₁₀⁴⁻ adamantane-like ions, free Cl⁻ ions, and [M(dap)₃]²⁺ cations as counterions. The Ge₄S₁₀⁴⁻ anion is built from corner-sharing connection of four GeS₄⁴⁻ tetrahedra. Although some chalcogenidogermanates have been obtained by use of in situ generated transition-metal complexes as structure-directing agents under mild solvothermal conditions, their anions are usually dimeric [Ge₂Q₆]⁴⁻ (Q = S, Se) species. The new thiogermanates are rare examples of adamantane-like (Ge₄S₁₀⁴⁻) thiogermanates combined with transition-metal complexes. Their optical properties have been investigated by UV–Vis spectra.     

Synthesis of polysilisiquioxane used as core layer material of optical waveguide

Colorless and transparent polysilisiquioxane was synthesized using non-hydrolytic sol–gel process. A high degree of poly-condensation and a lower remnant ratio of Si–OCH₃ were calculated by ²⁹Si NMR and ¹H NMR, respectively. After spin-coating, subsequently UV and thermal curing, free-cracked thin films were obtained. The properties of the free-cracked thin films were measured by a prism coupler and thermal analysis system. The refractive index increased to 1.5495 (1,310 nm TE) and 1.5468 (1,550 nm TE), respectively, with the increasing of phenyltrimethoxysilane content to 20 mol%. Birefringence was below 0.0005. The thermo-optic coefficient was about −2.8 × 10⁻⁴ °C⁻¹. The optical loss was 0.20 dB cm⁻¹ at 1,310 nm and 0.75 dB cm⁻¹ at 1,550 nm, which was very important for core layer material of optical waveguide. The results of Thermo-Gravimetric Analysis indicated an excellent thermal stability. All of these properties imply that it will be a promising core layer material of optical waveguide.     

Electrogeneration of polyluminol and chemiluminescence for new disposable reagentless optical sensors

A performant reagentless electrochemiluminescent (ECL) detection system for H₂O₂ is presented, based on an electropolymerized polyluminol film prepared under near-neutral conditions. Such an original polyluminol electrodeposition is reported for the first time and on a screen-printed electrode (SPE) surface. Electropolymerized luminol acts as an active luminophore of the electrochemiluminescent reaction, as the monomer does. Polymerization conditions have been optimized in order to obtain the best ECL responses to H₂O₂. By performing electrodeposition in a potentiostatic mode, at 425 mV vs. Ag|AgCl, in 0.1 mol L⁻¹ phosphate/0.1 mol L⁻¹ KCl pH 6 and 1 mmol L⁻¹ luminol, with a total charge of 0.5 mC, the linear range for H₂O₂ detection extends from 7.9 × 10⁻⁸ mol L⁻¹ to 1.3 × 10⁻³ mol L⁻¹. Such performant disposable reagentless easy-to-use miniaturized systems based on SPEs should be applicable to the electrochemiluminescent detection of many oxidase-substrate compounds. Figure An original polyluminol electrodeposition process on a screen-printed electrode surface is reported for the first time. The polymeric structure is demonstrated to behave as an electrochemiluminescent luminophore, allowing disposable reagentless easy-to-use optical sensors for hydrogen peroxide detection to be designed.     

Synthesis and characterization of co-precipitated nickel phosphate [Ni3(PO4)2] nanoparticles prepared at varying precursor concentrations

This work investigated the structural, morphological, elemental, optical, and electrochemical characteristics of nickel phosphate nanoparticles co-precipitated at varying molar concentrations. Structural results gave monoclinic crystalline phase with nanorod morphology. EDX plots confirmed deposition of constituent element: nickel, phosphorus and oxygen. The films exhibited good absorbance feature with optical energy band gap values ranging from 1.58 eV to 2.2 eV. Good cyclic reversibility as obtained using 0.1 M of sodium hydroxide as electrolyte. The specific capacitance values of the electrodes ranged from 624.38 F/g to 1017.2 F/g at a scan rate of 1 mV/s. The Ni₃(PO₄)₂ electrode prepared at 0.3 M recorded maximum energy and power densities of 239.49 Wh/kg and 2.52 W/kg respectively. The synthesized samples find potential application in optical and electrochemical devices.     

Silver(I)-selective membrane potentiometric sensor based on two recently synthesized ionophores containing calix[4]arene

Two new PVC membrane electrodes that are highly selective to Ag(I) ions were prepared using (L₁) calyx[4]arene (L₂) as two suitable neutral carriers. The silver(I) ion selective electrodes exhibit a good response for silver ion over a wide concentration range of 1.0 × 10⁻¹ to 4.2 × 10⁻⁶ M (L₁) and 1.0 × 10⁻¹ to 6.5 × 10⁻⁶ M (L₂) with a Nernstian slope of 60 mV per decade (L₁) and 58 mV per decade (L₂) at 25°C, and was found to be very selective, precise, and usable within the pH range 4.0–8.0. They have a response time of <15 s and can be used for at least 3 months without any measurable divergence in potential. The proposed sensors show a fairly good discriminating ability towards Ag⁺ ion in comparison to some hard and soft metal ions. The electrodes were used as indicator electrodes in the potentiometric titration of silver ion and in the determination of Ag⁺ in photographic emulsion and radiographic and photographic films. Published in Russian in Elektrokhimiya, 2009, Vol. 45, No. 7, pp. 862–868. The article is published in the original.     

Preparation and characterization of AuPt alloy nanoparticle–multi-walled carbon nanotube–ionic liquid composite film for electrocatalytic oxidation of cysteine

Gold–platinum (AuPt) alloy particles were fabricated directly on multi-walled carbon nanotubes (MWNT)–ionic liquid (i.e., trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, [P_6,6,6,14][NTf₂]) composite coated glassy carbon electrode (GCE) by electrodeposition method. Scanning electron microscope image showed that they were well-dispersed nanocluster consisting of smaller nanoparticles, and their size was about 70 nm. X-ray diffraction experiment showed that they were single-phase alloy nanomaterial, and the calculated composition was consisting with that obtained by energy dispersive X-ray spectroscopy. The resulting modified electrode (i.e., AuPt–MWNT–[P_6,6,6,14][NTf₂]/GCE) presented high catalytic activity for the electrochemical oxidation of cysteine. The peak potential of cysteine shifted to 0.42 V (versus saturated calomel electrode) in 0.1 M H₂SO₄ and the peak current increased greatly in comparison with that on the corresponding Pt (or Au)–MWNT–[P_6,6,6,14][NTf₂]/GCE. Under the optimized conditions, the oxidation current of cysteine at 0.45 V was linear to its concentration in the range of 5.0 × 10⁻⁷ ∼ 4.0 × 10⁻⁵ M with a sensitivity of 43.8 mA M⁻¹.     

STM and AFM characterization of thin metal oxide films electrodeposited from [P2Mo18O62]6−

Two groups of techniques have been devised for the electrodeposition of new electroactive oxide films from [P₂Mo₁₈O₆₂]⁶⁻. In the first group, two adsorption procedures were used: simple immersion of the electrode in a solution containing 10⁻⁴M [P₂Mo₁₈O₆₂]⁶⁻ in a pH 3.50 medium or cycling of the electrode in this solution in the potential domain of the first three two-electron waves of the heteropolyanion results in surfaces which retain the oxometalate by mere adsorption. Strikingly, during the cycling, it was found that a fourth wave appears in the potential domain of the first three two-electron waves of [P₂Mo₁₈O₆₂]⁶⁻, indicating an evolution of the heteropolyanion in the solution. Such an evolution was also observed with aged solutions. Then, the potential program for the actual modification step was run by cycling either of these electrodes from −0.2 V to −0.87 V vs. SCE in pure supporting electrolyte. Analysis of the STM images of the surfaces show essentially monomers 1.2–1.5 nm in diameter just after adsorption and a sizeable increase of the dimensions of the patterns after modification. The predominant sizes of these aggregates after modification remain in the range 10–12 nm. The second group of techniques consists in a modification of the electrode surface directly in the solution containing the heteropolyanion. A fixed potential as well as cycling prove efficient. Thick films are obtained readily, which are better imaged by tapping mode AFM. An increase of the pH to 4.50, in appropriate conditions, seems to be favourable to the deposition kinetics. The aggregates in the topmost layers are up to 40 nm in diameter and are assembled in interconnected islands. As a whole, these two groups of techniques appear to exert an important influence on the aggregate sizes. The paper demonstrates that these sizes might be relatively well controlled by the choice of experimental conditions. Received: 4 January 2000 / Accepted: 15 February 2000     

Thiolate-bridged Trinuclear Heterobimetallic Complexes [Cd(μ-SPh-4-Me)4{M(PPh3)2}2] (M?=?Cu, Ag) and [Sn(μ-SPh)6(AgPPh3)2]

Abstract  

Reaction of the [Me₄N]₂[Cd(SPh-4-Me)₄] with two equivalents of [M(PPh₃)₂NO₃] afforded the neutral linear trinuclear complexes [Cd(μ-SPh-4-Me)₄{M(PPh₃)₂}₂] (M = Cu 1, Ag 2) in which two [M(PPh₃)₂]⁺ fragments chelate with the opposite edges of a tetrahedral [Cd(SPh-4-Me)₄]²⁻ moiety via the sulfur atoms of the Me-4-PhS⁻ species. Treatment of [Sn(SPh)₄] with two equivalents of [Ag(PPh₃)₂NO₃] gave the neutral linear trinuclear complex [Sn(μ-SPh)₆(AgPPh₃)₂] (3) that is composed of a central distorted SnS₆ octahedron sharing two opposite planes with two slightly distorted AgS₃P tetrahedrons. Complexes 2 and 3 are air and optically stable. Their nonlinear optical absorption and refraction were investigated under the same conditions. The nonlinear optical absorption and refraction of complex 2 were determined to be α ₂ = 3.11 × 10⁻¹¹ m/W and n ₂ = 4.15 × 10⁻¹² esu, respectively. The nonlinear optical absorption and refraction of complex 3 were determined to be α ₂ = 8.36 × 10⁻¹¹ m/W and n ₂ = 1.47 × 10⁻¹¹ esu, respectively.     

Effect of annealing atmosphere on structural,optical and electrical properties of Al-doped Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O thin films

1 at.% Al-doped Zn_1−x Cd _x O (x = 0–8 at.%) thin films were prepared on glass substrates by sol–gel method. The codoping films retained the hexagonal wurtzite structure of ZnO, and showed preferential c-axis orientation. The effect of annealing ambient (in vacuum and nitrogen) on the optical and electrical properties of (Cd,Al)-codoped ZnO films were investigated using transmission spectra and electrical measurements. The transmittances of the codoping films were obviously degraded by vacuum annealing to 50–60 %, but enhanced to 70–80 % after nitrogen annealing. The carrier concentration and Hall mobility both increased, and resistivity decreased with narrowing band gap of Al-doped Zn_1−x Cd _x O, below different critical concentrations x = 4 % (in vacuum) and x = 6 % (in nitrogen). It is revealed that the conductivity is also improved by Cd doping along with band gap modification. The variations in optical and electrical properties are ascribed to both the changes of the crystallinity and concentration of oxygen vacancies under different ambient. In view of transmittance and conductivity, nitrogen annealing might be a more effective post-annealing way than vacuum annealing for our (Cd,Al)-codoped ZnO films to meet the requirements of transparent conducting oxide (TCO).