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Post-annealing effects on the structural and optical properties of nickel vanadate thin films.
(2026-05-15)
Nedkun, Piyanooch
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Sangsai, Phannita
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Wongrat, Ekasiddh
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Chaiworn, Panupat
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Tubtimtae, Auttasit
Abstract This research gap is to understand the post-annealing-temperature-dependent structural transition and defect-mediated optical tuning in NiV₂O₆ thin films deposited using a spin-coating technique. By systematically correlating phase evolution, oxygen vacancy formation, and band gap modulation. The as-prepared thin films were annealed at 200 °C, 300 °C, 400 °C, and 500 °C. The annealing temperature of 400 °C was found for an amorphous structure with the band gap of 2.38 eV, which within an appropriate band gap of ∼ 2.3–2.6 eV for photoelectrochemical and electrochromic applications. Tuning of improved crystallinity with structural rearrangement and a lower band gap of 2.10 eV were obtained at 500 °C, which induced the diffusion of oxygen atoms and led to the formation of oxygen vacancies. This provides a clear processing–structure–optical property correlation and offers a simple-thermal route for band gap engineering without additional doping for enhancing the optical efficiency in solar absorber, optoelectronic, and photonic applications, particularly in broadband optical devices.
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Effect of pyrazine in PEDOT:PSS thin films: Structural, optical, optoelectrical, and electrical analysis
(2023-02-01)
Teesetsopon, Pichanan
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Treewut, Pattaraporn
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Sripetch, Sasithorn
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Nasomjai, Piyatida
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Tubtimtae, Auttasit
The pristine PEDOT:PSS and different weight amounts of pyrazine in PEDOT:PSS thin films were prepared using the doctor-blading technique on a borosilicate glass substrate. The structural, optical, and electrical properties of the effect of pyrazine in PEDOT:PSS thin films were presented for the first time of this admixed solution. More accuracy in the surface of thin films was observed by atomic force microscopy (AFM) which revealed the granular deposits on the film surfaces. Some hill shapes and the distribution of agglomerated grains were also observed on the thin films. The PEDOT:PSS with pyrazine has a preferred orientation to be an orthorhombic crystal structure. The crystallite sizes were reduced from 230.40 nm to 101.81 nm for 30–60 mg pyrazine in the PEDOT:PSS. The energy band gap (E<inf>g</inf>) value of pristine PEDOT:PSS is of 3.50 eV with Urbach energy (E<inf>U</inf>) of 336.10 meV. The alteration E<inf>g</inf> values from 3.52 to 3.67 eV was obtained with the estimated E<inf>U</inf> values in the range of 283.16–324.62 meV depends on various amounts of pyrazine. The linear optical parameters, i.e., the refractive index, optical electronegativity, real/imaginary dielectric constants, extinction coefficient, and optical conductivity were investigated and explained by the changes in the formation, nucleation, growth of clusters, and particle arrangement. As the spectrum increased, the highest χ(1), χ(3), and n<inf>2</inf> values were obtained for the 80 mg pyrazine in PEDOT:PSS of 0.110, 2.562 × 10−14 esu, and 6.219 × 10−13 esu, respectively. The electrical conductivity was clearly increased for pyrazine exceeding 40 mg from 1.85 × 102 to 3.84 × 102 S/cm and the figure of merit was in the range of 4.34 × 10−2 to 4.68 × 10−2 Ω−1. Thus, the novelty of this work can show that pyrazine in the range of 40 mg–80 mg is the optimum condition to synthesize non-linear optical (NLO) materials, organic light-emitting diodes (OLEDs), and organic light-emitting transistors (OLETs).
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Structural, optical, and electrical properties via two simple routes for the synthesis of multi-phase potassium antimony oxide thin films
(2022-07-15)
Homcheunjit, Ratchaneekorn
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Pluengphon, Prayoonsak
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Tubtimtae, Auttasit
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Teesetsopon, Pichanan
Multi-phase ternary oxide glass thin films of potassium antimony oxide were synthesized via dip coating (DC) and spray pyrolysis (SP) methods. The growth of thin film was conducted on a non-conductive borosilicate glass substrate. Surface morphology was investigated and showed different characteristics. X-ray diffraction (XRD) analysis revealed the peaks corresponded to the monoclinic KSb<inf>3</inf>O<inf>5</inf> and K<inf>2</inf>Sb<inf>4</inf>O<inf>11</inf> phases. The structural parameter analysis shows that the lower values of micro strain (ε), dislocation density (δ), and stacking fault probability (SF) with higher number (N) of particle in the multi-phase thin film for the spray pyrolysis method confirm slightly larger crystallite size, less crystal imperfection, and less structural disorder. The lower average transmission, absorption, and extinction coefficients resulted to higher refractive index, permittivity, and electrical susceptibility for the sample synthesized by a spray pyrolysis method. In addition, the average energy band gap values (E<inf>g</inf>) of 3.57 and 3.60 eV were obtained for the dip coating and spray pyrolysis methods, respectively. However, the lower R<inf>s</inf> (14.69 × 107 Ω/sq.) with higher σ<inf>h</inf> (85.09 S/cm) and the FOM<inf>(H-HR)</inf> (0.183 Ω-1) of the multi-phase K–Sb–O thin film for the dip coating method were obtained may be due to more interconnections generated at the interface and there are less residual on the surface of thin film.
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Response to comments on the paper, “Effect of low thermal treatment temperatures on the morphological, optical and electrical properties of Sn1-xMnxTe nanocomposite films incorporated with indium cations [Ceram. Int. 45 (2019) 23,203–23215]”
(2020-08-15)
Rukcharoen, Nuengruethai
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Tubtimtae, Auttasit
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Kitisripanya, Nareerat
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Electrochemical performance of Bi2Te3 heterostructure thin film and Cu7Te4 nanocrystals on undoped and In3+-doped WO3 films for energy storage applications
(2020-05-01)
Buathet, Supitchaya
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Simalaotao, Kodchakorn
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Reunchan, Pakpoom
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
We demonstrated the synthesis of undoped and In3+-doped WO<inf>3</inf> as an electron acceptor for energy storage applications, by utilizing the electrochemical S2− insertion/extraction process at the heterostructure of rhombohedral Bi<inf>2</inf>Te<inf>3</inf> thin films and hexagonal Cu<inf>7</inf>Te<inf>4</inf> nanocrystals. The cyclic voltammetry of heterostructured electrodes with and without In3+ doping both showed Faradic pseudo-capacitance behavior based on the oxidation and reduction processes. The largest exchange current density of 3.43 mA/cm2 was obtained for the heterojunction-structured-Bi<inf>2</inf>Te<inf>3</inf> thin films and Cu<inf>7</inf>Te<inf>4</inf> nanocrystals with In3+ doping in the WO<inf>3</inf> electrode. This implies more favorable hydrogen evolution reaction kinetics and higher electrocatalytic activity at the anode. The highest specific capacity of 90.2 mA h/g was obtained at a scan rate of 10 mV/s, with the power density reaching 1.7 kW/kg at the highest energy density value of 18.85 Wh/kg for the In3+-doped electrode. The overall results revealed the inherent properties of the new electrode materials, as well as their potential use in energy storage devices or in future electrochemical energy conversion and storage applications involving hydrogen (or oxygen) evolution reactions.
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Structural, optical and electrochemical performances of undoped and Sn2+-doped Bi2Te3 nanoparticles on WO3 electrodes
(2020-01-01)
Buddeesao, Mirantee
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Raknual, Duanghatai
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Tubtimtae, Auttasit
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
A facile synthesis approach was used to prepare Sn2+-doped Bi<inf>2</inf>Te<inf>3</inf> nanospheres on a WO<inf>3</inf> electrode, and the pseudo-capacitive property was measured for samples prepared with optimum parameters. SEM micrographs revealed that after the Sn2+ doping, the morphology of Bi<inf>2</inf>Te<inf>3</inf> changed from aggregated or network-like nanoparticles to smaller nanospheres with a homogeneous distribution. The X-ray diffraction pattern showed rhombohedral Bi<inf>2</inf>Te<inf>3</inf> coated on the WO<inf>3</inf> electrode. Due to the more abundant electro-active sites and charge carriers that diffused through the electrolyte to the working electrode, the Sn2+-doped Bi<inf>2</inf>Te<inf>3</inf> electrode displayed the highest specific capacity of 41.4 mAh/g at a scan rate 10 mV/s, a power density of 0.63 kW/kg, an energy density of 24.5 Wh/kg, and an LSV breakdown potential of 0.26 V. These materials may be applied in potential pseudo-capacitors and in further energy storage devices.
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Effect of low thermal treatment temperatures on the morphological, optical and electrical properties of Sn1-xMnxTe nanocomposite films incorporated with indium cations
(2019-12-01)
Rukcharoen, Nuengruethai
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Tubtimtae, Auttasit
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Kitisripanya, Nareerat
Amorphous chalcogenide semiconductors have advantageous optical and electrochemical properties, but the influence of the thermal treatment temperature on these properties is not clearly understood. In this study, In3+-incorporated Sn<inf>1-x</inf>Mn<inf>x</inf>Te nanocomposite films were prepared on commercial glass substrates using a solution-based doctor-blading method and low thermal treatment temperatures. The effect of the thermal treatment temperature (50–200 °C) on the optical and electrical properties of the nanocomposite films was investigated. X-ray diffraction results confirmed that an amorphous nanocomposite film was formed at each thermal treatment temperature. However, variation in the optical parameters and electrical performance of the nanocomposite films with the thermal treatment temperature indicated that this temperature should not exceed 150 °C. Optimization of the thermal treatment temperature improved the light-harvesting ability of the nanocomposite films and enhanced the polarization of the incident radiation. These phenomena were caused by an increase in atomic oscillations associated with higher dipole moments in the films. The nanocomposite films subjected to thermal treatment at temperatures below 150 °C also exhibited the highest electrical conductivity. These results will allow the synthesis of improved materials for applications in solar selective surfaces and electro-optical, photovoltaic-thermal, and sensor devices.
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Structural and electrochemical studies of undoped and In3+-doped co-binary Cu2-xTe and Bi2Te3 thin films for aqueous Na–S batteries
(2019-10-01)
Sreerung, Rawita
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Raknual, Duanghatai
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Kitisripanya, Nareerat
WO<inf>3</inf> electrodes coated with co-binary Cu<inf>2-x</inf>Te and Bi<inf>2</inf>Te<inf>3</inf> thin films were fabricated for sodium-sulfur (Na–S) batteries. Film fabrication was controlled by adjusting the pH of the solution and the indium doping concentration. The phases of orthorhombic CuTe and hexagonal Cu<inf>2</inf>Te with rhombohedral Bi<inf>2</inf>Te<inf>3</inf> were formed on the WO<inf>3</inf> electrode. After In3+ doping, In3+ ions act as Frenkel defects in the Cu<inf>2-x</inf>Te structure. This indicated that In3+ ions are located at interstitial sites in the Cu<inf>2-x</inf>Te structure with higher defect creation energy. Furthermore, more interconnected-like nanoparticles and reduced porosity were observed, thereby indicating that indium segregation with grain boundaries presented and contributed to an enhancement of the surface mobility, nucleation density, and a smoother surface. For electrochemical characteristics, a polysulfide solution was used as a redox electrolyte for ion transport. Optimization of the pH and indium concentration attributed to improve the exchange current density (J<inf>0</inf>) and time responses for the colored and bleached states because of faster movement of Na+ and S2− ions during inter/de-intercalation. Furthermore, optimization of the electrode by adjusting the pH and doping with indium is advantageous for both Na–S and rechargeable batteries because of long life cycle, reasonably high power and energy density of 306 W/kg and 9.35 Wh/kg, respectively. The highest specific capacity (C<inf>s</inf>) values of the charge and discharge cycles for In3+-doped electrodes are ∼ 21 and 19 mAh/g, respectively with the coulombic efficiency approximates 100% (average value of ∼96%). This approach may provide a general path for the fabrication of undoped and In3+-doped co-binary Cu<inf>2-x</inf>Te and Bi<inf>2</inf>Te<inf>3</inf> films on WO<inf>3</inf> electrodes and may increase our knowledge regarding Na–S batteries for further performance improvement.
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Copper incorporation in Mn2+-doped Sn2S3 nanocrystals and the resultant structural, optical, and electrochemical characteristics
(2018-08-15)
Noppakuadrittidej, Prae
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Choopun, Supab
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Tubtimtae, Auttasit
Sn<inf>2</inf>S<inf>3</inf> nanocrystals (NCs) with both Mn2+ doping and Cu2+ incorporation were synthesized using a chemical bath deposition method. The Cu2+ ions formed an anorthic Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> structure with E<inf>g</inf> = 1.44 eV, which altered the material's optical and photo/electrochemical properties. After coating the bare Nb<inf>2</inf>O<inf>5</inf> electrode with Mn2+-doped Sn<inf>2</inf>S<inf>3</inf> or Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> NCs, the photoluminescence spectrum was blue-shifted to 411.13 nm from 411.69 nm. Compared to the sample without Cu2+, the Cu2+-incorporated sample showed a slightly stronger emission at the same position, possibly due to disorder in the crystalline structure based on variations at the interface of Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> NCs. Electrochemical analysis showed a lower charge transfer resistance in the Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf>, which is related to its larger electroactive surface area. The larger electroactive surface area is attributed to the Faradaic redox processes at the electrode surface, which suppresses the carrier recombination. The coexistence of Cu2+ and Mn2+ ions shortened the electron transport pathway at the interface and improved the carrier diffusion coefficient and diffusion length, leading to a higher specific capacitance that implies higher energy storage performance. Finally, the I-V characteristics of the Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf>-coated Nb<inf>2</inf>O<inf>5</inf> electrode under various light illumination conditions indicated its better efficiency in photoresponse, electron generation, and charge collection, owing to a superior charge transport mechanism. Detailed results were obtained about the charge dynamics in the as-prepared photo/electrochemical devices with Cu2+ incorporation in the Mn2+-doped SnS<inf>3</inf> electrode.
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Effect of annealing process on the properties of undoped and manganese2+-doped co-binary copper telluride and tin telluride thin films
(2018-04-15)
Kladkaew, Meaunfun
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Samranlertrit, Norasate
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Tubtimtae, Auttasit
The binary semiconductor materials Cu<inf>1.81</inf>Te and SnTe materials, without and with manganese (Mn2+) doping, were prepared by dropping a Cu-Sn-Te solution on a commercial glass substrate to fabricate a co-binary thin film. The characteristics, optical, and electrical properties of undoped and Mn2+-doped Cu<inf>1.81</inf>Te/SnTe thin films were investigated with variations in the annealing process. The XRD results confirmed the films consisted of the co-binary orthorhombic phase materials Cu<inf>1.81</inf>Te and SnTe, and that for all annealing temperatures from 50 to 400 °C an amorphous structure became prevalent in the Mn2+-incorporated co-binary thin films. The optical parameters and electrical performance varied with the annealing temperatures and Mn2+ doping, showing alterations in the properties of the co-binary film. These co-binary thin films have feasibility for real applications in surface analysis, electro-optical materials, solar selective surfaces, and photovoltaic thermal devices.

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