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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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Improvement in fast Na-ion conduction in Na3+xCr xTi2−x(PO4)3 glass–ceramic electrolyte material for Na-ion batteries
(2020-10-01)
Gandi, Shyam Sundar
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Gandi, Suman
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Katari, Naresh Kumar
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
Abstract: In this report, efforts were made to investigate and characterize a variety of compositions in a glass system of general formula Na<inf>3+x</inf>Cr<inf>x</inf>Ti<inf>2−x</inf>(PO<inf>4</inf>)<inf>3</inf> (x = 0, 0.25, 0.5 and 0.75 mol%, designated as NCTP<inf>x</inf>) to optimize their properties for use in Na-ion batteries. Several crystalline phases such as Na<inf>3</inf>Ti<inf>2</inf>(PO<inf>4</inf>)<inf>3</inf> (COD-4106515) (NASICON), Cr<inf>2</inf>O<inf>3</inf> (ICSD-25781) and Cr(PO<inf>3</inf>)<inf>3</inf> (ICSD-39410) are precipitated during the process of crystallization. The microstructures of all the glass and glass–ceramic samples are analyzed using SEM and are correlated with powder XRD to explain the ionic conductivity for a given glass–ceramic sample. Single semicircle in the complex impedance plots clearly suggests that the present NCTP<inf>x</inf> glass samples exhibit a predominantly single-ion conduction mechanism. Electrical conductivity data follow the Arrhenius equation. The power-law exponent ‘s’ is observed to be the lowest (0.70) for the best conducting glass–ceramic sample NTCP<inf>0.5</inf> (4.24 × 10−4 S/cm). The electrical modulus study proves that the conductivity relaxation of NCTP<inf>x</inf> glass–ceramic samples is temperature independent. Scaling behavior in the normalized spectra indicates that frequency-dependent relaxation behavior is unaffected by the temperature. Graphic abstract: [Figure not available: see fulltext.].
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Local structure, electrical and magnetic properties of Fe-doped Sr2(Ni,Mo)O6 double perovskite
(2017-08-01)
Prasatkhetragarn, Anurak
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Sriboonpeng, Chana
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Jantaratana, Pongsakorn
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Vittayakorn, Naratip
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Thammajak, Nirawat
Double perovskite material of 10 mol% Fe-doped Sr<inf>2</inf>(Ni,Mo)O<inf>6</inf> was prepared by solid-state reaction. The NiMoO<inf>4</inf> precursor was first synthesized as a starting material with calcination temperature at 1100 °C in air. Effects of FeO, Fe<inf>2</inf>O<inf>3</inf> and Fe<inf>3</inf>O<inf>4</inf> dopant on phase formation, morphology, electrical and magnetic properties of the specimens were investigated and discussed. The XRD technique was used to analyze the phase formation of the samples. It can be clearly seen that phase formation of pure Sr<inf>2</inf>(Ni,Mo)O<inf>6</inf> indicated the cubic phase structure, while the tetragonal phase was found with FeO, Fe<inf>2</inf>O<inf>3</inf> and Fe<inf>3</inf>O<inf>4</inf> dopant. All XANES spectra were collected at the ambient temperature and atmospheric pressure. The result demonstrated that the oxidation state of Fe is 3+, indicating the occurrence of γ-Fe<inf>2</inf>O<inf>3</inf> phase for all samples. In addition, the room temperature ferroelectric and ferromagnetic properties were determined using a simple Sawyer–Tower circuit (at fixed measuring frequency of 50 Hz) and Vibrating Sample Magnetometer (VSM), respectively. The maximum ferroelectric and ferromagnetic properties were seen with Fe<inf>2</inf>O<inf>3</inf> dopant. Interestingly, the ferroelectric and ferromagnetic properties of Sr<inf>2</inf>(Ni,Mo)<inf>0.9</inf>Fe<inf>0.1</inf>O<inf>6</inf> ceramics were affected by iron oxide doping.
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Comparative study of non-annealing and annealing on properties of ITO deposited by RF magnetron sputtering
(2015-01-01)
Khlayboonme, S. Tipawan
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Warawoot, Thowladda
A comparison of the properties for two ITO thin films was performed. The two films were as follows - as-deposited and annealed ITO films. The influence of annealing on the structural, morphological, electrical, and optical properties was studied. The post-annealing treatment was done at a temperature of 400 for 1 h in air. The ITO thin films were deposited onto glass substrates by RF magnetron sputtering of a ceramic In<inf>2</inf>O<inf>3</inf>: SnO<inf>2</inf> target in pure argon atmosphere at a low base pressure of <10-6 mbar and a RF power of 50 W. The films were characterized by XRD, FTIR, contact angle measurements, FE-SEM combined with EDX, Halleffect measurements and UV-Vis transmission spectroscopy. The ITO films showed a crystalline structure with a predominant orientation (400) and its intensity was increased after the film was annealed. The structure of the annealed film became reformed in more perfect columnar structure. The annealed film showed a decrease in contact angle and increase in FTIR spectra intensity. The annealing induced more tin incorporated into the film from 0.51 to 2.62 at%. The resistivity decreased from 2.7×10-3 to 1.1×10-3 Ω cm with increasing mobility from 7.5 to 27.5 cm2 V-1 s-1 but decreasing carrier concentration from 3.0×1020 to 2.0 × 1020 cm-3. The optical band gap increased from 3.43 to 3.50 eV. All films showed highly transparency (×85%) in the visible light region. Compared with the non-annealed ITO film, the air-annealed ITO film revealed the better properties except for carrier concentration.
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Electrical properties of dye-doped colour tunable organic light emitting diode
(2012-08-01)
Khantham, Sirintra
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Tunhoo, Benchapol
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Onlaor, Korakot
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Thiwawong, Thutiyaporn
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Nukeaw, Jiti
In this work, we report on the electrical properties of dye-doped colour tunable organic light-emitting diode (OLED). The device structure is glass substrate/indium tin oxide/N,N′-di(naphthalen-1-yl)-N,N′-diphenyl-benzidine (NPB) 30nm/Alq <inf>3</inf>:DCM 50nm/Aluminum (Al) 150nm where NPB is the hole transport layer. Alq <inf>3</inf>:DCM is the emitting layer which made of tris(8-hydroxyquinoline) aluminium (Alq <inf>3</inf>) doped with 4-(Dicyanomethylene)-2-methyl-6-(4-dimethyl-aminostyryl)-4H-pyran (DCM) organic dye. The influence of doping concentration has been investigated by current density-voltage measurement, luminance intensity-voltage characteristic, electroluminescence (EL) and impedance spectroscopy, respectively. The EL spectrum exhibits the shifted of peak position from green to red region. The threshold voltage of the device decreased at the low DCM doping concentration (1wt.%), in contrast, when the increase in the doping concentrations then the threshold voltage will be increased. The highest luminance intensity and lowest turn-on voltage of OLED can be observed at doping concentration about of 1wt.% of DCM. The impedance characteristics of the dye-doped OLED can be modelled by simply adopting the conventional equivalent circuit with the simple combination of resistors and capacitors network. © 2012 Canadian Society for Chemical Engineering.
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Electrical properties of Al-doped CdO thin films prepared by thermal evaporation in vacuum
(2012-05-08)
Wongcharoen, Ngamnit
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Gaewdang, Thitinai
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Wongcharoen, Tiparatana
In this work, thin films of undoped and Al-doped CdO with 3, 5, 7 and 9 wt.% were prepared by thermal evaporation in vacuum on glass substrate. From XRD patterns, doping CdO films with Al up to 7 % causes small reduction in the intensity of the (200) plane, while small increase is observed in the intensity of (111) plane. However, intensity of all peaks rapidly decreases for the films with high Al content (9 %). The formation of tubular nanostructures of undoped and Al doped-CdO films was observed by SEM technique. Energy gap value of the films was evaluated from the optical transmission spectra in the spectral region 300-1000 nm. The best values of electrical conductivity, Hall mobility and electron concentration were obtained in the films with 5% Al doping. Temperature dependent resistivity measurements of the films doped with Al at 3, 5 and 7 % showed the metal-semiconductor transition around 100, 150 and 205 K respectively, which is rationalised by localisation of degenerate electrons in a weak-localisation regime. It was also found that the transition temperature is dependent on the Al concentration and is related to the increase in disorder induced by dopant addition. © 2011 Published by Elsevier Ltd.
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Investigations on chemically deposited Cd1-xZnxS thin films with low Zn content
(2005-12-01)
Gaewdang, Ng
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Gaewdang, T.
Thin films of Cd<inf>1-x</inf>Zn<inf>x</inf>S (0 ≤ x ≤ 0.8) were deposited on glass substrates by the chemical bath deposition technique. The as-deposited films were exposed to a stream of slowly flowing nitrogen at annealing temperature ranging 100-500 °C. XRD patterns of as-deposited Cd<inf>1-x</inf>Zn<inf>x</inf>S over all mixture ratio values showed the cubic zincblende structure of which reflection peaks associated to (111), (220) and (311) planes were clearly identified. However, XRD characteristics of hexagonal wurtzite structure appeared at annealing temperature beyond 400 °C. From scanning electron microscope, the as-deposited films were formed by different sizes of clusters of grains of which average grain size smaller than 50 nm was observed. The increase in mixture ratio value in the starting solution was found to produce a decrease in the grain size. Energy gap value of annealed films, which is obtained from optical transmission measurements, seems to shift to lower energy as the annealing temperature increases. Electrical sheet resistance of the films, performed in the darkness and under illumination conditions by using a halogen lamp, as a function of annealing temperature was also investigated. The variation of energy gap of thin films with annealing temperature was discussed by employing quantum size effect phenomena. © 2005 Elsevier B.V. All rights reserved.
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In vivo electrical conductivity of hepatic tumours
(2003-01-01)
Haemmerich, Dieter
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Staelin, S. T.
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Tsai, J. Z.
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Tungjitkusolmun, S.
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Mahvi, D. M.
Knowledge of electrical tissue conductivity is necessary to determine deposition of electromagnetic energy and can further be used to diagnostically differentiate between normal and neoplastic tissue. We measured 17 rats with a total of 24 tumours of the K12/TRb rat colon cancer cell line. In each animal we measured in vivo hepatic tumour and normal tissue conductivity at seven frequencies from 10 Hz to 1 MHz, at different tumour stages between 6 and 12 weeks after induction. Conductivity of normal liver tissue was 1.26 ± 0.15 mS cm-1 at 10 Hz, and 4.61 ± 0.42 mS cm-1 at 1 MHz. Conductivity of tumour was 2.69 ± 0.91 mS cm-1 at 10 Hz, and 5.23 ± 0.82 mS cm-1 at 1 MHz. Conductivity was significantly different between normal and tumour tissue (p < 0.05). We determined the percentage of necrosis and fibrosis at the measurement site. We fitted the conductivity data to the Cole-Cole model. For the tumour data we determined Spearman's correlation coefficients between the Cole-Cole parameters and age, necrosis, fibrosis and tumour volume and found significant correlation between necrosis and the Cole-Cole parameters (p < 0.05). We conclude that necrosis within the tumour and the associated membrane breakdown is likely responsible for the observed change in conductivity.

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