Extinction coefficient of free-standing chitosan films determined from partially coherent transmittance spectra

Domínguez-Gómez, Amos B; Mauricio-Sánchez, Reina Araceli; Mendoza-Galván, A.

doi:10.1016/j.optmat.2018.07.059

Cited by 8 publications

(5 citation statements)

References 32 publications

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“…Notably, an upward trend in α is observed as hν increases from 3.8 eV to 5.4 eV, attributed to the absorbing nature of TDEC particles present in the composite films 59 . The absorption edge, indicating the onset of absorption, can be discerned by extrapolating the steeper portion of the absorption curve to the corresponding hν value, thereby providing insight into the material's band‐gap energy ( E g ) 60 . Remarkably, all intersection points of the film's absorption curves lie within the visible region, indicating their potential for optical applications 61 .…”

Section: Resultsmentioning

confidence: 99%

“…thereby providing insight into the material's band-gap energy (E g ). 60 Remarkably, all intersection points of the film's absorption curves lie within the visible region, indicating their potential for optical applications. 61 Furthermore, the absorption edge shifts toward higher wavelengths with increasing TDEC dosage, indicating a reduction in E g due to the incorporation of TDEC into the chitosan matrix.…”

Section: Morphological Studiesmentioning

confidence: 90%

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Modified eco‐friendly and biodegradable chitosan‐based sustainable semiconducting thin films

Lokesh Kumar,

Servesh,

Sunitha

et al. 2024

Polymers for Advanced Techs

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Semiconducting materials are pivotal in various fields, such as solar cells, LEDs, photovoltaic cells, etc. A nature‐friendly chitosan is a good film‐forming, water‐soluble polymer that is modified to a small band‐gap polymer for various optoelectronic applications. Choline chloride:ethylene glycol:glycerin (1:1:1) deep eutectic solvent (DES)‐modified activated carbon is incorporated into the chitosan matric and this composite is fabricated into thin films via spin coating methodology. The obtained films are subjected to multiple studies such as scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy, and UV–vis spectroscopy to perceive the thin‐films microstructure, morphology, conductance, band gap, and optical nature. The integration of DES‐modified activated carbon has significantly improved the charge transfer capacity of chitosan by reducing the band gap from 4.0 to 2.0 eV. These notable characteristics exhibited by the modified films can be key to sustainable semiconducting materials and have the potential to transform several optoelectronic applications.

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Section: Resultsmentioning

confidence: 99%

Section: Morphological Studiesmentioning

confidence: 90%

Modified eco‐friendly and biodegradable chitosan‐based sustainable semiconducting thin films

Lokesh Kumar,

Servesh,

Sunitha

et al. 2024

Polymers for Advanced Techs

View full text Add to dashboard Cite

show abstract

“…Эта особенность может оказывать существенное влияние на измеряемые спектры отражательной R(λ) и пропускательной T (λ) способностей исследуемой структуры. В частности, частичную когерентность излучения необходимо учитывать при решении обратных задач спектрофотометрии для слоев, расположенных на плоскопараллельных слабо поглощающих подложках [1][2][3][4][5][6][7][8][9][10][11][12]. В работах [1,2,5,7,[9][10][11] используются различные варианты феноменологического подхода, в котором в исследуемой плоскопараллельной структуре выделяются так называемые когерентные и некогерентные однородные слои [9].…”

Section: Introductionunclassified

“…В [3,4,6,12] с целью учета интерференции лучей различного порядка в окружающем структуру пространстве в рассмотрение различными способами вводится комплексная степень их когерентности γ. Однако появление двух дополнительных неизвестных в виде вещественной и мнимой частей γ в зависимостях R(λ) и T (λ) [3,4,6,12] существенно усложняет решение обратных задач спектрофотометрии.…”

Section: Introductionunclassified

Спектроскопия Слоев На Плоскопараллельных Подложках

Сотский¹,

Михеев²,

Стаськов³

et al. 2020

Журнал Технической Физики

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Integral expressions for the reflectance and transmittance spectra of the structure consisted of two thin layers deposited on opposite faces of a plane-parallel substrate at oblique illumination of the structure with partially coherent light are obtained. As a result of the asymptotic analysis of the integrals, approximate analytical formulae are established for calculating the indicated spectra, convenient for use in solving inverse spectrophotometry problems. An aluminum doped zinc oxide layer deposited on a glass substrate is studied. The spectra of the refractive index and absorption coefficient of the layer and the substrate, as well as the thickness of the layer, are determined by processing the reflectance and transmission spectra of the structure, measured for s- and p- polarized waves at two angles of light incidence. The found parameters are used in computational experiments to estimate the applicability limits of the formulated approximations.

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confidence: 99%

Supplementary document for Effective absorption coefficient and effective thickness in attenuated total reflection spectroscopy - 5047769.pdf

Mendoza,

Méndez-Lara,

Mauricio-Sánchez

et al. 2021

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Casting of chitosan films. Chitosan films were cast as in our previous works with slight variations in the processing parameters [1,2]. Chitosan of medium molecular weight from shrimp shells, deacetylation degree of 75-85%, and viscosity 200-800 cps as specified by the supplier (Sigma Aldrich) and acid acetic (J. T. Baker) were used as received. The films were cast by dissolving 1.5% w/w of chitosan in 1% w/w aqueous acetic acid solution with continuous stirring for 24 h to promote dissolution. Then, the solution was filtrated to separate insoluble matter. Once filtration was done, 2.5 ml of solution was poured into a petri dish of diameter 60 mm and allowed to evaporate at 50 °C for 16 h in a conventional oven to obtain a chitosan acetate film. The film was stored at 25 °C in a relative humidity 44% for four days to achieve neutralization as reported in our previous work [1]. In this way a chitosan film of 4.32 μm in thickness suitable for FTIR transmittance measurements was obtained. For ellipsometry measurements stiffer samples are required. A solution prepared as above was left to concentrate for two months. Then 8 ml of the solution was poured in a petri dish and dried at 50 °C for 32 h. In this way, a film of about 60 μm in thickness was obtained.Characterization techniques. FTIR measurements were performed using a Spectrum GX system (Perkin Elmer) in the range 500-4000 cm -1 with resolution 4 cm -1 and with averaging over 24 scans. For attenuated total reflection (ATR) spectra we used a MIRacle accessory (PIKE) equipped with a diamond crystal of refractive index 2.4 with a nominal angle of incidence of 45°. A pressure clamp allowing a maximum pressure of 3000 psi as specified by the supplier was used to brought in contact the diamond crystal and solid

show abstract

Extinction coefficient of free-standing chitosan films determined from partially coherent transmittance spectra

Cited by 8 publications

References 32 publications

Modified eco‐friendly and biodegradable chitosan‐based sustainable semiconducting thin films

Modified eco‐friendly and biodegradable chitosan‐based sustainable semiconducting thin films

Спектроскопия Слоев На Плоскопараллельных Подложках

Supplementary document for Effective absorption coefficient and effective thickness in attenuated total reflection spectroscopy - 5047769.pdf

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