Correlation between the static refractive index and the optical bandgap: Review and new empirical approach

2021 ◽  
pp. 413246
Author(s):  
Hosam M. Gomaa ◽  
I.S. Yahia ◽  
H.Y. Zahran
Keyword(s):  
Refractive Index ◽  
Optical Bandgap ◽  
Empirical Approach ◽  
Static Refractive Index

CORONENE ORGANIC FILMS: OPTICAL AND SPECTRAL CHARACTERISTICS UNDER ANNEALING TEMPERATURE INFLUENCES

2021 ◽  
pp. 2150081
Author(s):  
ERMAN ERDOGAN
Keyword(s):  
Refractive Index ◽  
Annealing Temperature ◽  
Film Growth ◽  
Low Cost ◽  
Spectral Characteristics ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Optical Bandgap ◽  
Dielectric Constants ◽  
Optical Parameters

In this study, spin coating, which is a chemical film layer thin film deposition method, was used for coronene films that were grown on Si substrates annealed at 325, 350 and 375[Formula: see text]K to examine the impacts on the optical properties of films. This method allows for easy control of the deposition parameters such as concentration, temperature and time as well as enables the film growth at low cost. Optical (UV–Vis) spectral measurements in the wavelength range from 200[Formula: see text]nm to 800[Formula: see text]nm were used to extract the bandgap information and to calculate various optical parameters of the spin-coated coronene films. The electronic transitions on the absorption of photons of suitable energy are of indirect allowed type. The corresponding optical bandgap ([Formula: see text]) was determined. Complex dielectric constants, dissipation factor, optical and electrical conductances and refractive index of coronene films were analyzed as a function of temperature. As the film annealing temperature was increased, the dielectric constants and the refractive index values increased, whereas the optical bandgap and electrical and optical conductivity values decreased.

scholarly journals Determination of the complex refractive index and optical bandgap of CH3NH3PbI3thin films

2017 ◽  
Vol 121 (17) ◽  
pp. 173104 ◽  
Author(s):  
J. A. Guerra ◽  
A. Tejada ◽  
L. Korte ◽  
L. Kegelmann ◽  
J. A. Töfflinger ◽  
...  
Keyword(s):  
Refractive Index ◽  
Complex Refractive Index ◽  
Optical Bandgap

scholarly journals Characterization of As-Prepared (PMMA-PVA)/CuO-NPs Hybrid Nanocomposite Thin Films

2021 ◽  
Author(s):  
Ahmad Alsaad ◽  
Ahmad Ahmad ◽  
Abdul Raouf Al Dairy ◽  
Issam A. Qattan ◽  
Shatha Al Fawares ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
Polymeric Thin Films ◽  
Cuo Nps ◽  
Wide Range ◽  
Nanocomposite Thin Films ◽  
Optical Bandgap Energy

We report the synthesis and characterization of Poly Methyl-Meth-Acrylate (PMMA)/Poly vinylalcohol (PVA) polymeric blend doped with different concentrations of Copper oxide (CuO) nanoparticles (NPs). The (PMMA-PVA)/CuO nanocomposite hybrid thin films (wt. % = 0%, 2%, 4%, 8%, and 16%) of CuO NPs are deposited on glass substrates via dip-coating technique. The transmittance (T%), reflectance (R%), the absorption coefficient (α), the optical constants [refractive index (n), extinction coefficient (k)], optical dielectric functions [ɛ',ɛ''] are investigated and interpreted. Tauc, Urbach, Spitzer-Fan, and Drude models are employed to calculate the optical bandgap energy (Eg) and the optoelectronic parameters of the nanocomposite thin films. The refractive index and optical bandgap energy of of (PMMA-PVA) polymeric thin film are found to be (1.5 to 1.85) and 4.101 eV, respectively. Incorporation of specific concentrations of CuO-NPs in (PMMA-PVA) polymeric thin films leads to a noticeable decrease in the optical bandgap energy and to an increase of the refractive index. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) transmittance spectra are measured and analyzed for undoped and doped polymeric thin films to pinpoint the major vibrational modes in the spectral range (500 and 4000 cm-1), as well as, the nature of network bonding in both systems. Thermal stability of thin films is investigated by performing thermogravimetric analysis (TGA). The TGA thermograms confirm that both doped polymeric thin films are thermally stable at temperatures below 110°C which enables them to be attractive for a wide range of optical and optoelectronic applications. Our results indicate that optical, vibrational and thermal properties of both polymeric thin films can be tuned for specific applications by the appropriate corporation of particular concentrations of CuO-NPs.

A NOVEL METHOD FOR PRODUCING NANOSTRUCTURED CdSe THIN FILM

2019 ◽  
Vol 27 (07) ◽  
pp. 1950175 ◽  
Author(s):  
İSHAK AFŞIN KARİPER
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Refractive Index ◽  
Film Thickness ◽  
Sem Analysis ◽  
Optical Bandgap ◽  
Cdse Thin Film ◽  
Glass Substrates ◽  
Commercial Glass ◽  
Ph Level

In this study, we produced Cadmium selenide (CdSe) crystalline thin film on commercial glass substrates via chemical bath deposition. Transmittance, absorbance, refractive index and optical bandgap of thin films were examined by UV/vis spectrum. XRD revealed a hexagonal form. The pH level of the baths in which CdSe thin films were deposited varied and optical and structural properties of the resulting thin films were analyzed. SEM analysis was used for surface analysis. Some features of the films were supposed to change with pH and these properties were investigated by testing different pH levels, which were 8, 9, 10 and 11. The variation of the optical bandgap changed between 1.60 and 1.75[Formula: see text]eV, according to the pH of deposition bath. Film thickness varied from 60[Formula: see text]nm to 93[Formula: see text]nm, with the variation of deposition bath’s pH. Moreover, it has been found that refractive index values were also changed with film thickness; these were calculated as 2.28, 2.19, 2.22 and 2.36 for 93.27, 60.97, 61.09 and 60.18[Formula: see text]nm, respectively. Dielectric constant also varied with refractive index, taking values 0.85, 0.75, 0.78, 0.93 for refractive indexes 2.28, 2.19, 2.22 and 2.36, respectively.

scholarly journals Effect of co-doping on dielectric function spectra and static refractive indices of single-walled carbon nanotubes: A first principles study

2017 ◽  
Vol 95 (12) ◽  
pp. 1194-1199 ◽  
Author(s):  
Deepa Sharma ◽  
Neena Jaggi
Keyword(s):  
Carbon Nanotubes ◽  
Refractive Index ◽  
Dielectric Function ◽  
Single Walled Carbon Nanotubes ◽  
Refractive Indices ◽  
Single Walled Carbon ◽  
Co Doping ◽  
Static Refractive Index ◽  
Walled Carbon Nanotubes ◽  
Co Doped

This paper details a density functional theory (DFT) based ab initio study on the effect of co-doping on the dielectric function spectra and refractive indices of single-walled carbon nanotubes (SWCNTs). Dielectric function spectra of a pristine (8,0) SWCNT; (8,0) SWCNT co-doped with aluminum (Al) and phosphorus (P); (8,0) SWCNT co-doped with Al, P, and nitrogen (N); (9,0) SWCNT doped with Al; and (9,0) SWCNT co-doped with Al and boron (B) have been calculated using DFT-based Cambridge sequential total energy package (CASTEP) code. Polarized and unpolarized light as well as light through polycrystalline media have been considered. Analysis involves calculation and comparison of static refractive indices of the pristine and co-doped SWCNTs. Co-doping with Al and P results in a substantial increase in the value of the static refractive index while co-doping of Al, N, and P results in a reduction in the value of static refractive index though it does not fall lower than that of the pristine SWCNT. Thus, it can be concluded that co-doping with atoms of different combinations of elements can be evolved as a novel and effective tool for tuning the dielectric function and static refractive index values of SWCNTs. It will prove to be highly significant for effective designing of various sensitive optical devices using SWCNTs.

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