scholarly journals Narrowband Spontaneous Emission Amplification from a Conjugated Oligomer Thin Film

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 232
Author(s):  
Mohamad S. AlSalhi ◽  
Mamduh J. Aljaafreh ◽  
Saradh Prasad

In this paper, we studied the laser and optical properties of conjugated oligomer (CO) 1,4-bis(9-ethyl-3-carbazo-vinylene)-9,9-dihexyl-fluorene (BECV-DHF) thin films, which were cast onto a quartz substrate using a spin coating technique. BECV-DHF was dissolved in chloroform at different concentrations to produce thin films with various thicknesses. The obtained results from the absorption spectrum revealed one sharp peak at 403 nm and two broads at 375 and 428 nm. The photoluminescence (PL) spectra were recorded for different thin films made from different concentrations of the oligomer solution. The threshold, laser-induced fluorescence (LIF), and amplified spontaneous emission (ASE) properties of the CO BECV-DHF thin films were studied in detail. The ASE spectrum was achieved at approximately 482.5 nm at a suitable concentration and sufficient pump energy. The time-resolved spectroscopy of the BECV-DHF films was demonstrated at different pump energies.

2021 ◽  
Vol 63 (8) ◽  
pp. 778-782
Author(s):  
Tülay Yıldız ◽  
Nida Katı ◽  
Kadriye Yalçın

Abstract In this study, undoped semiconductor ZnO thin film and Bi-doped ZnO thin films were produced using the sol-gel spin coating method. By changing each parameter of the spin coating method, the best conditions for the formation of the film were determined via the trial and error method. When the appropriate parameter was found, the specified parameter was applied for each film. The structural, superficial, and optical properties of the films produced were characterized via atomic force microscope (AFM), UV-visible spectroscopy, and Fourier transform infrared (FTIR), and the effects of Bi dopant on these properties were investigated. When the morphological properties of the undoped and Bi-doped ZnO films were examined, it was observed that they had a structure in a micro-fiber shape consisting of nanoparticles. When the surface roughness was examined, it was observed that the surface roughness values became larger as the rate of Bi dopant increased. By examining the optical properties of the films, it was determined that they were direct band transition materials and Bi-doped thin films were involved in the semiconductor range. In addition, optical properties changed positively with Bi dopant. Since Bi-doped ZnO thin film has a wide bandgap and good optical properties, it is a material that can be used in optoelectronic applications.


2017 ◽  
Vol 07 (04) ◽  
pp. 1750024 ◽  
Author(s):  
Stephen Lourduraj ◽  
Rayar Victor Williams

Thin films of iron (Fe)-doped titanium dioxide (Fe:TiO[Formula: see text] were prepared by sol–gel spin coating technique and further calcined at 450[Formula: see text]C. The structural and optical properties of Fe-doped TiO2 thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV–vis) and atomic force microscopic (AFM) techniques. The XRD results confirm the nanostructured TiO2 thin films having crystalline nature with anatase phase. The characterization results show that the calcined thin films having high crystallinity and the effect of iron substitution lead to decreased crystallinity. The SEM investigations of Fe-doped TiO2 films also gave evidence that the films were continuous spherical shaped particles with a nanometric range of grain size and film was porous in nature. AFM analysis establishes that the uniformity of the TiO2 thin film with average roughness values. The optical measurements show that the films having high transparency in the visible region and the optical band gap energy of Fe-doped TiO2 film with iron (Fe) decrease with increase in iron content. These important requirements for the Fe:TiO2 films are to be used as window layers in solar cells.


2012 ◽  
Vol 581-582 ◽  
pp. 514-518
Author(s):  
Hong Zhu ◽  
Zhi Jun Guo ◽  
Wein Duo Yang ◽  
Wein Feng Chang

This study investigated the structure, microstructure and optical properties of the highly-oriented lead barium titanate (Pb1-xBaxTiO3, PBT) thin films prepared on MgO (100) substrate by a nonaqueous sol-gel process. The film precursor was synthesized by the modified sol-gel processing from lead acetate, barium acetate, and titanium isopropoxide, acetylacetone as chelating agent, and ethylene glycol as solvent. This stable precursor was formed by acetylacetone chelating with titanium isopropoxide and then mixing the solution of the acetates. The spin-coating technique was used to deposit the PBT films on MgO (100) substrate with different barium contents and various spin-coating numbers, respectively. X-ray diffraction was employed to study the crystal structure of the thin film and field emission scanning electron microscopy was used to characterize the microstructure of the films. Optical properties of the thin films were investigated by Ultraviolet-visible spectrophotometer. All films exhibited a (100) preferred orientation, especially the PB0.5T (3-coating layers) thin film. In the optical properties, the adsorption wavelength shifted to the ultraviolet region with increasing barium.


2015 ◽  
Vol 1109 ◽  
pp. 419-423
Author(s):  
C.H. Rosmani ◽  
A.Z. Zainurul ◽  
M. Rusop ◽  
S. Abdullah

The polymer of poly (3-hexylthiophene) was active layer in application such as solar cells. In this paper, P3HT has been chosed to know the effect of temperature onto P3HT. The optical properties of P3HT were measured by using photoluminescence spectroscopy (PL) and UV-Vis measurement. The polymer of P3HT has been spin coated on the glass by using spin-coating method for thin films produced. The temperature was measured start at 60°C to 180 o C. From PL result the peak was exist at range 500-600 nm and started moved to left side when temperature increase. The UV-Vis result showed at range 400-500 nm towards to blue shifted. After heat treatment, the optical absorption spectra for the thin film of P3HT on the glass showed a distinct red-shifted with developing vibronic features of P3HT and the quenched photoluminescence (PL) spectrum was considerably restored .Keywords: P3HT; temperature; Uv-Vis; photoluminescence; PL; I-V


2019 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
KOMARAIAH DURGAM ◽  
RADHA EPPA ◽  
REDDY M. V. RAMANA ◽  
KUMAR J. SIVA ◽  
R. SAYANNA ◽  
...  

Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.


2011 ◽  
Vol 13 ◽  
pp. 87-92 ◽  
Author(s):  
M.S.P Sarah ◽  
F.S. Zahid ◽  
M.Z. Musa ◽  
U.M. Noor ◽  
Z. Shaameri ◽  
...  

The photoconductivity of a nanocomposite MEH-PPV:TiO2 thin film is investigated. The nanocomposite MEH-PPV:TiO2 thin film was deposited on a glass substrate by spin coating technique. The composition of the TiO2 powder was varied from 5 wt% to 20 wt% (with 5 wt% interval). The concentration of the MEH-PPV is given by 1 mg/1 ml. The current voltage characteristics were measured in dark and under illumination. The photoconductivity showed increment in value as the composition of the TiO2 is raised in the polymer based solution. The absorption showed augmentation as the amount of TiO2 is increased. The escalation of the current voltage is then supported by the results of surface morphology.


2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Mohammad Hossein Habibi ◽  
Mohammad Khaledi Sardashti

Glass plate-supported nanostructure ZnO thin films were deposited by sol-gel spin coating. Films were preheated at275∘Cfor 10 minutes and annealed at 350, 450, and550∘Cfor 80 minutes. The ZnO thin films were transparent ca 80–90% in visible range and revealed that absorption edges at about 370 nm. Thec-axis orientation improves and the grain size increases which was indicated by an increase in intensity of the (002) peak at34.4∘in XRD corresponding to the hexagonal ZnO crystal. The photocatalytic degradation of X6G an anionic monoazo dye, in aqueous solutions, was investigated and the effects of some operational parameters such as the number of layer and reusability of ZnO nanostructure thin film were examined. The results showed that the five-layer coated glass surfaces have a very high photocatalytic performance.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ateyyah M. Al-Baradi ◽  
Ahmed A. Atta ◽  
Ali Badawi ◽  
Saud A. Algarni ◽  
Abdulraheem S. A. Almalki ◽  
...  

Abstract In the current work, the optical properties of tin oxide thin films have been tailored via gamma irradiation for energy applications. The effect of Gamma radiation (50, 100, 150, 200 and 250 kGy) on the microstructural, absorption and oscillator parameters of SnO2 thin films has been investigated. XRD results reveal that the SnO2 films have the symmetry of the space group P42/mnm belonging to the tetragonal system. The crystallite size of γ-irradiated SnO2 thin film slightly increases as the irradiation dose increases. The allowed optical band gaps are estimated by applying various methods such as Tauc’s method, derivation of absorption spectrum fitting and absorption spectrum fitting approaches. The dispersion parameters are extracted from the dispersion curve of the real part of the refractive index. The single-effective-oscillator and Drude models for free charge carrier absorption are applied to obtain the dispersion parameters before and after γ-irradiation.


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