Effect of cycle numbers on the structural, linear and nonlinear optical properties in Fe2O3 thin films deposited by SILAR method

Erken Ozge 한국물리학회 2022 Current Applied Physics Vol.34 No.-

Fe2O3 thin films were deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method onto glass substrates at different cycle numbers to investigate structural, linear and nonlinear optical properties. X-Ray Diffraction (XRD) analysis revealed that the Fe2O3 thin films have a non-crystalline nature. The morphological properties of the films were investigated by Field Emission-Scanning Electron Microscopy (FE-SEM) and the results show that the films’ surfaces are porous. The linear and nonlinear optical parameters were evaluated and analyzed by using transmittance and absorbance measurements. For these measurements, UV–Vis spectroscopy at room temperature was used. The refractive index values were calculated in the range of 1.45–3.23 for visible region (400–700 nm). Obtained results reveal that direct optical band gap changed between 2.62 and 2.68 eV and indirect optical band gap changed between 1.67 and 1.77 eV. Additionally, optical electronegativity, optical dielectric constants, surface and volume energy loss functions, nonlinear refractive index, linear optical susceptibility, third-order nonlinear optical susceptibility, optical and electrical conductivity, and loss tangent values were calculated and discussed in detail. It was found that each parameter studied is dependent on the cycle numbers. Also, it can be stated that Fe2O3 thin films are promising candidate for solar cells and optoelectronic device technology.

Controlling of the Optical Properties of the Solutions of the PTCDI-C8 Organic Semiconductor

Erman Erdoğan,Bayram Gündüz 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

N,N′-Dioctyl-3,4,9,10 perylenedicarboximide (PTCDI-C8) organicsemiconductor have vast applications in solar cells, thermoelectricgenerators, thin film photovoltaics and many other optoelectronicdevices. These applications of the materials are based on their spectraland optical properties. The solutions of the PTCDI-C8 for differentmolarities were prepared and the spectral and optical mesaurementswere analyzed. Effects of the molarities on optical properties wereinvestigated. Vibronic structure has been observed based on theabsorption bands of PTCDI-C8 semiconductor with seven peaks at2.292, 2.451, 2.616, 3.212, 3.851, 4.477 and 4.733 eV. The importantspectral parameteres such as molar/mass extinction coefficients,absorption coefficient of the PTCDI-C8 molecule were calculated. Optical properties such as angle of incidence/refraction, optical bandgap, real and imaginary parts of dielectric constant, loss factor andelectrical susceptibility of the the PTCDI-C8 were obtained. Finally,we discussed these parameters for optoelectronic applications andcompared with related parameters in literature.

Structural, Optical and Electrical Properties of PVA/PEO/SnO2 New Nanocomposites for Flexible Devices

Aseel Hadi,Ahmed Hashim,Yahya Al-Khafaji 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.3

Fabrication of polyvinyl alcohol (PVA)–polyethylene oxide (PEO) blend doped with tin dioxide (SnO 2 ) nanocomposites has been investigated for flexible electrical and optical applications. The prepared nanocomposites have low cost, lightweight, flexible, high corrosion resistance, good optical and electrical properties. These properties of fabricated nanocomposites make it useful for diff erent optoelectronics applications such as: sensors, solar cells, transistors, diodes, capacitors, energy storage etc. The structural, optical and electrical properties of (PVA–PEO–SnO 2 ) nanocomposites have been studied. The experimental results of optical properties for (PVA–PEO–SnO2) nanocomposites showed that the nanocomposites have higher absorbance in UV region at wavelength range (200–280) nm. This behavior makes the nanocomposites may be used for optoelectronics applications. The absorbance, absorption coeffi cient, extinction coeffi cient, refractive index, real and imaginary dielectric constants and optical conductivity of polymer blend are increased with the increase in SnO2 nanoparticles concentrations while the transmittance and energy band gap are decreased with the increase in SnO2 nanoparticles concentrations. The decrease in energy band gap is useful for diff erent optoelectronics devices industries. Also, the results showed that the dielectric constant and dielectric loss decrease while the conductivity increases with the increase in frequency. The dielectric constant, dielectric loss and conductivity are increased with the increase in SnO2 nanoparticles concentrations. The electrical properties showed that the (PVA–PEO–SnO2) nanocomposites have good dielectric parameters which it may be used for different electronics applications.

Modifying optical properties of phosphor-in-glass by varying phosphor size and content

Yie, Hoyong,Kim, Sunil,Kim, Yurian,Kim, Hyungsun North-Holland 2017 Journal of non-crystalline solids Vol.463 No.-

<P><B>Abstract</B></P> <P>Phosphor-in-glass (PIG) has been attracting attention as a stable encapsulant for light-emitting diodes. However, the influence of the phosphor size and content on the morphology and optical properties of PIG must be further studied to achieve the desired color properties by understanding the relationship between the phosphor mixing conditions and the morphology. In this study, two different sizes of YAG:Ce<SUP>3+</SUP> phosphors were used in different ratios and total amounts. The optical properties of the PIG samples were measured using an integrating sphere and UV-spectrometer, and cross-sectional scanning electron microscopy images were used to analyze the pore properties. The optical properties of PIG showed linear trends as functions of the pore and phosphor distributions, both of which affect the passage of light. This research shows that the desired color properties can be achieved in PIG by considering the phosphor mixing conditions and the related variations in the morphology.</P>

광학적 특성과 결합 특성 연구를 통한 CdO-P2O5계 유리의 구조-물성간 상관관계에 대한 추가적인 검증

정재엽 ( Jae Yeop Jung ),김영석 ( Young Seok Kim ),김종환 ( Jong Hwan Kim ),최수연 ( Su Yeon Choi ),김일구 ( Il Gu Kim ),박현준 ( Hyun Joon Park ),류봉기 ( Bong Ki Ryu ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.3

In this study, we re-verify the relationship between the structure and properties of cadmium phosphate glasses through the study of the optical and binding properties. We prepared cadmium phosphate glasses with various compositions, given by xCdO-(100-x)P2O5 (x=10-55 mol%), and analyzed their Fourier transform infrared spectra, X-ray photoelectron spectroscopy, optical band gap and other properties such as dissolution rate, thermal expansion coefficient, glass transition temperature, glass softening temperature. We found that the optical band gap and glass transition temperature decreased and thermal expansion coefficient increased with increasing CdO content. These results suggest that CdO acts as a network modifier in binary phosphate glass and weakens its structure. Futher, we found that the chemical durability and optical band gap is rapidly changed when the CdO content is more than 40 mol%. From these results, we can deduce that ionic bonding increases and covalent bonding decreases when the CdO content is more than 40 mol%.(Received Mary 16, 2014)

아크릴계 단량체 2-HEA와 EGPA의 조성에 따른 고분자 분산형 액정(PDLC)의 전기광학적 특성 평가

최종선 ( Jongseon Choi ),김영대 ( Young Dae Kim ),김소연 ( So Yeon Kim ) 한국공업화학회 2019 공업화학 Vol.30 No.2

지난 수십 년 동안 고분자 분산형 액정(polymer dispersed liquid crystal, PDLC)은 전기광학적으로 전환이 가능한 특성으로 인해 빛의 투과도를 자유롭게 조절할 수 있는 smart window를 개발하는 물질로서 주목을 받아왔다. 본 연구에서는 높은 구동전압과 낮은 명암비 등의 PDLC 문제점을 해결하기 위해 아크릴계 단량체 2-hydroxyethyl acrylate (2-HEA)와 ethylene glycol phenyl ether acrylate (EGPA)의 조성이 PDLC의 전기광학 특성에 미치는 영향을 평가하였다. 상온에서 10 cps 이하의 낮은 점도를 나타내는 2-HEA와 EGPA 단량체를 사용하여 제조하는 경우 보다 쉽게 capillary action에 의해서 indium tin oxide (ITO) glass 사이에 주입하는 공정이 가능하였다. Phenyl group를 포함한 EGPA 단량체가 대부분으로 이루어진 1 : 9인 단량체 혼합물로 만들어진 PDLC cell의 경우 전기장을 인가하지 않은 경우에도 불투명한 상태가 관측되지 않았고 인가 전압에 따라 매우 불안정한 투과율을 나타내었다. Cell gap thickness가 증가함에 따라 문턱전압(threshold voltage, V_th)과 포화전압(saturation voltage, V_sat)도 증가하는 경향을 나타내었으며, 20 μm의 cell gap thickness를 갖는 PDLC cell이 10과 40 μm의 경우 보다 상대적으로 높은 명암비를 나타내었다. 특히, 7 : 3 비율의 2-HEA : EGPA 단량체 혼합물을 사용하여 제조된 PDLC cell의 경우가 낮은 구동전압과 높은 명암비의 가장 우수한 전기광학적 특성을 나타내었다. Over the past several decades, the polymer dispersed liquid crystal (PDLC) has received particular attention as a material for developing smart window due to their electro-optical switchable properties. In this study, PDLC cells were fabricated using acrylate monomers, namely 2-hydroxyethyl acrylate (2-HEA) and ethylene glycol phenyl ether acrylate (EGPA), and the effect of the monomer composition on their electro-optical properties was investigated. The monomer mixture with a low viscosity (~10 cps) was easily filled between indium tin oxide (ITO) glasses by capillary action at room temperature. PDLC cells prepared using the mixture ratio of 1 : 9 (2-HEA : EGPA) did not show a complete opaque state at a 0 V condition but exhibited unstable electro-optical properties under an electric field. As the LC composition increased in the reaction mixture for PDLC cell preparation, the V_th (threshold voltage) and V_sat (saturation voltage) values as well as contrast ratio (CR) increased. V_th and V_sat values also increased with the cell gap thickness. PDLC cells with a 20 μm cell gap thickness exhibited higher CR than those with 10 and 40 μm cell gap thicknesses. Particularly, PDLC cells prepared using the mixture ratio of 7 : 3 (2-HEA : EGPA) showed excellent electro-optical properties such as a low driving voltage and high contrast ratio.

Real Time Optical-electrical Characterization of PbTe Thin Film Material for Super-resolution Optical Memory

( Hyun Seok Lee ),( Taek Sung Lee ),( Jeung Hyun Jeong ),( Su Youn Lee ),( Won Mok Kim ),( Byung Ki Cheong ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 ELECTRONIC MATERIALS LETTERS Vol.3 No.1

An experimental study was conducted in an effort to elucidate the origin of the nonlinear optical Properties of PbTe thin film, which previously had been demonstrated to be potentially usable for super-resolution optical memory. Using PbTe thin film device designed expressly for the experiment, transient optical transmittance and reflectance were measured together with the electrical voltage across the PbTe during pulsed irradiation with a 658nm laser of varying power. From the measured data, the absorption coefficient was derived as well as the carrier concentration as a function of laser power, demonstrating vividly that a decrease in the absorption coefficient with increasing laser power is directly related to the increase in photo-generated carriers. The observed correlation underlying the nonlinear optical properties of PbTe may be understood in light of saturable absorption resulting from band filling by carriers photo-generated under thermal influence and is a major cause of the material`s super-resolution effect.

Optical and Magneto-optical Properties of Fe-Mn Alloy Films

이주열,이영백,K. W. Kim,Y. V. Kudryavtsev 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

The electronic structures of α-Fe (bcc structure) and γ-FeMn (L10 structure) were calculated by using the all-electron full-potential linearized-augmented-plane-wave method within the generalized-gradient approximation. Both diagonal and off-diagonal components of the optical-conductivity (OC) tensor were calculated from the calculated electronic structures. The calculated OC spectra, both diagonal and off-diagonal, are compared with the experimental spectra of pure Fe, Mn-diluted (2.5 at.% of Mn concentration) Fe alloy film, and near-equiatomic FexMn1-x alloy films with x = 0.642 and 0.409. By applying the so-called λ-fitting, which simulates the effects of the real part of self-energy, the calculated OC spectra can successfully reproduce the experimental ones.

Properties of nano-ZnO/poly(vinyl alcohol)/poly(ethylene oxide) composite thin films

J. Lee,D. Bhattacharyya,A.J. Easteal,J.B. Metson 한국물리학회 2008 Current Applied Physics Vol.8 No.1

A series of poly(vinyl alcohol)/nano-ZnO composites were prepared by dispersing nano-ZnO in aqueous solutions containing mixtures of the biodegradable polymers poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), and composite thin films were prepared by casting. The introduction of nano-ZnO into PVA/PEO mixed solutions significantly decreased the resistivity of the solutions. Ultraviolet absorption, thermal behaviour and visco-elastic properties of the thin films were determined as a function of nano-ZnO content up to 15 wt%. Optimum film properties were obtained with 1 wt% nano-ZnO, higher proportions of nano-ZnO resulting in agglomeration of ZnO particles and deterioration in film properties. The Forouhi and Bloomer model was used for the modelling of ZnO thin films. A series of poly(vinyl alcohol)/nano-ZnO composites were prepared by dispersing nano-ZnO in aqueous solutions containing mixtures of the biodegradable polymers poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), and composite thin films were prepared by casting. The introduction of nano-ZnO into PVA/PEO mixed solutions significantly decreased the resistivity of the solutions. Ultraviolet absorption, thermal behaviour and visco-elastic properties of the thin films were determined as a function of nano-ZnO content up to 15 wt%. Optimum film properties were obtained with 1 wt% nano-ZnO, higher proportions of nano-ZnO resulting in agglomeration of ZnO particles and deterioration in film properties. The Forouhi and Bloomer model was used for the modelling of ZnO thin films.

논문 : 정보처리 및 복합기술 ; 광반사를 이용한 한국 논 토양 특성 추정

정선옥 ( S. O Chung ),정기열 ( K. Y. Jung ),( Kenneth A. Sudduth ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.1

An optical sensing approach based on diffuse reflectance has shown potential for rapid and reliable on-site estimation of soil properties. Important sensing ranges and the resulting regression models useful for soil property estimation have been reported. In this study, a similar approach was applied to investigate the potential of reflectance sensing in estimating soil properties for Korean paddy fields. Soil cores up to a 65-cm depth were collected from 42 paddy fields representing 14 distinct soil series that account for 74% of the total Korean paddy field area. These were analyzed in the laboratory for several important physical and chemical properties. Using air-dried, sieved soil samples, reflectance data were obtained from 350 to 2500 nm on a 3 nm sampling interval with a laboratory spectrometer. Calibrations were developed using partial least squares (PLS) regression, and wavelength bands important for estimating the measured soil properties were identified. PLS regression provided good estimations of Mg (R2=0.80), Ca (R2=0.77), and total C (R2=0.92); fair estimations of pH, EC, P2O5, K, Na, sand, silt, and clay (R2 = 0.59 to 0.72); and poor estimation of total N. Many wavelengths selected for estimation of the soil properties were identical or similar for multiple soil properties. More important wavelengths were selected in the visible-short NIR range (350-1000 nm) and the long NIR range (1800-2500 nm) than in the intermediate NIR range (1000-1800 nm). These results will be useful for design and application of in-situ close range sensors for paddy field soil properties.