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The Signatures of Acid Concentration on the optical band gap and Associated band Tails of Chitosan from Shrimp for Application in Optoelectronic Devices

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Advances in Chemical Engineering and Science 2022年第1期12卷 1-12页

作者： Edwin Atego John O. Agumba Godfrey O. Barasa Department of Physical Sciences Jaramogi Oginga Odinga University of Science and Technology (JOOUST) Bondo Kenya

Over the recent years, the global increase of electronic wastes from electrical and electronic devices (e-wastes) has been on an alarming trend in quantity and toxicity and e-wastes are non-biodegradable resulting in its cumulative increase over time. Changes in technology and unrestricted regional movement of electrical devices have facilitated the generation of more e-wastes leading to high levels of air, soil and water pollution. To address these challenges, biodegradable organic components such as chitosan have been used to replace their inorganic counterparts for optoelectronic device applications. However, in-depth knowledge on how such materials can be used to tune the optical properties of their hybrid semiconductors is unrivaled. Thus, systematic studies of the interplay between the preparation methods and optical band gap and Urbach energy of such organic components are vital. This study has thus been dedicated to map out the effect of acid concentrations during chitosan extraction on the corresponding optical band gap and Urbach energy with a view to improving its applications in optoelectronic devices. The, 1.0 to 2.5 molar hydrochloric acid (HCl) was used for 12 hours at room temperature during demineralization and 2.0 molar sodium hydroxide (NaOH) during deprotonation processes. The absorbance spectrum of the samples was collected by UV-Vis spectrophotometer and band gap energies were analyzed by performing Tauc’s plot. This study revealed that the energy band gap of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 3.72 eV, 3.50 eV, 3.45 eV and 3.36 eV respectively. Furthermore,

关键词： Chitosa optical band gap Urbach Energy Absorbance Spectrum Tauc Plot

Glass Formation and optical band gap Studies on Bi_2O_3-B_2O_3-BaO Ternary System

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Journal of Wuhan University of Technology(Materials Science) 2009年第5期24卷 716-720页

作者：陈飞飞戴世勋 College of Information Science and Engineering Ningbo University

The glass forming region of Bi2O3-B2O3-BaO ternary system was investigated. A serial of glass samples with high Bi2O3 content in Bi2O3-B2O3-BaO system were prepared by using conventional melting and quenching meld, and the refractive indexes and absorption spectra of samples were measured. It is found that the refractive index of samples as well as the UV absorption increase with the increase of BaO content. According to the Tauc law, optical band gap Eopg which is assumed to be the effective energy band gap Eg is calculated and decreases with the increasing BaO content, and the ratio of Eg/Eopg is 1.3.

关键词： glass formation bismuth glass refractive index optical band gap

The effect of Zn incorporation on the optical band gap of CuGaS2:Ti thin films

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The effect of Zn incorporation on the optical band gap of Cu...

Structural,optical,electrical,and dielectric relaxation properties of rare earth containing sodium bismuth titanate Na_(0.5)Bi_(0.5)TiO_(3) perovskite:Effect of ionic radius

第四届新型太阳能电池学术研讨会

作者： Qingyan Li Yanlai Wang Ying Yang Chong Deng Xiangdong Cao Inner Mongolia University

A novel intermediate band(IB) material of Zn incorporation in Ti-doped CuGaS thin films has been successfully fabricated via a facile non vacuum method including ball milling, spin-coating and *** results have shown that the IB position of Ti-doped CuGaS thin films can be adjusted by Zn *** a given Ti%, raising Zn concentration leads to a significantly enhanced light absorption, which can be directly observed in the UV-Vis-NIR absorption *** this study, the optical band gap has a shortening of 0.19 eV when 0.6 % Zn is added to the 1.5 % Ti-doped *** to the Zn addition, the grains grow larger and squeeze together, which is observable from the surface morphology of the thin films using scanning electron microscope(SEM).The energy dispersive X-ray analysis(EDAX) spectrum demonstrates that ball milling can effectively make Ti and Zn elements co-coped evenly into CuGaS thin ***, the improved optical property of the Ti-doped CuGaS thin films due to the Zn incorporation also sheds lights in developing new material that could be a potential light absorption layers candidate of high efficiency solar cells.

关键词： Intermediate band CuGa1-x-yTixZnyS2 thin films optical band gap chalcopyrite

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Journal of Rare Earths 2024年第2期42卷 383-391,I0006页

作者： Rajdip Roy Abhigyan Dutta Department of Physics The University of BurdwanBurdwan713104India

The main focus of this work is to study the effect of the ionic radius of different rare earth dopant cations RE^(3+)(RE=La,Sm,Dy,and Ho) on structural and various physical properties of sodium bismuth titanate(Na_(0.5)B_(0.5)TiO_(3),NBT) based perovskite *** X-ray diffraction data indicate the successful formation of the rhombohedral phase(space group R3c) of NBT nano perovskite incorporated with various rare earth ions in *** lattice parameters were found to increase linearly with the ionic radius of the dopant *** ionic radii and atomic mass of rare earth dopants appear to be essential factors in the grain growth of the prepared *** grain growth results in better crystallinity of the sample by reducing the microstrain with the increase of dopant ionic *** emission scanning electron microscopy and energy-dispersive X-ray spectra confirm the prepared compositions' phase purity and *** UV-Vis spectra reveal that La-doped NBT composition exhibits the lowest optical band gap,which unfolds the application of NBT-based perovskite as photoactive *** ac conductivity and complex impedance spectra unveil that the composition with the largest ionic radius,i.e.,La-doped NBT compound,exhibits the highest dc and bulk conductivity with the lowest activation *** frequency-dependent dielectric data follows Havriliak-Negami(HN) formalism and non-Debye type relaxation *** also indicate that La-doped NBT composition exhibits the highest dielectric strength ***,this study first elaborates that the increasing ionic radius of the rare earth dopant cation in the Bi-site of NBT perovskite improves its microstructural,optical,and electrical properties.

关键词： Rare earth doped NBT Microstructural analysis optical band gap AC Conductivity Dielectric relaxation Rare earths

Dual-phase coexistence enables to alleviate resistance drift in phase-change films

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Journal of Semiconductors 2024年第7期45卷 55-59页

作者： Tong Wu Chen Chen Jinyi Zhu Guoxiang Wang Shixun Dai Laboratory of Infrared Materials and Devices The Research Institute of Advanced TechnologiesNingbo UniversityNingbo 315211China Institute of Ocean Engineering Ningbo UniversityNingbo 315211China

The amorphous phase-change materials with spontaneous structural relaxation leads to the resistance drift with the time for phase-change neuron synaptic devices. Here, we modify the phase change properties of the conventional Ge_2Sb_2Te_5(GST) material by introducing an SnS phase. It is found that the resistance drift coefficient of SnS-doped GST was decreased from 0.06 to 0.01. It can be proposed that the origin originates from the precipitation of GST nanocrystals accompanied by the precipitation of SnS crystals compared to single-phase GST compound systems. We also found that the decrease in resistance drift can be attributed to the narrowed bandgap from 0.65 to 0.43 eV after SnS-doping. Thus, this study reveals the quantitative relationship between the resistance drift and the band gap and proposes a new idea for alleviating the resistance drift by composition optimization, which is of great significance for finding a promising phase change material.

关键词： phase change films X-ray methods resistance drift optical band gap

Study of Structural, optical, Electrical and Dielectric Properties of Gd-Doped ZnO Composites Synthesized by Solid State Reaction Method

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Open Journal of Composite Materials 2024年第2期14卷 91-108页

作者： Santosh Kumar Kundara Kanhaiya Chawla Dinesh Kumar Yadav Chhagan Lal Balram Tripathi Narendra Jakhar Department of Physics University of Rajasthan Jaipur India Sw. P.N.K.S. Government PG College Dausa India Government PG College Pratapgarh India S.S. Jain Subodh PG (Autonomous) College Jaipur India

In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn1−xGdxO, x = 0, 0.05, 0.10) prepared by solid-state reaction method. XRD spectra confirm the wurtzite hexagonal phase with a grain size distribution of 42 - 47 nm. The FT-IR spectra confirm bonding behavior like Zn-O, O=C=O, and O-H stretching modes. FESEM micrographs show that the grains of crystallites possess nearly spherical morphology. optical absorption spectra confirm that the optical band gap decreases systematically from 3.19 eV to 3.15 eV for x = 0.0 to x = 0.10 samples. For all samples, PL spectra exhibited near-band emission, blue emission, and green emission peaks. The dielectric constant decreases as the applied frequency increases. Hall effect results show that with increasing doping concentration of Gd, mobility and resistivity increase while bulk concentration decreases. Current-Voltage study shows that current increases when temperature is increased. Rare earth-doped ZnO is potential material used for optoelectronics and spintronics device applications. Properties of Gd-doped ZnO are studied by various research groups, but dielectric studies are limitedly reported. Therefore, the present research work aims to study the change of electrical, optical, and dielectric properties of Gd-doped ZnO for device applications.

关键词： ZnO:Gd Composites optical band gap Green Emission Dielectric Constant

Texture coefficient and band gap tailoring of Fe-doped SnO_(2) nanoparticles via thermal spray pyrolysis

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Rare Metals 2022年第4期41卷 1332-1341页

作者： Majibul Haque Babu Bidhan Chandra Dev Jiban Podder Department of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) *** surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe *** EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content *** studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping *** grain size is found to decrease with the increase in Fe *** studies also specify that the films have tetragonal rutile-type structure with mixed secondary *** texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping *** resistivity and the optical absorbance are found to increase with Fe *** direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.

关键词： SnO_(2)thin film Thermal spray pyrolysis Texture coefficient optical band gap

Influence of Cu doping in Magnesium Hydroxide Nanoparticles for bandgap Engineering

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Journal of Wuhan University of Technology(Materials Science) 2023年第3期38卷 485-489页

作者： SYED Masood Raza S NASEEM Shah ADEEL Tahir YASMEEN Bibi Department of Physics Federal Urdu University of ArtsScience&TechnologyKarachiPakistan Department of Chemistry Federal Urdu University of ArtsScience&TechnologyKarachiPakistan

Cu doped Mg(OH)_(2) nanoparticles were synthesized with varying concentrations from 0 to 10%by a chemical synthesis technique of coprecipitation.X-rays diffraction (XRD) of the samples confirms that all the samples acquire the hexagonal crystal *** results indicated the solubility limit of dopant in the host material and the secondary phase of CuO was observed beyond 3%Cu doping in Mg(OH)_(2).The reduction in the size of nanoparticles was observed from 166 to 103 nm for Mg(OH)_(2) and 10% Cu doped Mg(OH)_(2)samples,*** shift in absorption spectra exhibited the systematical enhancement in optical bandgap from 5.25 to 6.085 eV.A good correlation was observed between the bandgap energy and crystallite size of the nanocrystals which confirmed the size induced effect in the *** transformation in the sample morphology was observed from irregular spherical particles to sepals like shapes with increasing the Cu concentration in the host *** energy dispersive X-Ray (EDX) analysis confirmed the purity of mass percentage composition of the elements present in the samples.

关键词： Cu doped Mg(OH)_(2) nanoparticles phase purity optical band gap morphologies

Complex coordinated functional groups: A great genes for nonlinear optical materials

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Chinese Chemical Letters 2022年第5期33卷 2301-2315页

作者： Weikang Wang Dajiang Mei Shaoguo Wen Jian Wang Yuandong Wu College of Chemistry and Chemical Engineering Shanghai University of Engineering ScienceShanghai 201620China Department of Chemistry and Biochemistry Wichita State UniversityWichitaKS 67260United States State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Complex coordinated functional groups[MA_(x)B_(y)](M=Central coordination element;A,B=P,O,S,Se,F,Cl,Br or I)are composed of different types of anions A,B jointly linked to the same central cation M,which are in high potential to tune the physical properties of materials,e.g.,second-order susceptibility,energy gaps and ***,Compound containing complex coordinated functional groups have attracted great attention in the nonlinear optical(NLO)field and a large number of this type crystals exhibit promising NLO ***,the inherent relationship between ionic group structure and optical properties of complex coordinated NLO materials have not been systematically *** article systematically summarizes complex coordinated NLO materials in recent five years from the perspective of the internal relationship between crystal structure and optical *** addition,we propose the ideal combination and arrangement modes for structural building units,and also reveal the influence of complex coordinated functional groups[MA_(x)B_(y)]toward the NLO response,optical band gap and phase matching ability of complex coordinated NLO materials.

关键词： Complex coordinated Nonlinear optical Second harmonic generation optical band gap Structure-performance relationship