Tailoring a Molecule’s Optical Absorbance Using Surface Plasmonics

Â Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 â‰¤ x â‰¤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the systemâ€™s network.

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Optical Absorbance of Porous Silicon on n-type Si (111) Surfaces Fabricated by Electrochemical Anodization Method

Materials Today Proceedings ◽

10.1016/j.matpr.2019.03.193 ◽

2019 ◽

Vol 13 ◽

pp. 87-91

Author(s):

Mita Handayani ◽

Nur'aini Dian Pratiwi ◽

Risa Suryana

Keyword(s):

Porous Silicon ◽

Electrochemical Anodization ◽

Optical Absorbance ◽

Anodization Method

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Black TiOx Films with Photothermal-Assisted Photocatalytic Activity Prepared by Reactive Sputtering

Materials ◽

10.3390/ma14102508 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2508

Author(s):

Quan Mao ◽

Meng Liu ◽

Yajie Li ◽

Yuquan Wei ◽

Yong Yang ◽

...

Keyword(s):

Photocatalytic Activity ◽

Magnetron Sputtering ◽

High Light ◽

Chemical Compositions ◽

Practical Application ◽

Dc Magnetron Sputtering ◽

Optical Absorbance ◽

Low Efficiency ◽

Tio2 Phase ◽

Photocatalytic Tio2

Titanium oxide is widely applied as a photocatalyst. However, its low efficiency and narrow light absorption range are two main disadvantages that severely impede its practical application. In this work, black TiOx films with different chemical compositions were fabricated by tuning target voltage and controlling O2 flow during reactive DC magnetron sputtering. The optimized TiOx films with mixed phases (TiO, Ti2O3, Ti3O5, and TiO2) exhibited fantastic photothermal and photocatalytic activity by combining high light-absorptive Ti2O3 and Ti3O5 phases with the photocatalytic TiO2 phase. The sample prepared with oxygen flow at 5.6 ± 0.2 sccm and target voltage near 400 V exhibited excellent optical absorbance of 89.29% under visible light, which could improve surface temperature to 114 °C under sunlight. This film could degrade Rhodamine-B up to 74% after 150 min of UV irradiation. In a word, this work provides a guideline for fabricating black TiOx films with photothermal-assisted photocatalytic activity by reactive DC magnetron sputtering, which could avoid the usage of hydrogen and is convenient for quantity preparation.

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An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions

Sensors ◽

10.3390/s21041099 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1099

Author(s):

Sheng-Chun Hung ◽

Chih-Cheng Lu ◽

Yu-Ting Wu

Keyword(s):

Aqueous Solutions ◽

Metal Ions ◽

Copper Ions ◽

Incident Light ◽

Copper Ion ◽

Intensity Change ◽

Optical Absorbance ◽

Sensing System ◽

Optic Sensor ◽

Cu Ions

The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.

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Multipod ZnO Nanoforms: Low Temperature Synthesis and Characterization

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.124 ◽

2007 ◽

Vol 7 (2) ◽

pp. 689-695 ◽

Cited By ~ 5

Author(s):

Tandra Ghoshal ◽

Soumitra Kar ◽

Subhajit Biswas ◽

Gautam Majumdar ◽

Subhadra Chaudhuri

Keyword(s):

Low Temperature ◽

Field Emission ◽

Cross Section ◽

Thermal Evaporation ◽

Synthesis And Characterization ◽

Low Temperature Synthesis ◽

Temperature Synthesis ◽

Optical Absorbance ◽

Higher Temperature ◽

Emission Studies

ZnO nanotetrapods were synthesized by a simple thermal evaporation of Zn powder at a relatively low temperature ∼600 °C. The tetrapods have four legs with hexagonal cross-section. Interpenetrating growth was observed in some of these nanotetrapods. Multipod ZnO nanoforms were produced at higher temperature. The optical characterizations such as optical absorbance, photoluminescence and Raman spectroscopy reveal excellent crystal qualities of these nanoforms. The field emission studies indicated that these nanoforms could be utilized in field emission based devices.

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Utilising polyphenylene oxide for high exposure solar UVA dosimetry

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-2759-2008 ◽

2008 ◽

Vol 8 (10) ◽

pp. 2759-2762 ◽

Cited By ~ 7

Author(s):

D. J. Turnbull ◽

P. W. Schouten

Keyword(s):

Thin Film ◽

Solar Spectrum ◽

Combined System ◽

High Exposure ◽

Optical Absorbance ◽

Preliminary Results ◽

Polyphenylene Oxide ◽

Film Form ◽

Uncertainty Level ◽

Uva Radiation

Abstract. A personal UV dosimeter that can quantitatively assess high exposure solar UVA exposures has been developed. The chemical polyphenylene oxide has been previously reported on its ability to measure high UVB exposures. This current research has found that polyphenylene oxide, cast in thin film form, is responsive to both the UVA and UVB parts of the solar spectrum. Further to this, the UVB wavelengths were filtered out with the use of mylar. This combined system responded to the UVA wavelengths only and underwent a change in optical absorbance as a result of UVA exposure. Preliminary results indicate that this UVA dosimeter saturates steadily when exposed to sunlight and can measure exposures of more than 20 MJ/m2 of solar UVA radiation with an uncertainty level of no more than ±5%.

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PREPARATION AND CHARACTERIZATION OF ORGANIC THIN FILM OF STEARIC ACID/PYRAZOLINE NANOPARTICLES

International Journal of Nanoscience ◽

10.1142/s0219581x06004243 ◽

2006 ◽

Vol 05 (02n03) ◽

pp. 199-205

Author(s):

YOUNG SOO KANG ◽

SUN WHA OH ◽

JONG HWA SUH

Keyword(s):

Stearic Acid ◽

Organic Thin Films ◽

Solid Substrate ◽

Organic Thin Film ◽

Blodgett Film ◽

Optical Absorbance ◽

Langmuir Blodgett ◽

Pressure Area

The organic thin films of stearic acid/pyrazoline nanoparticles were prepared by transferring Langmuir monolayer of stearic acid/pyrazoline nanoparticle onto the solid substrate. The complex of stearic acid/pyrazoline nanoparticle was studied with pressure–area isotherm at the air/water interface and identified with linearly increasing optical absorbance around 370 nm by increasing the number of deposited layers. The in situ domain structure and molecular orientation of the complex were measured with BAM. The surface morphology of the Langmuir–Blodgett film was observed with AFM. The dispersion of pyrazoline nanoparticle in the film was studied with TEM.

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Annealing-Induced Modifications in Physicochemical and Optoelectronic Properties of Ag-Doped Nanostructured CdS Thin Films

International Journal of Photoenergy ◽

10.1155/2012/264027 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Vidya S. Taur ◽

Rajesh A. Joshi ◽

Ramphal Sharma

Keyword(s):

Thin Films ◽

Annealing Treatment ◽

Cost Effective ◽

Peak Position ◽

Optoelectronic Properties ◽

Sem Images ◽

X Ray ◽

Optical Absorbance ◽

Air Atmosphere ◽

Cds Thin Films

The Ag-doped nanostructured CdS thin films are grown by simple, cost effective chemical ion exchange technique at room temperature on ITO-coated glass substrate. These as grown thin films are annealed at 100, 200, 300, and 400°C in air atmosphere for 1 hour. To study the effect of annealing on physicochemical and optoelectronic properties, these as grown and annealed thin films are characterized for structural, compositional, morphological, optical, and electrical properties. X-ray diffraction (XRD) pattern reveals polycrystalline nature of these thin films with increase in crystallite size from 6.4 to 11.2 nm, from XRD the direct identification of Ag doping in CdS thin films cannot be judged, while shift in characteristics peak position of CdS is observed. The Raman spectrum represents increase in full width at half maxima and intensity of characteristic peak, confirming the material modification upon annealing treatment. Presence of Cd, Ag, and S in energy dispersive X-ray analysis spectra (EDAX) confirms expected elemental composition in thin films. Scanning electron microscopy (SEM) images represent grain growth and agglomeration upon annealing. Red shift in optical absorbance strength and energy band gap values from 2.28 to 2.14 eV is obtained.I-Vresponse obtained from as grown and annealed thin films shows an enhancement in photosensitivity from 72% to 96% upon illumination to 100 mW/cm2light source.

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