Growth mechanism and optical characteristics of Nd:YAG laser ablated amorphous cinnamon nanoparticles produced in ethanol: Influence of accumulative pulse irradiation time variation

2021 ◽  
Vol 43 ◽  
pp. 100889
Author(s):  
A.A. Salim ◽  
S.K. Ghoshal ◽  
H. Bakhtiar
Keyword(s):  
Growth Mechanism ◽  
Time Variation ◽  
Nd:Yag Laser ◽  
Irradiation Time ◽  
Optical Characteristics ◽  
Pulse Irradiation

Optical Characteristics of Multilayer Reduced Graphene Oxides Films Fabricated Using UV Oven Spraying Technique with Various Interval Irradiation Time

2021 ◽  
Vol 1028 ◽  
pp. 279-284
Author(s):  
Nur Khanifah ◽  
Diyan Unmu Dzujah ◽  
Vika Marcelina ◽  
Rahmat Hidayat ◽  
Fitrilawati ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Irradiation Time ◽  
Active Material ◽  
Reduction Process ◽  
Optical Characteristics ◽  
Graphene Oxides ◽  
Super Capacitor ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Coating Method

Reduced graphene oxide (RGO) is promising candidate to be used as an active material of super capacitor electrodes. Graphene oxide (GO) is mostly used as a precursor, therefore it is needed to remove its oxygen containing functional groups. Generally, the RGO films are obtained from Graphene Oxide (GO) films which are then treated using thermal reduction or photo reduction process. We developed a spraying coating method that called as UV oven spraying by combining spraying coating method and photo reduction process. By this deposition method, we can obtain RGO films directly from the GO precursor since deposition and photo reduction steps are taken place at the same time. Level of oxygen removal of the obtained RGO film depends on irradiation intensity and length of irradiation. In this work, we report the effect of varied length of irradiation time on the RGO optical characteristics. We prepared multilayer of RGO films using UV oven spraying technique on quartz substrates from 0.5 mg/ml commercial GO dispersion (Graphenea) with varied the UV irradiation time. We used 125-Watt mercury lamp that was set at distance of 30 cm from substrates. We examined the effect of varied of length of irradiation time on its optical characteristics using UV-Vis Spectroscopy. Level of reduction by provided irradiation time was examined using SEM/EDS measurement.

scholarly journals SINTESIS FOTOKATALIS NANOPARTIKEL ZnO UNTUK MENDEGRADASI ZAT WARNA METHYLENE BLUE

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Tirza C. Raganata ◽  
Henry Aritonang ◽  
Edi Suryanto
Keyword(s):  
Methylene Blue ◽  
Exposure Time ◽  
Zno Nanoparticles ◽  
Time Variation ◽  
Contact Time ◽  
Irradiation Time ◽  
Coprecipitation Method

ABSTRAKTelah dilakukan penelitian tentang fotokatalis metilen biru menggunakan nanopartikel ZnO yang disentisis dengan metode kopresipitasi. Kemampuan fotokatalis dilakukan terhadap zat warna methylene blue 5 ppm menggunakan fotokatalis ZnO yang disinari sinar UV-A selama 30, 60, 120, 150, dan 180 menit. Penentuan konsentrasi dihitung berdasarkan absorbansi yang didapatkan dari hasil Spektrofotometri UV-Vis dan dalam rumus menghitung % degradasi. Hasil penelitian menunjukkan bahwa yang memiliki kemampuan fotokatalis paling baik adalah Nanopartikel ZnO 10% yaitu dengan nilai persen degradasi untuk variasi waktu penyinaran 30 menit adalah sebesar 51,82%, 60 menit sebesar 65,26%, 120 menit sebesar 71,25%, 150 menit sebesar 75,78%, dan 180 menit sebesar 71,01%. Dan waktu penyinaran optimum terjadi pada waktu kontak 150 menit. ABSTRACTA research on photocatalysts of methylene blue using ZnO nanoparticles were analyzed using coprecipitation method. The ability of photocatalysts was carried out on 5 ppm methylene blue dyes using ZnO photocatalysts which were exposed to UV-A rays for 30, 60, 120, 150, and 180 minutes. Determination of concentration was calculated based on the absorbance obtained from the results of the UV-Vis Spectrophotometry test reading and in the formula to calculate% degradation. The results showed that the best photocatalysts ability was ZnO 10% nanoparticles, ie the percent degradation value for 30 minutes irradiation time variation was 51.82%, 60 minutes was 65.26%, 120 minutes was 71.25%, 150 minutes at 75.78%, and 180 minutes at 71.01%. And the optimum exposure time occurs at 150 minutes contact time. 

scholarly journals Optical characteristics of type-II hexagonal shaped GaSb Quantum dots on GaAs synthesized using nanowire self-growth mechanism from Ga metal droplet

2021 ◽  
Author(s):  
Min Baik ◽  
Ji-hoon Kyhm ◽  
Hang-Kyu Kang ◽  
Kwang-Sik Jeong ◽  
Jong Su Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Microscope ◽  
Growth Mechanism ◽  
Gaas Layer ◽  
Band Alignment ◽  
Optical Characteristics ◽  
Droplet Epitaxy ◽  
Type Ii ◽  
Temperature Dependent ◽  
Bulk Gaas

Abstract We report the growth mechanism and optical characteristics of type-II band-aligned GaSb quantum dots (QDs) grown on GaAs using droplet epitaxy-driven nanowire formation mechanism in with molecular beam epitaxy (MBE). Using transmission electron microscope (TEM) and scanning electron microscope (SEM) images, we confirmed that the QDs, which comprise zinc-blende crystal structures with hexagonal shape, were successfully grown through the formation of a nanowire from a Ga droplet with less strain between GaAs and GaSb. Photoluminescence (PL) peaks of GaSb, which are capped by the GaAs layer, are observed at 1.11 eV, 1.26 eV, and 1.47 eV, assigned to the QDs, a wetting-like layer (WLL), and bulk GaAs, respectively, at the measurement temperature of 14 K and excitation laser power of 30 mW. The integrated PL intensity of the QDs is significantly stronger than the WLL, which indicates well-grown GaSb QDs on GaAs and the generation of an interlayer exciton, as shown in the power and temperature-dependent PL, respectively. In addition, Time-resolved PL (TRPL) data show that the GaSb QD and GaAs layer form a self-aligned type-II band alignment, and temperature-dependent PL data exhibit a high equivalent internal quantum efficiency of 15+/-0.2%.

scholarly journals Screw-Dislocation-Driven Hierarchical Superstructures of Ag-Ag2O-AgO Nanoparticles

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1084
Author(s):  
Hua Yang ◽  
Jing Ru Zhang ◽  
Wentao Cao ◽  
Jin Zhen ◽  
Ji Hong Wu
Keyword(s):  
Screw Dislocation ◽  
Uv Irradiation ◽  
Growth Mechanism ◽  
Irradiation Time ◽  
Structural Evolution ◽  
Physiochemical Properties ◽  
Promising Strategy ◽  
Photochemical Method ◽  
Step Density ◽  
Average Size

Constructing multi-dimensional hierarchical superstructures has been, for a longtime, regarded as a promising strategy for modifying the physiochemical properties of nanomaterials. Guided by this rule, this work reports the synthesis of hierarchical superstructures of Ag-Ag2O-AgO nanoparticles (HSANs) using a convenient and surfactant-less photochemical method under 254 nm UV-irradiation. The formation of the HSANs superstructures is dominated by screw-dislocation-driven growth mechanism at low supersaturation condition. The structural evolution of the HSANs superstructures has been systematically investigated. The average size of the HSANs superstructures increased with prolonged 254 nm UV-irradiation. The step density on the superstructure surfaces also increased along with the 254 nm UV-irradiation time.

scholarly journals Influence of Irradiation Time on the Structural and Optical Characteristics of CuSe Nanoparticles Synthesized via Microwave-Assisted Technique

ACS Omega ◽  
2021 ◽  
Author(s):  
Ibrahim Garba Shitu ◽  
Josephine Ying Chyi Liew ◽  
Zainal Abidin Talib ◽  
Hussein Baqiah ◽  
Mohd Mustafa Awang Kechik ◽  
...  
Keyword(s):  
Irradiation Time ◽  
Optical Characteristics ◽  
Microwave Assisted

scholarly journals Optical characteristics of type-II hexagonal-shaped GaSb quantum dots on GaAs synthesized using nanowire self-growth mechanism from Ga metal droplet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Baik ◽  
Ji-hoon Kyhm ◽  
Hang-Kyu Kang ◽  
Kwang-Sik Jeong ◽  
Jong Su Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Growth Mechanism ◽  
Internal Quantum Efficiency ◽  
Band Alignment ◽  
Optical Characteristics ◽  
Droplet Epitaxy ◽  
Type Ii ◽  
Temperature Dependent ◽  
Bulk Gaas

AbstractWe report the growth mechanism and optical characteristics of type-II band-aligned GaSb quantum dots (QDs) grown on GaAs using a droplet epitaxy-driven nanowire formation mechanism with molecular beam epitaxy. Using transmission electron microscopy and scanning electron microscopy images, we confirmed that the QDs, which comprised zinc-blende crystal structures with hexagonal shapes, were successfully grown through the formation of a nanowire from a Ga droplet, with reduced strain between GaAs and GaSb. Photoluminescence (PL) peaks of GaSb capped by a GaAs layer were observed at 1.11 eV, 1.26 eV, and 1.47 eV, assigned to the QDs, a wetting-like layer (WLL), and bulk GaAs, respectively, at the measurement temperature of 14 K and excitation laser power of 30 mW. The integrated PL intensity of the QDs was significantly stronger than that of the WLL, which indicated well-grown GaSb QDs on GaAs and the generation of an interlayer exciton, as shown in the power- and temperature-dependent PL spectra, respectively. In addition, time-resolved PL data showed that the GaSb QD and GaAs layers formed a self-aligned type-II band alignment; the temperature-dependent PL data exhibited a high equivalent internal quantum efficiency of 15 ± 0.2%.

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