Effects of annealing temperature on photoluminescence of ZnO nanorods hydrothermally grown on a ZnO:Al seed layer
TL;DR: In this paper, the effects of annealing treatment on the optical and structural properties of ZnO nanorods were studied by photoluminescence (PL), transmittance, scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements.
About: This article is published in Optical Materials.The article was published on 2013-10-01. It has received 30 citations till now. The article focuses on the topics: Nanorod & Photoluminescence.
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TL;DR: In this paper, both pure and Al doped ZnO thin films were fabricated on glass substrates by sol-gel method, and it was found that all the thin films have a preferential c-axis orientation.
Abstract: Pure and Al doped ZnO thin films were fabricated on glass substrates by sol-gel method. It is found that all the thin films have a preferential c-axis orientation. With increase of Al doping, the peak position of the (002) plane is shifted to the low 2θ value. A minimum resistivity of 6.2×10~(-4) Ω·cm is obtained for the film doped with 1.5 % Al. However, the resistivity increases with increasing Al concentration. The bandgap is found to broaden with increasing dopant concentration, and it is found that doping with Al has the effect of shifting the optical absorption to the shorter wavelength, which both cases are attributed to the Burstein-Moss shift.
155 citations
TL;DR: Au doped ZnO (ZnO:Au) nanostructures were synthesized by ultrasound assisted wet chemical method as mentioned in this paper, which showed the formation of nanorods having wurtzite structure and c-axis orientation.
59 citations
TL;DR: In this article, three different precursors viz. zinc acetate, zinc sulfate, and zinc chloride were used for annealing of thin ZnO thin films.
43 citations
TL;DR: With the enhanced electron extraction induced by the ZnO/PFN bilayer structure and PTB7:ICBA:PC71BM ternary system, the corresponding inverted PSC device shows a high PCE of 9.3%, which is more than a 15% improvement compared to the ZNO- or PFN-only devices.
Abstract: A highly efficient inverted polymer solar cell (PSC) has been successfully demonstrated by using a ZnO nanoparticle (NP) and poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) bilayer structure as an effective electron collecting layer. This ZnO/PFN bilayer structure is designed to combine the advantages of both ZnO and PFN, based on the performance comparison of ZnO-only, PFN-only, and ZnO/PFN bilayer devices in our work. ZnO NPs can serve as an efficient electron transport and buffer layer for reduced series resistance, while the PFN interlayer can improve the energy level alignment of devices through the formation of an interfacial dipole. With the enhanced electron extraction induced by the ZnO/PFN bilayer structure and PTB7:ICBA:PC71BM ternary system, the corresponding inverted PSC device shows a high PCE of 9.3%, which is more than a 15% improvement compared to the ZnO- or PFN-only devices.
41 citations
TL;DR: In this paper, the photocatalytic performance of Mg-doped ZnO nanoparticles, synthesized through the polyacrylamide polymer method, was investigated by the photodegradation of the methylene blue (MB) solution.
Abstract: The photocatalytic performance of Mg-doped ZnO (MZO) nanoparticles, synthesized through the polyacrylamide polymer method, was investigated by the photodegradation of the methylene blue (MB) solution The nanoparticles were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, and UV–vis absorption spectrum The results demonstrate that the catalysts present different photodegradation performances with varying calcination temperatures of the as-synthesized Mg-doped ZnO precursor It is found that the highest photodegradation of the MB solution was achieved by the catalyst with a 47 nm particle size, which had the lowest oxygen vacancies The influence of operational parameters of pH and initial dye concentration was evaluated Catalyst activity remained at 95% of its initial value even after the photodegradation process was repeated for nine times Moreover, three intermediate products, possessing the OH, O2− and h+ groups were detected in the photodegradation processes Hence, we attribute the enhanced photocatalytic properties of the ZnO nanoparticles to the lower amount of oxygen vacancies, which are a consequence of Mg-doping preventing electron-hole recombination
35 citations
References
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01 Jan 1974
TL;DR: In this article, the nature of the amorphous state and the electronic properties of the Amorphous Semi-conductors have been investigated in the context of liquid semiconductors.
Abstract: 1 The Nature of the Amorphous State.- 2 Structure of Amorphous Semi-conductors.- 3 Electronic Structure of Disordered Materials.- 4 Optical Properties of Amorphous Semiconductors.- 5 Electronic Properties of Amorphous Semiconductors.- 6 Switching and Memory in Amorphous Semiconductors.- 7 Structure and Electronic Properties of Liquid Semiconductors.
4,636 citations
TL;DR: In this article, the authors explore the interrelationships between the green 510 nm emission, the free-carrier concentration, and the paramagnetic oxygen vacancy density in commercial ZnO phosphors by combining photoluminescence, optical absorption, and electron paramagnetic resonance spectroscopies.
Abstract: We explore the interrelationships between the green 510 nm emission, the free‐carrier concentration, and the paramagnetic oxygen‐vacancy density in commercial ZnO phosphors by combining photoluminescence, optical‐absorption, and electron‐paramagnetic‐resonance spectroscopies. We find that the green emission intensity is strongly influenced by free‐carrier depletion at the particle surface, particularly for small particles and/or low doping. Our data suggest that the singly ionized oxygen vacancy is responsible for the green emission in ZnO; this emission results from the recombination of a photogenerated hole with the singly ionized charge state of this defect.
3,487 citations
TL;DR: In this paper, photoluminescent, undoped ZnO films have been fabricated using spray pyrolysis of zinc nitrate solution using a polycrystalline hexagonal wurtzite type structure with no preferred orientation.
Abstract: Photoluminescent, undoped ZnO films have been fabricated using spray pyrolysis of zinc nitrate solution The luminescent films had a polycrystalline hexagonal wurtzite type structure with no preferred orientation Photoluminescence intensity was critically dependent on substrate temperature during spray pyrolysis and on post-annealing temperature Green, photoluminescent films possessed a porous structure while orange films possessed a close packed granular morphology Green luminescence appears to be due to oxygen vacancies in a layer just below the crystallite surface
1,006 citations
TL;DR: In this paper, a C-axis vertically aligned ZnO nanorod arrays were synthesized using a simple hydrothermal route, with a diameter of 30-100nm and a length of about several hundred nanometres.
Abstract: C-axis vertically aligned ZnO nanorod arrays were synthesized on a ZnO thin film through a simple hydrothermal route. The nanorods have a diameter of 30–100 nm and a length of about several hundred nanometres. The gas sensor fabricated from ZnO nanorod arrays showed a high sensitivity to H2 from room temperature to a maximum sensitivity at 250 °C and a detection limit of 20 ppm. In addition, the ZnO gas sensor also exhibited excellent responses to NH3 and CO exposure. Our results demonstrate that the hydrothermally grown vertically aligned ZnO nanorod arrays are very promising for the fabrication of cost effective and high performance gas sensors.
662 citations
TL;DR: In this article, the effect of oxygen-vacancy-related defects on gas-sensing properties of ZnO-nanowire gas sensors was investigated and it was shown that the sensitivity of the sensors to NO2 gas is linearly proportional to the photoluminescence intensity.
Abstract: The effect of oxygen-vacancy-related defects on gas-sensing properties of ZnO-nanowire gas sensors was investigated. Gas sensors were fabricated by growing ZnO nanowires bridging the gap between two prepatterned Au catalysts. The sensor displayed fast response and recovery behavior with a maximum sensitivity to NO2 gas at 225 °C. Gas sensitivity was found to be linearly proportional to the photoluminescence intensity of oxygen-vacancy-related defects in both as-fabricated and defect-controlled gas sensors by postannealing in Ar and H2 atmosphere. This result agrees well with previous theoretical prediction that oxygen vacancies play a role of preferential adsorption sites for NO2 molecules.
659 citations