Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.

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Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals.

Synthetic control over inorganic nanocrystals has made dramatic strides so that a great number of binary and a few ternary or more complex compounds can now be prepared with good control over size and physical properties. Recently, chemists have tackled the long-standing challenge of introducing dopant atoms into nanocrystals, and strategies that apply across diverse compositions are beginning to emerge. In this review, we first briefly summarize the array of characterization methods used to assess doping efficacy for reference throughout the discussion. We then enumerate chemical strategies for doping with illustrative examples from the literature. A key concept is that the reactions leading to growth of the host crystal and to deposition of dopant ions must be balanced to succeed in incorporating dopants during crystal growth. This challenge has been met through various chemical strategies, and new methods, such as postsynthetic diffusion of dopant ions, continue to be developed. The opportunity to deli...

Chemistry of Doped Colloidal Nanocrystals

Preparation of highly efficient Al-doped ZnO photocatalyst by combustion synthesis

Application of advanced materials in sonophotocatalytic processes for the remediation of environmental pollutants.

Recent developments of two-dimensional graphene-based composites in visible-light photocatalysis for eliminating persistent organic pollutants from wastewater

Fabrication of NiFe layered double hydroxide/reduced graphene oxide (NiFe-LDH/rGO) nanocomposite with enhanced sonophotocatalytic activity for the degradation of moxifloxacin

SiO2-TiO2 thin films for use as fiber optic guiding layers of optical DNA biosensors were fabricated by the sol-gel dip coating technique. The chemical structure and the surface morphology of the films were characterized before immobilization. Single probe DNA strands were immobilized on the surface and the porosity of the films before the hybridization process was measured. Refractive index values of the films were measured using a Metricon 2010 prism coupler. On the surface of each film, 12 different spots were taken for measurement and calculation of the mean refractive index values with their standard deviations. The increased refractive index values after the immobilization of single DNA strands indicated that immobilization was successfully achieved. A further refractive index increase after the hybridization with target single DNA strands showed the possibility of detection of the E. coli O157:H7 EDL933 species using strands of 20-mers (5′-TAATATCGGTTGCGGAGGTG -3′) sequence.

https://www.mdpi.com/1424-8220/9/6/4890/pdf

A Novel Label-Free Optical Biosensor Using Synthetic Oligonucleotides from E. coli O157:H7: Elementary Sensitivity Tests

ZnO:Al ceramics (Zn:Al, 0.95:0.05) were prepared by using sol-gel derived nanocrystalline powders. XRD patterns of the doped ceramics revealed the existence of both zincite (JCPDS 36-1451) and gahnite (JCPDS 5-0669) phases. Gahnite phase (ZnAl2O4) was segregated along the ZnO grain boundaries. At the sintering temperature of 1200 °C, relative density of the undoped and Al doped ceramics were measured as 0.695 and 0.628, respectively. Both grain size and relative density of the ceramics decreased with Al doping. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Sintering behavior of ZnO:Al ceramics fabricated by sol‐gel derived nanocrystalline powders

Hydroxyapatite (HA) and HA/bioactive glass (49S) films were deposited on Si(100) substrates by a sol-gel dip-coating method. The microstructure and in vitro bioactivity of the films were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Polycrystalline HA and amorphous bioactive glass films were obtained after annealing at 600 and 400 °C, respectively. The crystallization temperature of HA was determined to be around 568 °C. The surfaces of the HA films were covered with an apatite layer consists of spherulites formed by nanosized needle-like aggregates after the soaking in simulated body fluid (SBF) for 10 days, while amorphous HA/bioactive glass surface was covered with larger spherical crystallites. Both XPS and EDS results obtained from HA/bioactive glass film, after soaking in SBF, showed increasing P amounts on the surface at the expense of Si. The higher density of the newly formed layer on HA/bioactive glass surface than that of the HA surface after 10 days of soaking was evidence of increased reaction rate and apatite forming ability when bioactive glass layer is present on the HA films.

Hydroxyapatite/Bioactive Glass Films Produced by a Sol–Gel Method: In Vitro Behavior

Microstructural changes in sol-gel derived hydroxyapatite thin films associated with Mn and Si co-substitution are investigated. The apatite-forming ability of fabricated thin films in simulated body fluid are found to be affected by changes in the crystallinity and formation of a more dissolvable calcium phosphate phase.

Muhammed Hasan Aslan

Papers

Fabrication of NiFe layered double hydroxide/reduced graphene oxide (NiFe-LDH/rGO) nanocomposite with enhanced sonophotocatalytic activity for the degradation of moxifloxacin

A Novel Label-Free Optical Biosensor Using Synthetic Oligonucleotides from E. coli O157:H7: Elementary Sensitivity Tests

Sintering behavior of ZnO:Al ceramics fabricated by sol‐gel derived nanocrystalline powders

Hydroxyapatite/Bioactive Glass Films Produced by a Sol–Gel Method: In Vitro Behavior

Microstructural Study of Mn and Si Co-substituted Hydroxyapatite Thin Films Produced by a Sol–Gel Method