Tomar M.S. – TechConnect Briefs

Multifunctional Fe3O4/ZnO core-shell nanoparticles for photodynamic therapy

Beltran J.C., Tomar M.S., Singh S.P., Perales O., Rivera L., Peña S., University of Puerto Rico-Mayagüez, PR

The photodynamic therapy (PDT) based on core-shell structures require efficient luminescence within specific wavelength range, preferably in near infrared. In the present study we aim to create a multifunctional platform for PDT through Fe3O4/ZnO core [...]

Low-Temperature Polyol Synthesis of Nanocrystalline Co and CoPt Alloys

Chávarri-Pajares E., Pérez J., Perales-Perez O., Singhal R., Tomar M.S., University of Puerto Rico, PR

The strong size-dependent magnetic properties of transition metal nanocrystals can be used to estimate the scaling limits of magnetic storage, a key component of information technology. High Ku (magnetocrystalline anisotropy constant) materials become then very [...]

Zinc Sulfide and Cadmium Sulfide based Nanocrystals and Shells

Balaguera M., Perales-Perez O., Rivera-Montalvo L., Singhal R., Tomar M.S., University of Puerto Rico, PR

The objective of the current research is to synthesize CdS, ZnS nanocrystals through a two phases-method were quantum dots moved from the aqueous phase to the organic one after proper coating of the particles by [...]

Effect of Reaction Temperature on the Structural and Optical Properties of Zno Nanocrystals

Parra-Palomino A., Sotomayor C., Perales-Perez O., Singhal R., Voyles P., Tomar M.S., University of Puerto Rico, PR

The present research addressed the size-controlled synthesis of ZnO nanocrystals at different temperatures. In order to study systematically the dependence of crystal size with synthesis conditions in ethanol, stable suspensions of these nanocrystals were produced [...]

Low-Temperature Synthesis and Characterization of Fe-Doped ZnO Nanocrystals

Parra-Palomino A., Singhal R., Perales-Perez O., Tomar M.S., University of Puerto Rico, PR

We present here our results on synthesis and characterization of bare and Fe-doped ZnO nanocrystals by a modified sol-gel method, which does not require annealing of the samples. Metal acetate solutions in 2-ethylhexanoic acid were [...]

Optimization of Magnetic Properties in Cobalt Ferrite Nanocrystals

Cedeño Y., Perales-Perez O., Roman F., Singhal R., Tomar M.S., University of Puerto Rico, Mayaguez Campus, PR

Among the various ferrite materials for magnetic recording applications, cobalt ferrite (CoFe2O4) possesses excellent chemical stability and good mechanical hardness. Furthermore, the large positive first order crystalline anisotropy constant has made this ferrite a promising [...]

Synthesis and Magnetic Properties of Polyaniline-Based Magnetic Nanocomposites for EMI Applications

Renteria B., Singhal R., Calderon E., Tomar M.S., Banerjee J., University of Puerto Rico, PR

we have synthesized composite of polyaniline (PANI) with manganese-zinc-ferrite (MnXZn1-XFe2O4) nanoparticles. PANI was synthesized by polymerization of aniline in the presence of ammonium peroxydisulfate and HCl. Electrical conductivity of bare PANI pellets averaged 0.8044 (Ω·m)-1. [...]

Rare Earth-Substituted BI 4Ti3O12 Nanocrystalline Thin Films: Synthesis and Ferroelectric Characterization

Tomar M.S., Katiyar R.S., Perales-Perez O., University of Puerto Rico, Mayaguez Campus, PR

In this work we present the synthesis of bare and rare earth (Ce,Er,Pr)-doped Bi4Ti3O12 (BIT) nanocystalline thin films using a method based on the Sol-Gel process. Thin films were deposited by spin coating on Pt [...]

Low-Temperature Synthesis and Magnetic Characterization of Doped-ZnS Nanostructures

Dussan Devia S., Tomar M.S., Morales L.M., Mata O., Jia W., University of Puerto Rico, Mayaguez Campus, PR

Nanostructured DMSs are of great importance due to potential applications in spintronics and photo-electronic devices. Recent studies propose that ZnS doped with transition metal ions can exhibit ferromagnetic behavior at room temperature. The present work [...]

Room-Temperature Synthesis and Characterization of Highly Monodisperse Transition Metal-Doped ZnO Nanocrystals

Singh S.P., Perales-Perez O., Tomar M.S., Parra-Palomino A., Ruiz-Mendoza A., University of Puerto Rico, PR

We present here the results of our current efforts on size-controlled synthesis of bare and Mn- and Co-doped ZnO nanocrystals. Stable suspensions of these materials were produced in ethanol solutions at room-temperature. XRD characterization of [...]