Browsing by Subject "Particles"
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Item Open Access Bifunctional highly fluorescent hollow porous microspheres made of BaMoO4: Pr3+ nanocrystals via a template-free synthesis(The Royal Society of Chemistry, 2011) Yang, X.; Zhou, Y.; Yu, X.; Demir, Hilmi Volkan; Sun, X. W.We report a bifunctional hollow porous microsphere composed of single-component BaMoO4 : Pr3+ nanocrystals by a facile template-free synthesis. All the as-synthesized hollow microspheres are well-dispersed with a diameter of 2-4 mu m and the BaMoO4 : Pr3+ nanocrystals measure 30-60 nm in diameter. It is observed that there are a large amount of pores with an average diameter is 17.5 nm in the shell of these BaMoO4 : Pr3+ hollow microspheres, thereby exhibiting a great promise for drug delivery. Meanwhile, the strong, narrow-bandwidth red emission centered at 643 nm from these nanostructures can be efficiently excited from 430 nm to 500 nm. The combination of excellent luminescent properties and a hollow porous nanostructure suggest a great promise in the application of these nanostructures in lighting and displays, and in biomedicine such as targeted drug delivery, integrated imaging, diagnosis, and therapeutics. In addition, the template-free solution synthesis can be applied to the design and fabrication of other functional architectures.Item Open Access Enhancement of polycrystalline silicon solar cells efficiency using indium nitride particles(Institute of Physics Publishing Ltd., 2015) Alkis, S.; Chowdhury, F. I.; Alevli, M.; Dietz, N.; Yalızay, B.; Aktürk, S.; Nayfeh, A.; Okyay, Ali KemalIn this work, we present a hybrid indium nitride particle/polycrystalline silicon solar cell based on 230 nm size indium nitride particles (InN-Ps) obtained through laser ablation. The solar cell performance measurements indicate that there is an absolute 1.5% increase (Δη) in the overall solar cell efficiency due to the presence of InN-Ps. Within the spectral range 300-1100 nm, improvements of up to 8.26% are observed in the external quantum efficiency (EQE) and increases of up to 8.75% are observed in the internal quantum efficiency (IQE) values of the corresponding solar cell. The enhancement in power performance is due to the down-shifting properties of the InN-Ps. The electrical measurements are supplemented by TEM, Raman, UV/VIS and PL spectroscopy of the InN-Ps. © 2015 IOP Publishing Ltd.Item Open Access Simulation of a Brownian particle in an optical trap(American Association of Physics Teachers, 2013) Volpe, G.; Volpe, G.Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution-a clear signature of their out-of-equilibrium nature- and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted. (C) 2014 American Association of Physics Teachers.