Size depended electrical properties of Hydroxyapatite nanoparticles

Bystrov, Vladimir; Bystrova, N.; Dekhtyar, Yu.; Карлов, А. В.; Katashev, Alexei; Meißner, Christian; Paramonova, Ekaterina; Polyaka, N.; Sapronova, Alla

doi:10.1007/978-3-642-03887-7_64

Cited by 10 publications

(16 citation statements)

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“…The magnitudes of the experimentally measured work function were directly proportional to the typical sizes of NPs (Fig. 10,b) [30,48], which are in accordance with the above simulation results in respect of P values, when the cluster size is larger.…”

supporting

confidence: 87%

“…The results obtained confirm and clarify the mechanism of the earlier discovered size effect of HAP NPs, which is related to the electrical properties of HAP NPs (dipole moment, polarization, surface potential and electron work function) [37][38][39][40]48]. Second, the interaction of HAP NPs and the resultant shapes of their growth and aggregation directly depend on the concentration of hydrogen atoms (or protons) in the surrounding media, which usually determines pH.…”

Section: Figsupporting

confidence: 71%

“…So, in this case, the change of the surface energy level and corresponding work function shift must be estimated as: This value is close to the shift of the electron work function ϕexp = 0.3 eV directly measured by photoelectron spectroscopy. A derivation of the emission current for a photon energy demonstrated a sharp maximum at 5.2 eV for sizes in the range ≈ 20-60 nm, while NPs with a size range > ∼ 100 nm indicated the maximum at 5.5 eV [30,35,48] (Fig. 10,a).…”

mentioning

confidence: 99%

“…For HAP NPs with the size x ∼ 5 nm this shift of energy on the NPs' surface ΔE = Eel × x ∼ 0.14-0.15 eV. For the experimental data for HAP NPs [30,35,48] with size variations between two NPs of ∼ 20-60 nm and sizes of more than ∼ 100 nm, the average differences in the effective radii of these two compared NP classes could be estimated as Δx ∼ 10-20 nm. So, in this case, the change of the surface energy level and corresponding work function shift must be estimated as: This value is close to the shift of the electron work function ϕexp = 0.3 eV directly measured by photoelectron spectroscopy.…”

mentioning

confidence: 99%

“…This internal electric field must shift the entire energy band structure of the HAP NPs; the largest shift evidently influences the surface energy levels. In this model the shift of the surface level energy under the influence of the internal electric field depends on the NP size and consequently on the corresponding change of the electron work function for NPs with size variation (as estimated in [30,[37][38][39]48]). …”

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confidence: 99%

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Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Bystrov¹

2017

Math.Biol.Bioinf.

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Abstract. In this review paper the main approaches to modeling the hydroxyapatite (HAP) structures and first-principle calculations of their properties, pure and with various defects, are considered. First, the HAP nano-particles (NPs) and clusters peculiarities are described using different methods: molecular mechanical and quantum mechanical, especially semi-empirical such as PM3. Both approximations used here, namely, restricted Hartee-Fock (RHF) and unrestricted Hartee-Fock (UHF), are considered. The influence of the protons (hydrogens), contained in the surrounding medium (pH), on the formation of HAP nanoparticles of various sizes and shapes is considered and discussed. Second, the HAP crystal unit cells studies are considered on the basis of a density functional theory (DFT) modelling. The main peculiarities of both phases (hexagonal and monoclinic) are considered too, including their ordered and disordered substructures. One of the important aspects of the computer modeling of HAP is to build the models and consider various structural modifications of HAP (such as, vacancies of oxygen atoms and hydroxyl OH group, hydrogen interstitials and different substitutions of atoms in HAP unit cell), which allow explicitly creating and exploring the changes in the charges of HAP and the electrical potential on the HAP surface. HAP modifications are most close to biological HAP and therefore are necessary for implant medical applications and can create and functionalize HAP surface with most adhesive properties for living cells (osteoblasts, osteoclatst). This improves the HAP implant quality. Besides, it has recently been established that oxygen vacancy in HAP influences their photo-catalytic properties. It is important for HAP usage as in environmental remediation and for bacteria inactivation. Therefore it is very important to create and investigate the oxygen vacancy models in HAP, and others defects models. In this work we review a DFT modelling and studies of HAP, both pure perfect bulk and imperfect bulk cases. Special HAP modelling approaches are used for layered slab super-cells units, which include vacuum spaces between the layered slabs forming HAP surface. To all these computer studies the first principle calculations were applied. In this review various DFT approximations are analysed for bulk and surface modified HAP. These approximations are carried out using both the local basis (local density approximation -LDA, in AIMPRO codes) and the plane-waves (generalized gradient approximation -GGA, in VASP codes). Data of all structures and models of HAP defects investigated are widely analyzed.

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confidence: 87%

Section: Figsupporting

confidence: 71%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Bystrov¹

2017

Math.Biol.Bioinf.

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Electrical Functionalization and Fabrication of Nanostructured Hydroxyapatite Coatings

Bystrov

Bystrova

Dekhtyar

et al. 2019

Bioceramics and Biocomposites

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High‐Performance Top‐Gated Organic Field‐Effect Transistor Memory using Electrets for Monolithic Printed Flexible NAND Flash Memory

Baeg

Khim

Kim

et al. 2012

Adv Funct Materials

192

186

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High‐performance top‐gated organic field‐effect transistor (OFET) memory devices using electrets and their applications to flexible printed organic NAND flash are reported. The OFETs based on an inkjet‐printed p‐type polymer semiconductor with efficiently chargeable dielectric poly(2‐vinylnaphthalene) (PVN) and high‐k blocking gate dielectric poly(vinylidenefluoride‐trifluoroethylene) (P(VDF‐TrFE)) shows excellent non‐volatile memory characteristics. The superior memory characteristics originate mainly from reversible charge trapping and detrapping in the PVN electret layer efficiently in low‐k/high‐k bilayered dielectrics. A strategy is devised for the successful development of monolithically inkjet‐printed flexible organic NAND flash memory through the proper selection of the polymer electrets (PVN or PS), where PVN/‐ and PS/P(VDF‐TrFE) devices are used as non‐volatile memory cells and ground‐ and bit‐line select transistors, respectively. Electrical simulations reveal that the flexible printed organic NAND flash can be possible to program, read, and erase all memory cells in the memory array repeatedly without affecting the non‐selected memory cells.

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Size depended electrical properties of Hydroxyapatite nanoparticles

Cited by 10 publications

References 1 publication

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Компьютерные Исследования Наноструктур Гидроксиапатита, Их Особенности И Свойства

Electrical Functionalization and Fabrication of Nanostructured Hydroxyapatite Coatings

High‐Performance Top‐Gated Organic Field‐Effect Transistor Memory using Electrets for Monolithic Printed Flexible NAND Flash Memory

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