Crystal Structure and Optical Properties of CuInS2 Nanocrystals in a Glass Matrix

Abstract

Glasses containing nanometer sized particles of CuInS 2 (10 to 70 nm) were fabricated and characterized. The lattice structure of nanoparticles determined by X-ray diffraction is different from bulk CuInS 2 that can provide features of optical properties of the glasses. This change of lattice is proposed as a possible reason for the low-energy shift of the fundamental absorption edge observed for nanoparticles as compared with bulk CuInS 2 .

Preparation of Ultrafine Chalcopyrite Nanoparticles via the Photochemical Decomposition of Molecular Single-Source Precursors

“…Similar color transitions were observed by Czekelius et al during the reaction of bis(trimethylsilyl) sulfide with a mixture of Cu(I)−P(OPh) 3 and In(III)−P(OPh) 3 complexes to form CuInS 2 colloids 6f. In that case and in the thermal decomposition of (R 3 P) 2 CuIn(SR‘) 4 precursors, 8c,d a deep red color is observed, which is never attained in the photochemical decomposition of these precursors, even with 218 h of irradiation.

1 Vials of samples from the irradiation of 20 mM solutions of precursor 1 in DOP for (from left to right) 0, 2, 4, 6, 8, 11, 21, 30, 50, 74, 124, and 218 h.

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“…Different approaches to the synthesis of chalcopyrite nanoparticles have been reported; , however, only a couple have achieved particle sizes small enough to exhibit quantum confinement (the Wannier−Mott bulk exciton radius of CuInS 2 is 8 nm 6f ), and in most the nanoparticle size distribution is broad. The theoretical limit for quantum dot solar cells is based on an ordered array of nanoparticles with a narrow size distribution (≤10% size variation).…”

“…Compounds with the general formula [(LR 3 ) 2 CuM(ER‘) 4 ] (L = P, As; E = S, Se; M = In, Ga; R = aryl, alkyl; R‘ = alkyl) , have been used as single source precursors for chemical vapor deposition of chalcopyrite thin films. They have also been used to produce chalcopyrite nanoparticles with some measure of size control via their thermal decomposition in dioctyl phthalate (DOP) at 200−300 °C in the presence of a thiol capping agent. 8c,d Herein, we describe the photochemical decomposition of related precursors as a means of producing even smaller, more crystalline chalcopyrite nanoparticles with a narrower size distribution. Detailed characterization of the particles by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy energy dispersive X-ray (SEM/EDX) analysis, powder X-ray diffraction (XRD), electron diffraction, inductively coupled plasma (ICP) spectroscopy, UV−vis absorption spectroscopy, and fluorescence spectroscopy has yielded some interesting phenomena associated with growth, size, composition, crystal structure, and concentration of the nanoparticles that are relevant to synthesis, characterization, and properties of semiconductor quantum dots in general.…”

New Generation Cadmium-Free Quantum Dots for Biophotonics and Nanomedicine

“…In analogy to the Bohr model of the hydrogen atom, it can be written as where ε is the dielectric constant of the semiconductor, ℏ is the reduced Planck constant, e is the charge of an electron, m e is the effective mass of the electron, and m h is the effective mass of the hole. Because the dielectric constant and effective masses of the hole and electron are material-dependent, the exciton Bohr radii for different semiconductors vary substantially (e.g., 2.3 nm for ZnO, 4.1 nm for CuInS 2 , 18 nm for PbS, and 46 nm for PbSe). When the radius of a semiconductor nanocrystal approaches the exciton Bohr radius, the motions of the electron and hole are confined, within the particle, to dimensions smaller than in the bulk .…”

About Modern Research in the Field of Complex Sulfide Compounds (State and Trends)

“…The research results of this complex compound are also reflected in the following works [31] in earlier studies [3,24,40,18,19,13,9,28,35,12]. 4.…”