On the Physico-Chemical Properties of ZnO Nanosheets Modified with Luminescent CdTe Nanocrystals

Abstract

ZnO nanosheets were synthesized through thermal decomposition of the Zn4CO3(OH)6·H2O precursor at increasing temperatures (i.e., 300, 400, and 500 °C), and a multidisciplinary characterization (carried out by X-ray diffraction, SEM and TEM microscopy, FTIR, diffuse reflectance UV–vis and photoluminescence spectroscopy, TGA, and nitrogen adsorption) allowed us to describe the dependence of the physicochemical properties of the final materials on the precursor decomposition temperature. Due to its interesting physicochemical properties (good electrical conductivity, adequate specific surface area, and significant concentration of surface OH groups suitable for sylilation reactions), the ZnO sample, prepared by thermal decomposition of Zn4CO3(OH)6·H2O at 400 °C (named ZnO400), was selected as the host solid for the introduction of guest luminescent CdTe nanocrystals. The modification of the ZnO surface with CdTe allowed us to change the optical properties of the final solid, resulting in a tuning of emission properties of the ZnO nanosheets.

General Route to ZnO Nanorod Arrays on Conducting Substrates via Galvanic-cell-based approach

“…The FTIR spectroscopy (Figure S5) further verifies our conjecture. The broad absorption peaks at 3405 cm −1 and 1639 cm −1 were assigned to the stretching and bending modes of OH groups, respectively31. After annealing, the intensity of the OH peaks becomes much lower, which is due to the dehydration of OH groups.…”

Covalent Surface Modification of Oxide Surfaces

“…+ /À [195] + + + + [137] R-OH [174] HA [80e] R-I [173] ITO [b,i,h] + /À [196] + + [62b, 197] + /À [198] + /À [199] + + [140] + [196b] R-SH [198] V/Cr/Steel [h,j] + + [50,200] + + [50,201] + /À [50] + [153] + /À [50,146] + [202] R-SH [203] SnO 2 + + [204] + + + + [205] ZnO + /À [206] + + [169] + + + [169] R-SH R-OH [169] WO 3 + + [207] + + [101] Cuprates + + [102] + [165,166] R-SH [102] Nb it aims to summarize the monolayer quality obtained per substrate for each of the attachment chemistries reviewed herein. In the first column, the type of surface is indicated together with "best-practice" methods to properly activate that surface towards a hydroxy-oriented surface modification.…”

Colloidal semiconductor nanocrystals: the aqueous approach

“…In both cases a proper functionalization of the substrate surface is necessary prior to coupling. For instance, in order to covalently link carboxyl-functionalized CdTe NCs to a glass substrate 147 or attach them via charge-charge interaction to a porous ZnO surface, 148 the substrates have been aminated with 3-(aminopropyl)triethoxysilane. Subsequent covalent binding has been realized via water soluble carbodiimide mediated amidation.…”