University of PardubiceFaculty of Chemical Technology

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Blue-, green-emitting gradient alloyed Cd-Zn-S-Se quantum dots: the temperature influence on the size and optical properties

Authors: Grinco Marina | Loghina Liudmila | Šlang Stanislav | Iakovleva Anastasia | Pálka Karel | Vlček Miroslav

Year: 2018

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Blue-, green-emitting gradient alloyed Cd-Zn-S-Se quantum dots: the temperature influence on the size and optical properties	Over the past years, the synthesis of semiconductor quantum dots (QDs) has provided a great attention by scientist due to their size dependent optical and electronic properties. They has become a suitable light emitting basis for photonic and optoelectronic applications [1]. In the present work, a facile way of synthesis of highly luminescent blue- and green-emitting gradient alloyed Cd-Zn-S-Se QDs is presented. Quaternary QDs were synthesized using a hot-injection method that was developed in our laboratory [2]. For the QDs nucleation and growth, cadmium and zinc oleates were used as source of cadmium and zinc; in turn the trioctylphosphine sulfide and selenide were introduced as sulfur and selenium precursors. Key issues at the study had been to investigate a temperature influence on the size and optical properties of obtained QDs and to determine optimal conditions for their synthesis. For this purpose, all experiments were carried out under the same conditions (the Cd/Zn, S/Se precursors molar ratio and their concentration remained constant), with exception of change of temperature which was chosen as a variable factor. The temperature range was set between 245 °С and 305 °С with 15 °С step. The QDs growth was monitored by set of aliquots taken out at exact time intervals for spectroscopic measurements. As a result, the optical properties of synthetized QDs were different. The photoluminescence (PL) intensity was increasing with increasing of reaction temperature up to 290 °C after which a small decay was observed at 305 °C. Besides, the increasing of reaction temperature lead to a slight shift of the absorption and PL peaks maxima into ultraviolet region. The observed change in the optical properties of synthetized alloys could be explained by difference in reactivity of utilized Cd, Zn and S, Se precursors during chemical process and, as a consequence by the different elemental content in the final composition. All prepared gradient alloyed Cd-Zn-S-Se QDs poss	quantum dots; semiconductors; temperature; optical properties; quaternary Cd-Zn-S-Se alloy