Synthesis and Properties of Water-Soluble Blue-Emitting Mn-Alloyed CdTe Quantum Dots

Abstract

In this work, we prepared CdTe quantum dots, and series of Cd1-xMnxTe-alloyed quantum dots with narrow size distribution by an ion-exchange reaction in water solution. We found that the photoluminescence peaks are shifted to higher energies with the increasing Mn2+ content. So far, this is the first report of blue-emitting CdTe-based quantum dots. By means of cyclic voltammetry, we detected features of electrochemical activity of manganese energy levels formed inside the Cd1-xMnxTe-alloyed quantum dot band gap. This allowed us to estimate their energy position. We also demonstrate paramagnetic behavior for Cd1-xMnxTe-alloyed quantum dots which confirmed the successful ion-exchange reaction.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2529-y) contains supplementary material, which is available to authorized users.

Multi-channel electroluminescence of CdTe/CdS core-shell quantum dots implemented into a QLED device

“…The oxygen dissolved in the reaction media was removed from the system by an argon flow during 10 min. The average size of the CdTe quantum dots prepared at this stage is about 2.3±0.3nm in accordance with the TEM data [22] and spectroscopic measurements [13]. To provide growth and stabilization of a CdS shell around the CdTe QD freshly obtained solution of CdTe QD was kept at 100°C for 8 h. The resulting size of the CdTe/CdS quantum dots is about 3.3 nm that follows from optical spectroscopy data and cyclic voltammetry measurements [23].…”

“…The applied voltage induces a charge carrier transfer into the core overcoming the barrier between the CB of the CdS shell and the CdTe core (Figure 5b). However, the EL band at 530 nm is slightly blue shifted comparing with that band in the PL spectrum of CdTe/CdS QDs of the same size (545 nm [22], 560 nm [25]). That can probably be explained by the strain-induced band shift effect which means that the growth of CB edge level of the CdTe core is affected by the growing of the shell thickness [40].…”

“…The EL spectrum can be explained by the mixed type-I and type-II behavior of CdTe/CdS core/shell QDs upon the excitation by injection of holes and electrons into the QD active layers (Figure 5b). The most intensive EL band at 530 nm (arrow 1 in figure 5b) corresponds to the emissive recombination of holes and electrons in the CdTe core which is typical for type-I core-shell QDs [22]. The applied voltage induces a charge carrier transfer into the core overcoming the barrier between the CB of the CdS shell and the CdTe core (Figure 5b).…”

Chemistry of nanomaterials in Ukraine: per aspera

“…[18] Similarly quantum dots of A2B6 semiconductors became an object of interest of the groups experienced in bulk materials. Considerable success was achived in the quantum, dots synthesis and application including CdTe, [19,20] CdSe, [21] CdS [22] and AgInS2. [23] CdTe/CdS core-shell quantum dots implemented into a light emitting device demonstrated multi-channel electroluminescence with a light-green emission color.…”