Mixing of Excitons in Nanostructures Based on a Perylene Dye with CdTe Quantum Dots

Abstract

Semiconductor quantum dots of the A2B6 group and organic semiconductors have been widely studied and applied in optoelectronics. This study aims to combine CdTe quantum dots and perylene-based dye molecules into advanced nanostructure system targeting to improve their functional properties. In such systems, new electronic states, a mixture of Wannier–Mott excitons with charge-transfer excitons, have appeared at the interface of CdTe quantum dots and the perylene dye. The nature of such new states has been analyzed by absorption and photoluminescence spectroscopy with picosecond time resolution. Furthermore, aggregation of perylene dye on the CdTe has been elucidated, and contribution of Förster resonant energy transfer has been observed between aggregated forms of the dye and CdTe quantum dots in the hybrid CdTe-perylene nanostructures. The studied nanostructures have strongly quenched emission of quantum dots enabling potential application of such systems in dissociative sensing.

Core and Shell Contributions to the Phonon Spectra of CdTe/CdS Quantum Dots

“…By varying the duration of the thermal treatment during the synthesis, the electrical current, the pH of the medium or the TGA concentration and some other parameters, the spectral position of the PL can be tuned and its intensity maximized. The characterization of the optical properties of the CdTe NCs obtained by this method was partially reported by us earlier [26][27][28]. Here, we report the representative vibrational properties of such NCs, studied by resonant Raman spectroscopy and FTIR spectroscopy in the far-infrared range.…”

“…The methods of colloidal synthesis of CdTe NCs using thioglycolic acid (TGA) as a stabilizer of the NCs in the colloid is a facile and scalable route that is broadly used to obtain highly fluorescent NCs at a relatively low temperature in water [26][27][28][29][30]34]. By varying the duration of the thermal treatment during the synthesis, the electrical current, the pH of the medium or the TGA concentration and some other parameters, the spectral position of the PL can be tuned and its intensity maximized.…”

“…The synthesis and optical properties of aqueous colloidal CdTe NCs of such type as those used in this work were partially described by us earlier [26][27][28]. Briefly, the process of CdTe synthesis was accomplished at 20 • C in argon atmosphere with the use of the following reagents: 0.1 M solution of CdI 2 (reagent grade), thioglycolic acid (TGA) (99%), and electrochemically prepared hydrogen telluride.…”

“…Here, we report the results of a Raman study of CdTe NCs synthesized by a facile scalable route in water, using thioglycolic acid (TGA) as a stabilizer of the NCs in the colloid [26][27][28]. We show that using thiol during the synthesis results in the formation of a CdS shell around the CdTe core NCs.…”

“…The spectra of bare CdTe NCs were studied in some works [25], although much less intensively compared to CdSe and CdS ones (see recent reviews [11,12]). In view of the continuous interest of researchers in the employment of the optical properties of CdTe NCs in general [1,2] and those synthesized in aqueous solution using thiol stabilizer in particular [1,3,[26][27][28][29][30], deeper insight into their structural and vibrational properties is required.…”