Luminescence decay characteristics of CdS quantum dots doped with europium ions

• Published in: Journal of luminescence Vol. 213; pp. 459 - 468
• Main Authors: Smirnov, M.S., Ovchinnikov, O.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2019
• Subjects: Europium thenoyltrifluoroacetonate; Non-radiative energy transfer; Quantum dots; Trap state luminescence; Non-radiative energy transfer; Europium thenoyltrifluoroacetonate; Trap state luminescence; Quantum dots
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2019.05.046

In the present paper, we present an analysis of the luminescence decays for colloidal quantum dots (QDs) with interfaces doped with Eu3+ ions of the corresponding thenoyltrifluoroacetone complexes. The luminescence decay features related to concentration and temperature effects are considered. The Stern-Volmer plots obtained at 300 and 77 K for the trap state luminescence of CdS:Eu3+ QDs show that the QD luminescence quenching is of a dynamic character with the Stern-Volmer constant being Kdyn=3.7⋅105 M−1. Non-radiative excitation energy transfer from the trap state luminescence centers in CdS quantum dots to Eu3+ ions is observed. In addition, the value of the quenching rate kdyn=2.37⋅1013s−1⋅M−1 indicates that the energy transfer process has a non-diffusive nature. This conclusion is supported by the effective quenching in a frozen solution at 77 K where there is no diffusion. For CdS/TGA QDs doped with europium ions, we observe a significant increase in the luminescence lifetime (from 190 μs to 346 μs) for the band peaked at about 615 nm as compared to the free Eu:TTA complex. We conclude that Eu3+ ions are incorporated into the QD interfaces.