Energy Transfer Efficiency from ZnO-Nanocrystals to Eu3+ Ions Embedded in SiO2 Film for Emission at 614 nm

Abstract

In this work, we study the energy transfer mechanism from ZnO nanocrystals (ZnO-nc) to Eu3+ ions by fabricating thin-film samples of ZnO-nc and Eu3+ ions embedded in a SiO2 matrix using the low-cost sol-gel technique. The time-resolved photoluminescence (TRPL) measurements from the samples were analyzed to understand the contribution of energy transfer from the various ZnO-nc emission centers to Eu3+ ions. The decay time obtained from the TRPL measurements was used to calculate the energy transfer efficiencies from the ZnO-nc emission centers, and these results were compared with the energy transfer efficiencies calculated from steady-state photoluminescence emission results. The results in this work show that high transfer efficiencies from the excitonic and Zn defect emission centers is mostly due to the energy transfer from ZnO-nc to Eu3+ ions which results in the radiative emission from the Eu3+ ions at 614 nm, while the energy transfer from the oxygen defect emissions is most probably due to the energy transfer from ZnO-nc to the new defects created due to the incorporation of the Eu3+ ions.

Electron Transfer Going the Distance: Mn-Doped ZnSe as a Model Photocatalytic System

“…The time-resolved PL decay trace was fitted over this time range using a stretched exponential (Kohlrausch−Williams−Watts) function (black), which is commonly used to model NCs with non-single exponential PL decays 49−54 and doped NCs. 55 The form of the stretched exponential function…”

“…In contrast, the doped Mn:ZnSe nanocrystals exhibit a dramatically longer excited lifetime that is typical of similar Mn-doped nanocrystalline systems. ,, A time-resolved PL decay measurement out to a millisecond time delay on a linear scale appears in Figure S3 for reference. The time-resolved PL decay trace was fitted over this time range using a stretched exponential (Kohlrausch–Williams–Watts) function (black), which is commonly used to model NCs with non-single exponential PL decays − and doped NCs . The form of the stretched exponential function permits calculation of an average time constant ⟨τ⟩ from the time constant τ 0 and the stretching exponent β according to the expression , The best fit of the time-resolved PL decay trace of the doped Mn:ZnSe nanocrystals in chloroform revealed an average time constant of 270 ± 20 μs.…”

White Light Emission from Thin-Film Samples of ZnO Nanocrystals, Eu3+ and Tb3+ Ions Embedded in an SiO2 Matrix

“…The concentration of Eu 3+ and Tb 3+ ions in the white light emitting sample is systematically obtained in this work. This is a continuation of our previous works [17,18,23,24]. The white light emission was achieved by first fabricating various thin-film samples of ZnO-nc in SiO 2 with varying concentrations of Eu 3+ and Tb 3+ ions.…”

“…The samples were fabricated using an identical recipe described in our previous publications [17,18,23,24]. In all the twenty-six samples, the molar ratio of Zn:Si in the samples was maintained at 1:2.…”

“…There have been substantial studies demonstrating the energy transfer specifically from ZnO-nc to Eu 3+ ions [6,7,8,9,10,11,12,13,14,15,16,17,18] and also from ZnO-nc to Tb 3+ ions [19,20,21,22,23]. Previous works by our group have also reported on the study of the energy transfer mechanism, contribution and transfer efficiency from various ZnO-nc emission centers to Eu 3+ ions [17,18,24] and Tb 3+ ions individually [23]. Interestingly, there are very few works on co-doping both Eu 3+ ions and Tb 3+ ions together with ZnO-nc in the same SiO 2 matrix.…”