Photoluminescence Decay Dynamics and Mechanism of Energy Transfer in Undoped and Mn<SUP>2+</SUP> Doped ZnSe Nanoparticles

Abstract

Energy transfer dynamics in Mn2+-doped ZnSe nanoparticles have been studied by monitoring the photoluminescence using time-integrated and time-resolved spectroscopic techniques. Upon Mn2+ doping, static photoluminescence (PL) spectra show that the bandedge excitonic state is quenched and the characteristic Mn2+ emission appears at 584 nm. Picosecond PL kinetics and femtosecond transient absorption studies have both found that the Mn2+ doping substantially shortens the average lifetimes of the bandedge excitonic state as well as shallow trap states. The energy transfer from ZnSe to Mn2+ likely follows two mechanisms, one mediated through trap states and another without.

Manipulation of Irradiative Defects at MnSe and ZnSe Dopant–Host Interface

“…According to the energy difference in Figure 5b, both the absorption from Mn to ZnSe conduction band (inverse process 2) and the absorption from trap energy levels to ZnSe conduction band (inverse process 1) can occur. [13] Since the Mn dopant numbers (c) and the whole Mn de-excitation rate (k r-Mn + k n-Mn , or 1/τ Mn ) are similar for samples A and B, the difference in transient absorption results should be caused by the absorption at dopant-host interface defects (inverse process 1). The decay time in transient absorption is 17.5 ps for QD sample B, which is much faster than that of sample A (28.9 ps).…”

“…Figure 5b shows the energy levels of QDs. [13] The excited electrons on ZnSe conduction band can be deactivated by following processes. [12a] (1) Non-irradiative recombination between ZnSe band gap by a rate constant of k n-ZnSe .…”

Magnetic behavior of manganese-doped ZnSe quantum dots

“…2 High fluorescence efficiency along with magnetic ordering makes Mn an interesting transition element dopant [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] in the semiconductor nanoparticles. Recently, Mn-doped ZnSe nanoparticles [3][4][5][6][7][8][9][10] received much attention since it has the potential application for luminescent as well as spintronic devices. 1 Moreover, the number of Mn ions incorporated at substitutional sites can also modify the lattice parameters as well as the band gap of semiconducting materials.…”

Co-doping of Ag into Mn:ZnSe Quantum Dots: Giving Optical Filtering effect with Improved Monochromaticity

“…S2 in Supporting Information) show an average decay time of 22.5 ps for the Mn:ZnSe QDs and 10.5 ps for Ag,Mn:ZnSe QDs. In comparison to Mn:ZnSe QDs, the decreased decay time for Ag,Mn:ZnSe QDs means the presence of much faster relaxation process 28 : namely channel 5 in Fig. 6 .…”