Intense photoluminescence from Cu-doped CdSe nanotetrapods triggered by ultrafast hole capture

Abstract

Brightly photoluminescent Cu-doped CdSe nanotetrapods (NTPs) have been prepared by a modified hot injection method. Their photoluminescence (PL) has a quantum yield of 38% and decays slowly over a few...

Exciton Dynamics in Colloidal CdS Quantum Dots with Intense and Stokes Shifted Photoluminescence in a Single Decay Channel

“…To this effect, weakly emissive CdSe nanotetrapods 43,44 have been doped with Cu + to obtain a dramatic enhancement in PL intensity and lifetime. 45 On the one hand, water-soluble nanotetrapods, prepared by ligand exchange, are found to be nonemissive. 46 On the other hand, polyethylenimine (PEI)-capped CdS QDs, prepared in an aqueous medium, are found to exhibit a strong and long-lived trap emission, which is significantly Stokesshifted.…”

“…49 It is similar to the PLQY of water-soluble PEI-capped CdS QDs 39,47 and oleicacid capped CdSe nanotetrapods. 45 The large Stokes shift, with an apparent value of 0.46 eV, indicates the involvement of trap states. 50 The significant spectral width (full width at halfmaximum (fwhm) = 100 nm) of PL can be attributed to exciton−phonon coupling.…”

“…In recent times, our group has launched a quest for QDs with high quantum yield and long PL lifetime. To this effect, weakly emissive CdSe nanotetrapods , have been doped with Cu + to obtain a dramatic enhancement in PL intensity and lifetime . On the one hand, water-soluble nanotetrapods, prepared by ligand exchange, are found to be nonemissive .…”

“…To the best of our knowledge, the observed PLQY of 38% is greater than all but one earlier report on CdS QDs in CHCl 3 . It is similar to the PLQY of water-soluble PEI-capped CdS QDs , and oleic-acid capped CdSe nanotetrapods . The large Stokes shift, with an apparent value of 0.46 eV, indicates the involvement of trap states .…”

Impacts of Dopant and Post-Synthetic Heat-Treatment on Carrier Relaxation of Cu2+-Doped CdSe Nanoplatelets

“…The BE carrier lifetime of NPLs decreases from 0.84 ± 0.04 to 0.34 ± 0.02 ns after doping Cu ions in CdSe NPLs (Table S1, Figure 3b), and it further reduces to 0.29 ± 0.01 ns after post-synthetic heat treatment of Cu-doped CdSe NPLs at 55 °C for 36 h. It is due to the additional pathway for charge extraction from CB of CdSe NPLs. 40 The longer PL decay time of Cu 2+ emission in Cu 2+ -doped CdSe QDs 41 and CdSe/ZnSe QDs is reported due to weak spatial overlap between the conduction-band electron wave function and the localized copper state. 23 The red emission arises due to the recombination of the electron at CB minima of CdSe NPLs to the permanent holes present at the localized Cu d-state.…”