The synthesis of Al and Fe codoped ZnO colloidal nanocrystals (NCs) using a modified etching-regrowth-doping method is presented. We show that the spectroscopic signatures associated with Fe3+ in ZnO disappear upon introduction of Al3+ donor defects into the ZnO lattice. The presence of Al3+ is confirmed by the appearance of a localized surface plasmon resonance feature indicating excess free carriers in the codoped NCs. These spectral changes suggest that Al3+ doping results in a reduction of Fe3+ dopants to the electron paramagnetic resonance-silent Fe2+ dopants that are stable under ambient conditions. These colloidal NCs provide a potential building block for manipulating magneto-optical properties and plasmon responses in colloidal NCs and higher-order nanostructures.
REFERENCES
1.
M.
Shim
and P.
Guyot-Sionnest
, “n-type colloidal semiconductor nanocrystals
,” Nature
407
(6807
), 981
–983
(2000
).2.
W. K.
Liu
, K. M.
Whitaker
, K. R.
Kittilstved
, and D. R.
Gamelin
, “Stable photogenerated carriers in magnetic semiconductor nanocrystals
,” J. Am. Chem. Soc.
128
(12
), 3910
–3911
(2006
).3.
A. M.
Schimpf
, S. T.
Ochsenbein
, R.
Buonsanti
, D. J.
Milliron
, and D. R.
Gamelin
, “Comparison of extra electrons in colloidal n-type Al3+-doped and photochemically reduced ZnO nanocrystals
,” Chem. Commun.
48
(75
), 9352
–9354
(2012
).4.
A. M.
Schimpf
, C. E.
Gunthardt
, J. D.
Rinehart
, J. M.
Mayer
, and D. R.
Gamelin
, “Controlling carrier densities in photochemically reduced colloidal ZnO nanocrystals: Size dependence and role of the hole quencher
,” J. Am. Chem. Soc.
135
(44
), 16569
–16577
(2013
).5.
R.
Buonsanti
, A.
Llordes
, S.
Aloni
, B. A.
Helms
, and D. J.
Milliron
, “Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals
,” Nano Lett.
11
, 4706
–4710
(2011
).6.
S. T.
Ochsenbein
, Y.
Feng
, K. M.
Whitaker
, E.
Badaeva
, W. K.
Liu
, X.
Li
, and D. R.
Gamelin
, “Charge-controlled magnetism in colloidal doped semiconductor nanocrystals
,” Nat. Nanotechnol.
4
(10
), 681
–687
(2009
).7.
A. M.
Schimpf
, J. D.
Rinehart
, S. T.
Ochsenbein
, and D. R.
Gamelin
, “Charge-state control of Mn2+ spin relaxation dynamics in colloidal n-type Zn1−xMnxO nanocrystals
,” J. Phys. Chem. Lett.
6
(9
), 1748
–1753
(2015
).8.
D.
Zhou
and K. R.
Kittilstved
, “Control over Fe3+ speciation in colloidal ZnO nanocrystals
,” J. Mater. Chem. C
3
(17
), 4352
–4358
(2015
).9.
D.
Zhou
and K. R.
Kittilstved
, “Electron trapping on Fe3+ sites in photodoped ZnO colloidal nanocrystals
,” Chem. Commun.
52
(58
), 9101
–9104
(2016
).10.
C. K.
Brozek
, D. M.
Zhou
, H. B.
Liu
, X. S.
Li
, K. R.
Kittilstved
, and D. R.
Gamelin
, “Soluble supercapacitors: Large and reversible charge storage in colloidal iron-doped ZnO nanocrystals
,” Nano Lett.
18
(5
), 3297
–3302
(2018
).11.
D.
Zhou
, P.
Wang
, C. R.
Roy
, M. D.
Barnes
, and K. R.
Kittilstved
, “Direct evidence of surface charges in n-type Al-doped ZnO
,” J. Phys. Chem. C
122
(32
), 18596
–18602
(2018
).12.
N. R.
Jana
, Y. F.
Chen
, and X. G.
Peng
, “Size- and shape-controlled magnetic (Cr, Mn, Fe, Co, Ni) oxide nanocrystals via a simple and general approach
,” Chem. Mater.
16
(20
), 3931
–3935
(2004
).13.
R.
Hufschmid
, H.
Arami
, R. M.
Ferguson
, M.
Gonzales
, E.
Teeman
, L. N.
Brush
, N. D.
Browning
, and K. M.
Krishnan
, “Synthesis of phase-pure and monodisperse iron oxide nanoparticles by thermal decomposition
,” Nanoscale
7
(25
), 11142
–11154
(2015
).14.
Y.
Xu
, J.
Sherwood
, Y.
Qin
, R. A.
Holler
, and Y.
Bao
, “A general approach to the synthesis and detailed characterization of magnetic ferrite nanocubes
,” Nanoscale
7
(29
), 12641
–12649
(2015
).15.
R. W. G.
Wyckoff
, “Würtzite ZnO (zincite)
,” in Crystal Structures
, 2nd ed. (Interscience Publishers
, New York
, 1963
).16.
R. D.
Shannon
, “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides
,” Acta Crystallogr., Sect. A
32
, 751
–767
(1976
).17.
E. A.
Meulenkamp
, “Synthesis and growth of ZnO nanoparticles
,” J. Phys. Chem. B
102
(29
), 5566
–5572
(1998
).18.
R. T.
Senger
and K. K.
Bajaj
, “Optical properties of confined polaronic excitons in spherical ionic quantum dots
,” Phys. Rev. B
68
(4
), 045313
(2003
).19.
A. P.
Roth
, J. B.
Webb
, and D. F.
Williams
, “Absorption edge shift in ZnO thin films at high carrier densities
,” Solid State Commun.
39
(12
), 1269
–1271
(1981
).20.
E.
Della Gaspera
, A. S. R.
Chesman
, J.
van Embden
, and J. J.
Jasieniak
, “Non-injection synthesis of doped zinc oxide plasmonic nanocrystals
,” ACS Nano
8
(9
), 9154
–9163
(2014
).21.
R. J.
Mendelsberg
, G.
Garcia
, H.
Li
, L.
Manna
, and D. J.
Milliron
, “Understanding the plasmon resonance in ensembles of degenerately doped semiconductor nanocrystals
,” J. Phys. Chem. C
116
(22
), 12226
–12231
(2012
).22.
H.
Kaftelen
, K.
Ocakoglu
, R.
Thomann
, S.
Tu
, S.
Weber
, and E.
Erdem
, “EPR and photoluminescence spectroscopy studies on the defect structure of ZnO nanocrystals
,” Phys. Rev. B
86
(1
), 014113
(2012
).23.
H.
Zhou
, A.
Hofstaetter
, D. M.
Hofmann
, and B. K.
Meyer
, “Magnetic resonance studies on ZnO nanocrystals
,” Microelectron. Eng.
66
(1-4
), 59
–64
(2003
).24.
W. K.
Liu
, K. M.
Whitaker
, A. L.
Smith
, K. R.
Kittilstved
, B. H.
Robinson
, and D. R.
Gamelin
, “Room-temperature electron spin dynamics in free-standing ZnO quantum dots
,” Phys. Rev. Lett.
98
(18
), 186804
(2007
).25.
W. M.
Walsh
and L. W.
Rupp
, “Paramagnetic resonance of trivalent Fe57 in zinc oxide
,” Phys. Rev.
126
(3
), 952
–955
(1962
).26.
A. M.
Schimpf
and D. R.
Gamelin
, “Thermal tuning and inversion of excitonic Zeeman splittings in colloidal doped CdSe quantum dots
,” J. Phys. Chem. Lett.
3
(10
), 1264
–1268
(2012
).27.
W. L.
Harrigan
and K. R.
Kittilstved
, “Reversible modulation of the Cr3+ spin dynamics in colloidal SrTiO3 nanocrystals
,” J. Phys. Chem. C
122
, 26652
–26657
(2018
).28.
J. M. D.
Coey
, P.
Stamenov
, R. D.
Gunning
, M.
Venkatesan
, and K.
Paul
, “Ferromagnetism in defect-ridden oxides and related materials
,” New J. Phys.
12
(5
), 053025
(2010
).29.
J. M. D.
Coey
, K.
Wongsaprom
, J.
Alaria
, and M.
Venkatesan
, “Charge-transfer ferromagnetism in oxide nanoparticles
,” J. Phys. D: Appl. Phys.
41
(13
), 134012
(2008
).© 2019 Author(s).
2019
Author(s)
You do not currently have access to this content.
