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quantum materials
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Quantum dot development
1. 2. , 3. 4. 5.
6. 7. 8. 9.
10. 11. 12.
.
.
.
1.
.
Bulk ( > 60~70%)
.
2. ,
Tunable band gap band gap
optical filter
LED, display
: ,
Solar cell LED Telecom. biolabelling
.
3.
1)
( >80%, ~27nm)
2) Pb
tetrapod, ~26nm
3)
ZnS capping
(ESP) Slot-die coating /
-
-Slot-die coating (: Rq=13nm 1.2nm)
.
4.
e
h
e
h
Core/shell
CB
VB
CB
VB
e
h
Core/shell
CB
VB
(QY~%)
(QY ~ %)
-Lattice mismatch strain
-shell : < 2ML
(QY > 80%)
- strain -
.
4.
20 30 40 50 60 70-150
-100
-50
0
50
100
150
200
250
300
350
400
CdSe
Se:S=2:2
a=5.99
Se:S=1:3
a=5.93
Inte
nsit
y (
cp
s)
2Theta (deg.)
Cd/(S+Se) = 8
(anion-limited)
Cd(Se,S) Alloy
Change in lattice parameters cf. CdSe: a=6.077 Cd(Se,S) [Se:S=2:2]: a=5.991 Cd(Se,S) [Se:S=1:3]: a=5.93 CdS: a=5.811
X-ray diffraction of CdSeS NCs
Te Se Conc.
(Composition-gradient)
Cd/(Te+Se) >> 1 (anion-limited)
Composition of reactant
Core/shell-like structure (R.E. Bailey, S. Nie, JACS, 125, 7100, 2003)
Te Se Conc.
Reaction time
(Room light) (UV light, l~310nm)
Reaction time
500 550 600 650 700 750 8000.0
3.0k
6.0k
9.0k
12.0k
Em
issio
n in
ten
sit
y (
A.U
.)
Wavelength (nm)
Cd/(S+Se)=8
Cd/(S+Se)=2
Cd/(S+Se)=1
Cd(S,Se)
490nm excit. -Cd/(Se+S) Cd-Se Cd-S core shell
- ~ 27nm - (QY) : 80%
.
4.
20 30 40 50 60 70
(20
3)(1
12
)
(10
3)
(11
0)
(10
1)
(00
2)
x=0.05
x=0
x=0.10
x=0.20
2 theta (deg.)
(10
0)
x=0
50nm
x=0.05
50nm
x=0.2
50nm
Cd1-xPbxSe TEM
Cd1-xPbxSe:
-
-
- Pb
Undoped CdSe:
-
(: 2~3nm)
Pb-
.
4.
Cd1-xPbxSe:
- Anisotropic growth
- Tetrapod shape
(diameter ~ 2.4nm, length~ 20nm)
- Cubic core-hexagonal branch
0.35nm
hexagonal
cubic
5nm
ZnS capping:
- ZnS epitaxial growth
- Surface trap
- (QY~21%)
- FWHM: 26.7nm
400 500 600 700 8000
20
40
60
80
100
120
140
160
Cd0.95
Pb0.05
Se
Em
issio
n
Wavelength (nm)
Cd0.95
Pb0.05
Se/ZnS
QY=21.2%
400 500 600 700 8000
1
2
3
Ab
so
rban
ce
Wavelength(nm)
Cd0.95
Pb0.05
Se
Cd0.95
Pb0.05
Se/ZnS
.
4.
Syringe pump
Unwinder
Powder brake
Rotary encoder
Winder
DC motor
Slot-die
Flexible substrates
Multi-zone furnace
PET/ITO tape (40mm x 50m) ( )
( 2009.06.22 , 10-2009-0055407 )
:
Gas
.
4.
Slot-die coating
, coating speed die gap Rq~1.2nm
Rq~1.2nm Rq~13nm
(PET/ITO)
(TPD) coating
.
4.
.
5.
-
- () > 85%
- TDPA Oleic acid
-
-
-
.
6.
Quantum dot; Technical status and market prospects, BCC Research (2008)
(: $3000~$10000/g)
- (2008): $28.6M (colloidal sol. only)
-5 (2013): $721.1M $721.1M optoelectronics (LED , $245.7M )
- ()
: (2006. 3 ), QD (2009. 4 )
-
: (), (), ,
.
10.
- ,
,
,
.
- (electronic device)
scale-up
-
,
.
.
12.
()
1. , , , ( , 2009 9 14, 10-2009-0055407))
2. , , , ( , 2009 6 22, 10-2009 -0055407)) 3. , , , ( , 2009 7 16, 10-2009-0064705)
()
1. , , , Hole transporting layer for light emitting devices and solar cells and method for manufacturing the same ( PCT , 2009 9 17, PCT/KR2009/005309)