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)