Metal-Semiconductor Hetero- Nanocrystals and Their Optoelectronic Properties Research Jiatao Zhang...

Metal-Semiconductor Hetero-Nanocrystals and Their Optoelectronic

Properties Research

Jiatao Zhang（张加涛）Beijing Institute of Technology

北京理工大学2015.10.13

Optoelectronics and nano energy

Green applicationGreen application

Lieber CM, Nature Materials 2007; Fan ZY, Chem. Soc. Rev. 2012.

Yang PD, Nature Mater. 2012 ； Jiang L, Small 2014.

Nanomaterials Chemistry Opportunities:

Nanophysics Nanochemistry

VS

Quantum size tuning

Morphology control

Composition tailoring

Crystallization engineering

Surface modification

Functionalities integration

Quantum size tuning

Morphology control

Composition tailoring

Crystallization engineering

Surface modification

Functionalities integration

Colloidal Qds and metal nanocrystals

CdSe core ZnS shell

TOPO coating

O P

Alivisatos (UC Berkeley), Bawendi (MIT), Brus (Columbia), Peng (Zhejiang U), Nie (Emory), Mirkin (Northwest), Xia (Washington), Yang (UC Berkeley), Wang (Hongkong)Alivisatos (UC Berkeley), Bawendi (MIT), Brus (Columbia), Peng (Zhejiang U), Nie (Emory), Mirkin (Northwest), Xia (Washington), Yang (UC Berkeley), Wang (Hongkong)

Integration of functionalities

E. H. Sargent, Nature 2015

E. H. Sargent, Nat. Mater. 2014.

Linic S, Nat. Mater. 2011.

Jiang L, Small 2014.

Ouyang M, Nat. Comm. 2014.

Wang JF, Adv. Mater., 2014.

• Light-Matter• Plasmon-Exciton• Light harvest• Photovoltaic • Photocatalysis• Photothermal

Plasmon

Exciton

Incident lightIsotropic Core/shell

Plasmon

Exciton

Incident light

Semi.

Heterodimer

Metal

Semi.

Metal

SurfaceHetero-Interface

Composition

Zhang lab

Nano Letters 2009;Nature 2010;Science 2010;Adv. Mater. 2014;Angew. Chem. Int. Ed., 2015;Nano Res. 2015.

Nanoscale 2013;NPG Asia Mater., 2015;Adv. Mater. 2015;Nano Res. 2015;Nano Lett. 2015;RSC Adv. 2014;CrystEngComm, 2014.

Nanophotonics

Photocatalysis

Photovoltaic

Luminescence

Electronic

Photothermal

Co@CdSeAu@CdS or Au@ZnSAu@CdS or Au@ZnS Au@PbS

Wang JF, Angew. Chem. Int. Ed. 2009; Klimov J, J. Am. Chem. Soc. 2005; Talapin D, J. Am. Chem. Soc. 2008. Cozzoli PD, Nano Today, 2010;

Wang X., NPG Asia Mater., 2015.

Large lattice mismatch: failure of hetero-epitaxial growth

Volmer- Weber (VW)

Large Lattice Mismatch

J. Zhang, Y. Tang, L. Weng & M. Ouyang, Nano Lett. 2009, 9, 4061.

Intermediate-Phase Assisted Phase Exchange and Reaction

Au@Ag core/shell hetero-epitaxial growth （ FM Mode)

Independent full control of core and shell:

2.8nm Au core 4.5nm Au core

Wavelength (nm)300 400 500 700600

Ext

inct

ion

(a.

u.)

Plain Au Core

1 monolayer Ag Shell

2 monolayers Ag Shell

3 monolayers Ag Shell

4 monolayers Ag Shell

5 monolayers Ag Shell

Model systems to investigate nanoscale optics-Plasmonics:

Surface micro/nanostructures evolution of Au-Ag alloy nanoplates:

300 600 900 1200 15000.0

0.2

0.4

0.6

0.8

1.0

1.2

L5L4L3L2L1

Ext

inct

ion(a

.u.)

Wavelength(nm)

L0 L1 L2 L3 L4 L5

L0

A

500 600 700 800 900 1000 1100 1200 13000

5

10

15

20

25

30

Ext

inct

ion E

ffici

ency

Wavelength (nm)

Ag nanoplate Au-Ag nanoplate Au-Ag nanoring

B

FEM simulation

0 100 200 300 400 500 6000

10

20

30

40

50

60Au-Ag alloy nanoplates

T(C

)

Time(s)

50 ppm 25 ppm 10 ppm 0 ppm

Photothermal conversion efficiency: 78.5%

H. M. Qian, J. T. Zhang*, Nano Res. 2015, accepted.

Nonepitaxial growth of metal@semi. nanostructures with large lattice mismatch

shell

amorphousXAg

base

SoftX

shell

metalAg 22

nxnx

n AgnXMMXnAg /3232

2 )PR(2)PR(2

J. Zhang, Y. Tang, K. Lee & M. Ouyang, Science 2010, 327, 1634-1638.J. Zhang, Y. Tang, K. Lee & M. Ouyang, Science 2010, 327, 1634-1638.

Step1 Step2 Step3

Controllable soft acid and base reaction:

J. Gui, J. Zhang*, et al. Angew. Chem. Int. Ed., 2015.

Independent control of core and shell:

Resonant or off-resonant Plasmon-exciton interactions tailoring

J. Zhang, Y. Tang, K. Lee & M. Ouyang, Nature 2010, 466, 91.

Enhanced Optical

Stark Effect (OSE)

50nm

Light–matter–spin interactions based on Plasmon-exciton coupling

50nm

Time-Resolved Faraday Rotation （ TRFR）Time-Resolved Faraday Rotation （ TRFR）

Plasmon enhanced solar energy conversion

Linic S, Nature Mater. 2011.Wang JF, Adv. Mater. 2014.

Cavity free or not？ Direct contact: interface control? Plasmon metal’s shape and size? Shape, size and doping of semi.

shell?

Cavity free or not？ Direct contact: interface control? Plasmon metal’s shape and size? Shape, size and doping of semi.

shell?

I. Plasmon enhanced electron/hole separation

II. Schottky contact

I. Plasmon enhanced electron/hole separation

II. Schottky contact

Two-step crystallizationTwo-step crystallization

Interface strain controlInterface strain control

Shape evolutionShape evolution

Au@CdSAu@CdSe Au@CdTe

From core/shell to heterodimer

Q. Zhao, J. Zhang*, et al. Adv. Mater. 2014, 26, 1387.

400 450 500 550 600 650 700 750 8000.00

0.25

0.50

0.75

1.00

1.25

1.50

Absorp

tion (a.u

.)

Wavelength (nm)

A

14

Plasmon-exciton coupling induced photocatalytic hydrogen evolution

The following by other groups

M. Zamkov*, Enhanced Lifetime of Excitons in Nonepitaxial Au/CdS Core/Shell Nanocrystals,

ACS Nano 2014, 352.

Suppression of exciton and plasmon featuresSuppression of exciton and plasmon features

M. Zamkov (Bowling Green State Uni. ） group：

Lower defect density and plamon enhanced lifetime of excitonsLower defect density and plamon enhanced lifetime of excitons

E-field enhancement of Plasmonic metal

Dependence of Kmax on the nanoparticle radius and the refractive index

field enhancement factor K = |E| ⁄ |E0|

Ponyavina, A. Journal of Applied Spectroscopy, 2008, 75, 832.

Qds: getting attached to nanosheets by OA and cation exchange with Ag doping control

Better interface contact induced improved electronic properties

H. Qian, J. Zhang*, etc. NPG Asia Mater. 2015.

-2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

Cu

rren

t (

A)

Voltage (V)

L/L0=1

L/L0=0.9

L/L0=0.82

L/L0=0.74

-2 -1 0 1 25

6

7

8

9

10

11

12

13

R/R

(0) (

%)

H (T)

2k 5K 10K 20K 30K 40K 50K 100K 150K

D

Research Summary （ NPG Asia Mater. ）

… Chinese scientists have developed an improved strategy for incorporating ultrabright Qds into flexible displays and solar cells. To overcome this problem, Jia-tao Zhang from Beijing Institute of Technology and colleagues…

Acknowledgements： Excellent Young Scientist Foundation of NSFC

21322105; NSFC 51372025, 91323301, 91123001; Beijing Gov. Key Laboratory Funding (BZ0351).Collaborates: Prof. Yadong Li (Tsinghua, China) Prof. Lin Gu (IP, CAS, China) Prof. Lei Jiang (TIPC, CAS, China) Prof. George Zhao (UQ, Australia) Prof. Qikun Xue (Tsinghua, China) Prof. Shouguo Wang (IP, CAS, China) Prof. Min Ouyang (UMCP, USA) Prof. Wei Zhang (IAPCM, China)

Prof. Chen Wang (NCNST, China) Prof. Weichang Hao (BUAA, China) Prof. Guozhen Shen (IS, CAS, China) Prof. Xiaowei Li (BIT, China) Prof. Dieter Fenske (KIT, Germany) Dr. Yuan Yao (IP, CAS, China) Prof. Shixue Dou (ISEM-UW, Australia) Prof. Lan Jiang (BIT, China)

Acknowledgements：

TTHANKSHANKS FORFOR YYOUROUR AATTENTIONTTENTION!!