Metal-Semiconductor Hetero- Nanocrystals and Their Optoelectronic Properties Research Jiatao Zhang 张张张张 () Beijing Institute of Technology 张张张张张张 2015.10.13
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!!