marks group research style AWS
MARKS GROUP RESEARCH STYLE
Highly Interdisciplinary Integrated Synthesis, Spectroscopy, Mechanism Organometallics, Catalysis, New Reactions & Ligands Hard and Soft Matter, Interfaces, Solar Energy, Molecular Electronics Collaborations with Physicists, Engineers, Industrial & National Lab Scientists (Visits, Internships) Spirit of Teamwork
MARKS GROUP RESEARCH PROGRAM [email protected] http://www.chem.northwestern.edu/~marks/index.html
Themes Unconventional Electronics Building Blocks for Hybrid Inorganic/Organic Circuitry
Molecular and Polymer Photovoltaics Materials for Organic Photovoltaics and Displays
Catalysis with Homogeneous and Surface Metal Electrophiles Catalytic Routes to New Materials
Organometallic Chemistry of f-Elements; Green Chemistry Thermochemical Strategies for New Catalytic Transformations
Pushing the Envelope
GOAL: FLEXIBLE ELECTRONIC CIRCUITRY RF ID tags, display backplanes, e-books, sensors, “smart” packaging, “smart” displays, photovoltaics, “internet of things”
Roll-to-roll mfg
Science Needed for: Versatile, Unconventional Materials n- and p-Type Semiconductors for CMOS Compatible High-k Gate Dielectrics Synergy of Soft Matter & Hard Matter Constituents NRC/National Academies, “The Flexible Electronics Opportunity” National Academies Press, 2014 MRS Bulletin, articles and references therein, February 2017, 42
Transistor Structure & Function VD VG
Output plot
semiconductor source charge carriers drain dielectric gate / substrate
OFF VG = 0
ON VG ≠ 0
NO CHARGE CARRIERS BETWEEN s AND d => ID = 0 CREATES CHARGE CHANNEL IN SEMICONDUCTOR LAYER => ID ≠ 0
Transfer plot
New Materials Must Optimize: Carrier mobility (µ) & Stability Current on/off ratio (Ion/Ioff) Threshold voltage (VT) LCD Display Backplanes use a-Si:H Subthreshold swing (SS) µ ~ 0.5 cm2/V∙s-1Ion/Ioff > 106 Dielectric capacitance (Ci) n-type only, poor current carrier
Lecture Outline
I. Challenges, Opportunities
II. New Organic Semiconductors Properties Tuning, Devices
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SANDs). Designer Dielectrics
source
Semiconductor
Dielectric
Gate
IV. Amorphous Oxides Transistors, Hybrid Devices, Heterojunctions
V. Conclusions, Acknowledgments
drain
Materials Design for n-Type Semiconductors Enablers of Organic CMOS
p-Type = Radical cation (h+) conduction through highest occupied MOs (HOMOs) n-Type = Radical anion (e-) conduction through lowest unoccupied MOs (LUMOs)
R
R Substituents Enhance solubility
X
Molecule Substituents Lower HOMO, LUMO energies for electron transport, environmental stability
X Flat architecture π-π stacking Extended π system to minimize Marcus reorganization energy
High-yield coupling chemistry
R
Polymer
Linker
R X X
n
Reviews: MRS Bulletin, 2010, 35, 1018; Accts. Chem. Res. 2011, 44,501; Chem. Rev. 2014, 114, 8943.
p- and n-Type Copolymers & Devices Electron rich
O
C12H25
OC2H5
S
Br Br
OC2H5
C12H25
n
Me3Sn Pd(PPh3)2Cl2
PBDT-TVOE (p-type)
O
2OD N
Electron poor O
OC2H5
Br
S
S H 5C 2O
C12H25
C12H25 S
Br
S
S
2OD N O
O
S
S H 5C 2O
SnMe3 Pd(PPh3)2Cl2
S
S
N O 2OD
H 5C 2O O
N
n
O
2OD
PNDI-TVOE (n-type)
Complementary inverters: inkjet printed p- and n-type copolymers BGTC
Au
B.
Au
p+-Si
TGBC Au PMMA Semiconductor Au Au Passivation
ISD (A)
SiO2
10-6 10-7 10-8
0.2
10
10-10
1.5
0.0 0 306090 VSG (V)
D. -6 10
(ISD)1/2 (A)1/2 x10-2
C. 10
0.4
-9
Glass
-4
0.6
10-5
Semiconductor
ISD (A)
10-7 1.0
10-5 0.5
0.10
-8
10
0.05
10-9 10-10
10-6 0 30 60 90 VSG (V)
0.0
(ISD)1/2 (A)1/2 x10-2
A.
10-11
0
30 VSG (V)
0.00 60
Facchetti, Marks et al. J. Am. Chem. Soc. 2015, 137, 10966
Inkjet-Printed Bithiophene-Imide-Based AirStable Complementary Polymer Inverters Gain ~ 40 at VDD = - 100V R O
O
N
S
S
n
n-type
R O
O
N
R
R S
S
S
S
S
S
n
R
R
p-type
Ceradrop X-Serie Materials printer Guo, Ortiz, Noh, Baeg, Facchetti, Marks, J. Am. Chem. Soc..2018, in press.
Remarkable n-Type Polymer Semiconductors Highly ordered microstructure → ultra-high electron mobility
X-ray diffraction shows very high crystallinity, close packing of the chains Very small bandgaps, absorption out to ~1000 nm Preliminary OPV efficiency = 4.1% ; photocurrent out to 1000 nm
Bronstein, Al-Hashimi, Marks, Chen, et al Chem. Mater., 2016, 28, 8366–8378
80% FF Moderate Bandgap D-A OPV Copolymers
Polymer
Mn (kDa) PDI
PTPD3T PBTI3T
40 31
2.5 2.9
λ max abs film λ onset abs E HOMO (nm) 582 628
film (nm) (eV) 681 -5.55 686 -5.58
E LUMO (eV) -3.73 -3.77
E gopt
(eV) 1.82 1.81
J-V
e-
EQE
Inverted Cell Structure
h+ µ h (SCLC)
Polymer
µ h (TFT) (cm2/Vs)
PTPD3T
5.87 × 10-2
1.2 × 10-3
0.786 (0.795)
PBTI3T
2.74 × 10-3
1.5 × 10-3
0.850 (0.859)
(cm2/Vs)
V oc (V)
J cs
FF (%)
PCE (%)
12.3 (12.5)
78.7 (79.6)
7.72 (7.95)
12.8 (12.9)
76.3 (77.8)
8.42 (8.76)
(mA/cm2)
Guo, Huang, Chang, Chen, Marks Nature Photonics, 2013; JACS, 2015 & 2017.
Lecture Outline
I. Introduction, Challenges, Opportunities
II. New n-Type Organics Rylenedimides
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SAND)
IV. Amorphous Oxides Transistors
V. Conclusions, Acknowledgments
source
drain
Semiconductor
Dielectric
Gate
Need for Better Gate Dielectric: SANDs Enhance
Organic & Inorganic Transistor Mobility; Reduce Voltage & Hysteresis n- and p-Type Organic Semiconductors Carbon Nanotubes, Graphene ZnO & In2O3 Nanowires GaAs, 2D MoS2 Oxide Thin Films Conventional & Nanomembrane Si Si Nanomembrane TFTs
ISD~ µVG Ci
H+ Radiation-Hard SAND TFTs
Active Matrix ZnO NW/SAND OLED Display
Materials module deployed on the International Space Station. Inset: SAND-based transistors fabricated by Northwestern scientists Chem. Rev., 2010; Accts. Chem. Res. 2014; ACS Appl. Mater. Interfaces, 2016; Accts. Chem. Res. 2016
Next-Generation SANDs Customized for Specific Function Type III SAND Non-Ambient Growth Hydrocarbon Solvents
V-SAND Zr-SAND & Hf-SAND VA-SAND Ambient Growth Vapor Growth Vapor Growth Alcohol Solvents Avoid Solvents Avoid Solvents Zr
Zr
Zr
O
O HO
ALD Al2O3
O
O
O
O
HO
N
N
N N
N N N+
N+
Br O
O P O O O
P
O
O
Zr
Zr
Zr
Zr
Br
O
O
ALD Al2O3 MRS Bulletin, 2010; J. Am. Chem. Soc., 2011; ACS Nano, 2012; Accts. Chem. Res. 2014; Chem. Mater., 2017
Zr, Hf-SAND Self-Assembled Nanodielectrics TEM Cross-section • Organic/inorganic hybrid multilayer • Solution processable under ambient • Controllable thickness, large-area uniformity, well-defined structure • High capacitance, superior insulating properties • 350° C thermal stability
Fabrication • Self-assemble phosphonic acid-based polarizable π-molecule • Spin coat ultra-thin ZrOx primer & interlayers
Capacitance characteristics
M-SAND-4 (4 layer) • Leakage: 10-7 A/cm2 @2 MV/cm • Ci: 465 nF/cm2 (Zr), 1 μF/cm2 (Hf) • k ≈ 11 (Zr), 20 (Hf) •Roughness(RMS): 12 at 4 molecules/nm2 coverage
Computed dielectric constant of saturated & polyacetylenes at varying coverages. ε > 7.0 (C > 3.0 μF/cm2) Heitzer, Marks, Ratner, ACS Nano 2014; JACS 2015; Accts. Chem. Res. 2016,
In press
Synergistic Effects with Tight Packing Dielectric constant increases with chain length
d = film thickness
Capacitance does not decline as 1/d for conjugated chains. Capacitance reaches higher values than a linear extrapolation (-------)
Chain Dielectric constant
66Å 2 per molecule 33Å 2 per molecule
18 16 14 12 10 8 6 4 2
16.5Å 2 per molecule
Film Thickness Increases
0
10
20
30
40
Length (Å) Van Dyck, Marks, Ratner, ACS Nano, 2017, in press
Design Challenge: High ε with Low Leakage In oxides, smaller band gap leads to higher ε, but also larger leakage current
κε εs=2.21
AC
Can dielectric constant be increased while leakage current is kept constant? Quantum Interference
εs=2.24
AQ
εs=4.52
DFT calculations of conductance
AQON
εs=4.72
AQOF
DFT calculations of conductance
Conductance in organic molecules reduced by orders of magnitude without compromising dielectric performance. Bergfield, J.P.; Heitzer, H.M.; Van Ratner, Dyck, C.; Marks, ACS Nano, 2015, 9, 6412–6418. Bergfield, Heitzer, Van Dyck, Marks, ACS Nano, T.J.; 2015,Ratner, in press.M.A.; DOI:10.1021/acsnano.5b02042. MRSEC
Lecture Outline
I. Introduction, Challenges, Opportunities
II. New n- and p-Type Organics Rylenedimides
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SAND) Unconventional Semiconductors
IV. Amorphous Oxides Transistors, new tools, heterojunctions
V. Conclusions, Acknowledgments
source
drain
Semiconductor
Dielectric
Gate
Transparent Electronics Could Use Oxide TFTs + Organics Flexible Transparent Displays Transparent Displays
Heads-up Displays Artefactgroup.com
Technology Motivation
Samsung Transparent OLED TV
Xconomy.com Sharp IGZO Displays
Amorphous Oxide Driving Electronics: In-Ga-Zn-O? Can We Hybridize with Organic Materials?
TRANSPARENT CONDUCTING OXIDE (TCO) ELECTRONIC STRUCTURE MODEL J. Goodenough
Energy
CB
np
Metal Cation Conduction Band • Lies above top of O-2pπ VB by ΔEgap ≥ 3.1eV
ns
• Low enough in energy to accept electrons εF
ED
• Itinerant electrons cannot be excited into higher band by light absorption
Dope to make conductive (e.g., Sn in In2O3)
Cation Requirements Usually Met by O2-: 2p6
VB
N(ε) (DOS)
• 5s CB of Cd2+, In3+, Sn4+ • Burstein-Moss increase in ΔEgap with doping
What are the Limitations and Implications of this Picture? Can We Use These for TFTs? Freeman, Medvedeva Zunger
PNAS 2002, JACS 2007, MRS Bulletin 2010, Nature Mater 2016
Attractions of Amorphous Oxide Semiconductors (AOSs) for High-Performance TFTs Disordered Crystal Structures
High Mobility, s-State Conduction Band Low Deposition, Processing Temperatures Very Smooth Surfaces, No Grain Boundaries Mechanical Flexibility Optical Transparency
Film XRD and Electron Diffraction
Properties Tunable between Insulating, Semiconducting, Highly Conducting by Doping
Bellingham, Hosono, Mason, Wager Yu, X.; Marks, T.J.; Facchetti, A. Nature Materials, 2016, 15, 383- 396. DOI:10.1038/nmat4599.
Amorphous Semiconductor Electronic Structure Silicon 3p 3s
sp3
σ*
CBM
Si 1
Conduction Band
Conduction Band
Eg VBM
Transparent Oxide O 2p
Amorphous
Si 2
sp3 σ
O2-
Crystalline
CBM
M2+ M ns
Eg VBM
Attractions of a-Transparent Oxide Semiconductors: – – – –
Comparable carrier mobility Low processing temperature Uniformity, smoothness Mechanical flexibility
T. Kamiya; H. Hosono, Int. J. Appl. Ceram. Technol., 2005, 2, 285.
Art Freeman, Julia Medvedeva
Schematic Electronic Structure Around the IGZO Band Gap
T. Kamiya and H. Hosono. “Oxide TFTs” Handbook of Visual Display Technology, pp 729-749, Springer-Verlag, Heidelberg, 2015.
Transparent a-Zn-In-Sn-O TFTs Grown by Pulsed Laser Deposition
Protective Layer
Transmittance ~75% (glass ~90%) TFT Performance: μ ~160 cm2/V·s on SAND (μ ~20 on SiO2) VG & VDS ~1.0 V VT ~0.2 V Ion:Ioff ~105 This Isn’t Solution Processing! SS ~0.13 V/decade Chang, Facchetti, Marks Advan. Mater. 2010; J. Am. Chem. Soc. 2010; Nature Mater. 2016.
Low Temperature Combustion Synthesis of a -Oxide Films Solution Precursors Product
Combustion Condensed Oxide Lattice
Conventionalll
µ (cm2/Vs)
Reaction Coordinate
101
TFT Performance (Si/SiO2 Substrates) Conventional (Sol-Gel) Combustion 101 101 In2O3
-1
10-1
-3
10-3
10 10
-5
10
-7
10
Al2O3 dielectric
200 300 400 Temp (oC)
-7
10
Exo
20
20
0 100
0 100
In2O3
75
200 300o 400 Temp ( C)
-5
10
IZO
75
50
50
25
25 200 400 600 Temp (oC)
10-3 ZTO
40
10
10-1
-5
10
Reaction Characterization Conventional (Sol-Gel) Combustion 60 30
IZO 200 300 400 Temp (oC)
200 400 600 Temp (oC) TCO Conductivity
Conductivity (S/cm)
Ignition
Mass (%) DTA (µV/mg)
Energy
Oxidizer + Organic Fuel
103
101
-1
10
ITO
200 300 400 500 o Temp ( C)
Kim, Fachetti, Kanatzidis, Marks Nature Materials 2011, 2016; JACS 2017, in press.
Result: Inkjet Printed, Combustion-Processed Flexible Amorphous In2O3 Transistors on Plastic Transistor Characterization
Printed a-In2O3
3.0
1E-5
1E-7 1E-8
VG =1.00V
2.0 IDS IG
IDS (µA)
500 µm
IDS & IG (A)
1E-6 VDS = 1V
1.0 0.80V
1E-9
Research Agenda • Materials Scope • Microstructure Evolution • Performance Limits, SAND
1E-10 -0.5 0.0 0.5 1.0 VG (V)
0.0
0.60V
0.0
0.5 1.0 VDS (V)
Plastic: μ = 8 cm2/V·s Ion:Ioff ~ 104 Glass: μ = 40 cm2/V·s Ion:Ioff ~105 a-Al2O3 Gate Dielectric SAND Also Works
Kim, Fachetti, Kanatzidis, Marks Nature Materials 2011,10, 382; JACS 2017, in press.
Inkjet-Printed Combustion a-IGZO on Hf-SAND Dramatic operating voltage reduction
SiO2 Dielectric μ ≈ 5 cm2/Vs High operating voltage
Hf-SAND Dielectric μMAX > 40 cm2/Vs All-solution processed 2× mobility vs. spin-coated combustion >> sol-gel. IGZO TFT performance approaches sputtered ones. IGZO/ZrOx dielectric Mobility >20 cm2/Vs at 2V operation
Mobility (cm2Vs-1)
IGZO/SiOx dielectric
Sol-gel Combustion-spin Sputter SCS
103 101 10-1
IGZO
10-3 10-5
NA NA 225 250 275 300 Temperature (oC)
IGZO Density by Positron Annihilation Spectroscopy & X-ray Reflectivity: 10-3
IGZO Defect Density by C-V;
Sputtered ≈ SCS >> Sol-gel Microsoft Surface 4 has sputtered IGZO TFTs driving display
IDS (A)
Sputtered ≈ SCS >> Sol-gel
SCS IGZO on ZrOx
10-5 10-7 VDS= 2 V
-9
10
-1
0 1 VGS (V)
2
Top Gated SAND/Oxide Transistors Combine SAND Dielectric + Combustion Processed IGZO Au
SAND
Fundamental Questions: • • •
Future:
IGZO
• ITO
ITO
Al
Is SAND adaptable to top gate TFTs? Can SAND be grown on combustion processed oxide? What are characteristics of this novel interface?
Al
•
Characterize microstructure, interfacial defect densities as a function of oxide and oxide surface preparation Computation of interface characteristics
SiO2
Initial results are: – µsat ~ 20 cm2V-1s-1 – Vth = 0.79 V – Log (On/Off) = 7.16
Current (A)
1E-6 1E-8 1E-10 1E-12 -1 Chang, Bedzyk, Dravid, Hersam, Marks
Drain Current Gate Current
0
1
2
Gate Voltage (V)
3 32
MRSEC
‘Invisible’ Flexible TFTs Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends PVP concentration 0 - 20 wt%
In2O3 + PVP
XRD
• • •
Optical transparency
Bending test for flexible TFTs
Polymer blend + metal oxide: new route to amorphous oxide thin films MO:polymer blend films realize ultra-flexible electronic devices High performance flexible transparent transistors in solution process Chang, Bedzyk, Dravid, Marks, Advan. Mater., 2015.
What About an Electron-Rich Polymer? H
n
PVA
PEI N
N
OH
NH2
N
N
H
n
e
e e
Huang, W.; Zeng, L.; Yu, X.; Guo, P.; Wang, B.; Ma, Q.; Chang, R.P.H.; Yu, J.; Bedzyk, M.; Marks, T.J.; Facchetti, A.; Advan. Funct. Mater. 2016, 26, 6179-6187. DOI: 10.1002/adfm.201602069
Doped Hybrid Combustion Materials. Electron-Rich PEI As Organic Oxide Dopant PEI Mobilities on Si/SiO2 Dielectric
Higher Mobilities, Lower Ion/Ioff Microstructure-Electronic Properties Relationships No PEI
Film characterized by XRD, DSC, TGA, FT-IR, TGA, FET, AFM, XPS, XAS, PDF
< 1%
• Good crystallinity ~70% • Extensive Oxygen vacancies
• Deceased crystallinity • PEI electrons fill raps
• High Ioff • Negative VT
• Reduced Ioff • Positively shifted VT • Minor increased mobility
crystalline In2O3
1% - 1.5%
> 1.5%
• Mostly amorphous • Deep traps filled • Some shallow traps filled
• Mainly amorphous • Deep traps cannot be filled
• Low Ioff • Optimal VT ~ 0 V • Enhanced mobility
• Low Ioff • Positive VT • Decreased mobility
amorphous In2O3
PEI
Huang, W.; Zeng, L.; Yu, X.; Guo, P.; Wang, B.; Ma, Q.; Chang, R.P.H.; Yu, J.; Bedzyk, M.; Marks, T.J.; Facchetti, A.; Advan. Funct. Mater. 2016, 26, 6179-6187. DOI: 10.1002/adfm.201602069
Combustion Synthesis of All-Oxide IGZO Transistors Conformal Coating IGZO VDS=3 V
TFT functional layers SCS growth using shadow masks -2 -1 0
1
VGS (V)
2
3
Wang, B.; Yu, X.; Guo, P.; Huang, W.; Zeng, L.; Zhou, N.; Chi, L.; Bedzyk, M.J.; Chang, R.P.H.; Marks, T.J.; Facchetti, A.; Advan. Electron. Mater. 2016, 2, 1500427. DOI: 10.1002/aelm.201500427.
All SCS TFTs
TEM/EDX
Transparency
W/L=1000/150 μm
Wang, B.; Yu, X.; Guo, P.; Huang, W.; Zeng, L.; Zhou, N.; Chi, L.; Bedzyk, M.J.; Chang, R.P.H.; Marks, T.J.; Facchetti, A.; Advan. Electron. Mater. 2016, 2, 1500427. DOI: 10.1002/aelm.201500427.
PEI-In2O3 Hybrid Films
Sustainable “Sweet” Combustion Synthesis of IGZO
Mobilities with Si/SiO2 Dielectric Much Higher than with AcAcH! HO
H HO
Combustion Synthesis Film characterized by XRD, DSC, TGA, FT-IR, TGA, FET, AFM, XPS, XAS, PDF
HO
O OH
HO O OH
OH
HO O OH
O
HO
OH HO OH
O OH
OH OH
OH
Sugar
IGZO precursors
Wang, B.; Zeng, L.; Huang, W.; Melkonyan, F.; Sheets, W.C.; Chi, L.; Bedzyk, M.J.; Marks, T.J.; Facchetti, A.; J. Amer. Chem. Soc., 2016, 138, 7067–7074. DOI: 10.1021/jacs.6b02309.
a-IGZO/p-SWCNT Heterojunctions Goal Fabricate heterojunctions from solution processed p- (SWCNTs) and n- (a-IGZO) type semiconductors over large areas
HfO2 or Hf-SAND
Standard photolith & etching fabricate p-SWCNT/a-IGZO p-n heterojunctions over large areas Geometry allows fabrication of adjacent (control) p- and n- type MOSFETs next to heterojunction Hersam, Lauhon, Marks, PNAS 2013, 110, 18080 ; NanoLett. 2015, 15, 416; Nature Materials, 2017, 16, 170.
a-IGZO/p-SWCNT Heterojunction Electrical Properties
Anti-Ambipolar !
Rectifying diode-like output tunable with gate voltage Anti-ambipolar transfer with two off-states and one on-state Implications for communications keying circuitry Hersam, Lauhon, Marks, PNAS 2013, 110, 18080; NanoLett. 2015, 15, 416; Nature Materials, 2017, 16, 170.
Truly Flexible, Manufacturable Printed Displays Prototype: Polyera/Flexterra “Wove” Electrophoretic Display(EPD) + Organic Transistors
CONCLUSIONS Goal: Low Temperature Fabrication of Printed, Flexible, Transparent, Unconventional Electronic Circuitry
Printable Materials for Air-Stable Organic CMOS Design Rules for Stable n-Type Molecules, Polymers
High Performance Gate Dielectrics Molecularly Engineered High-k SANDs for OFETs, IFETs Low Voltage, Low Hysteresis
Hybrid Organic-Inorganic Circuitry Organics + Inorganics: The Winner?
*Theory & Modeling Essential to Materials Design* Understand known materials, design new ones
Applicable to Soft Matter Photovoltaics
Acknowledgments Northwestern University Antonio Facchetti Mark Ratner Michael Wasielewski Mercouri Kanatzidis Mark Hersam Vinayak Dravid Mike Bedzyk Lincoln Lauhon Bob Chang Sara Dibenedetto Zhiming Wang Hakan Usta Deep Jariwala Choongik Kim Xinge Yu Jeremy Smith Rocio Ortiz Young-Guen Ha Lian Wang Jun Liu Myung-Han Yoon Brooks Jones Henry Heitzer Myung-Gil Kim Vinod Sangwan Li Zeng
Johns Hopkins U. Howard Katz U. Texas Austin Ananth Dodabalapur Northwestern U. John Rogers U. Missouri. Julia Medvedeva TAMU-Q Mo Al-Hashimi Cambridge University Hugo Bronstein AFRL Mike Durstock, Ben Leever U. Malago Rocio Ortiz Purdue U. David Janes, Peter Ye
Numerous Colleagues in Europe and Asia!
$ AFOSR, ONR, NSF-MRSEC, NASA, DARPA,
Many Thanks!
a- ZITO/Arylite Anode OPV Bending Tests Sheet Resistance
OPV PCE
OPVs
OPV J-V
Chang, Marks, Advan. Mater. 2014
ITO Replacement: Flexible Amorphous-ZITO Electrodes on AryLite Polyester (> Zr-SAND? X-ray reflectivity reveals well-ordered nanostructures e-density
• X-ray fluorescence assay of Hf-SAND composition & coverage. • Denser PAE surface coverage on HfO2 enhances capacitance (1.1 μF/cm2) PAE Bedzyk, Hersam, Marks JACS 2013
Consequences of 1T→ 4T Catenation in TPD and BTI Photovoltaic Copolymers C12H25 S
n
S O
S S
O
O
N
N
S O
N
S
S S
O
C12H25
C12H25 S
S
n
O C8H17
S
S
S
S
n
S
S
n
C8H17
PTPD3T
C12H25 S
S O
O
N
C8H17
N
O
O
N
C8H17
PBTI1T
O C 2H 5 C 4H 9
S
S
C12H25
O
N
C6H13 C8H17
PTPD3T''
PTPD4T
S
n
S
S
S
S
S
n
S
S
S
S S
N
O C6H13 C8H17
O
PBTI3T
N
O C6H13 C8H17
O
PBTI3T'
N
O
O C6H13 C8H17
PBTI3T''
n C12H25
C12H25 C12H25 O
PBTI2T
O
n
S
C12H25
C12H25 O
C12H25 C12H25
C8H17
PTPD3T'
S
S
C6H13
S
S
S
n
S
C12H25 C12H25 S
n
S
S
C6H13
S
S
S
C12H25
O
N
C6H13
PTPD2T
n
C12H25 C12H25
C12H25 S
C8H17
C8H17
S
n C12H25
O
PTPD1T
S
S
C6H13
C6H13
S
C12H25
S
N
O C6H13 C8H17
PBTI4T
1T→ 4T OPV Trends for TPD & BTI Series • • • •
Conjugation length saturates at ~ 3T; HOMOs continue to rise TPDs: computed most planar; XRD/TEM: more crystalline, domain-pure PC71BM blends TPDs: higher mobilities & Jsc; FF, Jsc, PCE maximize at 3T PCE sensitive to alkyl substituent positioning. PTPD3T’, PTPD3T’’, PBTI3T’ & PBTI3T’’ have lower PCEs than PTPD3T & PBTI3T
Higher OPV Performance
Zhou, N.; Guo, X.; Ortiz, R.P.; Harschneck, T.; Manley, E.F.; Lou, S.J.; Hartnett, P.E.; Yu, X.; Horowitz, N.E.; Burrezo, P.M.; Aldrich, T.J.; Lopez Navarrette, J.T.; Wasielewski, M.; Chen, L.X.; Chang, R.P.H.; Facchetti, A.; Marks, T.J.; J.Am.Chem. Soc. 2015, 137, 12565.
Wafer-Scale SAND for Graphene Electronics Bottom contact graphene field-effect transistors (G-FETs) on 4 layers of Hf-SAND on 3” wafers Graphene grown by chemical vapor deposition, transferred on SAND
Optical micrographs of G-FETs on Hf-SAND-4L
Low operating voltage (±2 V) and negligible hysteresis on Hf-SAND in vacuum FET = 4,500 cm2/Vs (2x higher than on Si/SiO2) (limited by quality of CVD graphene, not dielectric) Current saturation with intrinsic gain > 1 Sangwan, Hersam, Marks, APL, 2014; ACS Appl. Mater. Interfaces, 2016, in press
TFT: AryLite/a-ZITO/Al2O3 /In2O3:PVP/ a-ZITO 10-3
Neat In2O3
IDS (A)
12 9
IDS1/2 (µA1/2)
10-5
Original r=15 mm r=13 mm r=10 mm
6 -7
10
10-9 -4
10
3 -1 0 1 2 3 -1 0 1 2 3 VGS (V) VGS (V) 5 % PVP
IDS (A)
8
4 -8
10
10-10
-1 0 1 2 3 -1 0 1 2 3 VGS (V) VGS (V)
Compare to neat In2O3 TFTs fabricated & measured under same conditions
6
IDS1/2 (µA1/2)
10-6
Original r=15 mm r=13 mm r=10 mm
0
Bending radius measurements:
2
SEM: neat In2O3 & In2O3:5%PVP films after bending at r = 10 mm
0
•
Neat In2O3 films show cracks
•
In2O3:5%PVP films don’t show cracks
In2O3
Bending radius
In2O3: 5% PVP
Bending times
Chang, Bedzyk, Dravid, Marks, Advan. Mater., 2015, DOI:10.1002/adma.201405400
Highly Interdisciplinary Integrated Synthesis, Spectroscopy, Mechanism Organometallics, Catalysis, New Reactions & Ligands Hard and Soft Matter, Interfaces, Solar Energy, Molecular Electronics Collaborations with Physicists, Engineers, Industrial & National Lab Scientists (Visits, Internships) Spirit of Teamwork
MARKS GROUP RESEARCH PROGRAM [email protected] http://www.chem.northwestern.edu/~marks/index.html
Themes Unconventional Electronics Building Blocks for Hybrid Inorganic/Organic Circuitry
Molecular and Polymer Photovoltaics Materials for Organic Photovoltaics and Displays
Catalysis with Homogeneous and Surface Metal Electrophiles Catalytic Routes to New Materials
Organometallic Chemistry of f-Elements; Green Chemistry Thermochemical Strategies for New Catalytic Transformations
Pushing the Envelope
GOAL: FLEXIBLE ELECTRONIC CIRCUITRY RF ID tags, display backplanes, e-books, sensors, “smart” packaging, “smart” displays, photovoltaics, “internet of things”
Roll-to-roll mfg
Science Needed for: Versatile, Unconventional Materials n- and p-Type Semiconductors for CMOS Compatible High-k Gate Dielectrics Synergy of Soft Matter & Hard Matter Constituents NRC/National Academies, “The Flexible Electronics Opportunity” National Academies Press, 2014 MRS Bulletin, articles and references therein, February 2017, 42
Transistor Structure & Function VD VG
Output plot
semiconductor source charge carriers drain dielectric gate / substrate
OFF VG = 0
ON VG ≠ 0
NO CHARGE CARRIERS BETWEEN s AND d => ID = 0 CREATES CHARGE CHANNEL IN SEMICONDUCTOR LAYER => ID ≠ 0
Transfer plot
New Materials Must Optimize: Carrier mobility (µ) & Stability Current on/off ratio (Ion/Ioff) Threshold voltage (VT) LCD Display Backplanes use a-Si:H Subthreshold swing (SS) µ ~ 0.5 cm2/V∙s-1Ion/Ioff > 106 Dielectric capacitance (Ci) n-type only, poor current carrier
Lecture Outline
I. Challenges, Opportunities
II. New Organic Semiconductors Properties Tuning, Devices
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SANDs). Designer Dielectrics
source
Semiconductor
Dielectric
Gate
IV. Amorphous Oxides Transistors, Hybrid Devices, Heterojunctions
V. Conclusions, Acknowledgments
drain
Materials Design for n-Type Semiconductors Enablers of Organic CMOS
p-Type = Radical cation (h+) conduction through highest occupied MOs (HOMOs) n-Type = Radical anion (e-) conduction through lowest unoccupied MOs (LUMOs)
R
R Substituents Enhance solubility
X
Molecule Substituents Lower HOMO, LUMO energies for electron transport, environmental stability
X Flat architecture π-π stacking Extended π system to minimize Marcus reorganization energy
High-yield coupling chemistry
R
Polymer
Linker
R X X
n
Reviews: MRS Bulletin, 2010, 35, 1018; Accts. Chem. Res. 2011, 44,501; Chem. Rev. 2014, 114, 8943.
p- and n-Type Copolymers & Devices Electron rich
O
C12H25
OC2H5
S
Br Br
OC2H5
C12H25
n
Me3Sn Pd(PPh3)2Cl2
PBDT-TVOE (p-type)
O
2OD N
Electron poor O
OC2H5
Br
S
S H 5C 2O
C12H25
C12H25 S
Br
S
S
2OD N O
O
S
S H 5C 2O
SnMe3 Pd(PPh3)2Cl2
S
S
N O 2OD
H 5C 2O O
N
n
O
2OD
PNDI-TVOE (n-type)
Complementary inverters: inkjet printed p- and n-type copolymers BGTC
Au
B.
Au
p+-Si
TGBC Au PMMA Semiconductor Au Au Passivation
ISD (A)
SiO2
10-6 10-7 10-8
0.2
10
10-10
1.5
0.0 0 306090 VSG (V)
D. -6 10
(ISD)1/2 (A)1/2 x10-2
C. 10
0.4
-9
Glass
-4
0.6
10-5
Semiconductor
ISD (A)
10-7 1.0
10-5 0.5
0.10
-8
10
0.05
10-9 10-10
10-6 0 30 60 90 VSG (V)
0.0
(ISD)1/2 (A)1/2 x10-2
A.
10-11
0
30 VSG (V)
0.00 60
Facchetti, Marks et al. J. Am. Chem. Soc. 2015, 137, 10966
Inkjet-Printed Bithiophene-Imide-Based AirStable Complementary Polymer Inverters Gain ~ 40 at VDD = - 100V R O
O
N
S
S
n
n-type
R O
O
N
R
R S
S
S
S
S
S
n
R
R
p-type
Ceradrop X-Serie Materials printer Guo, Ortiz, Noh, Baeg, Facchetti, Marks, J. Am. Chem. Soc..2018, in press.
Remarkable n-Type Polymer Semiconductors Highly ordered microstructure → ultra-high electron mobility
X-ray diffraction shows very high crystallinity, close packing of the chains Very small bandgaps, absorption out to ~1000 nm Preliminary OPV efficiency = 4.1% ; photocurrent out to 1000 nm
Bronstein, Al-Hashimi, Marks, Chen, et al Chem. Mater., 2016, 28, 8366–8378
80% FF Moderate Bandgap D-A OPV Copolymers
Polymer
Mn (kDa) PDI
PTPD3T PBTI3T
40 31
2.5 2.9
λ max abs film λ onset abs E HOMO (nm) 582 628
film (nm) (eV) 681 -5.55 686 -5.58
E LUMO (eV) -3.73 -3.77
E gopt
(eV) 1.82 1.81
J-V
e-
EQE
Inverted Cell Structure
h+ µ h (SCLC)
Polymer
µ h (TFT) (cm2/Vs)
PTPD3T
5.87 × 10-2
1.2 × 10-3
0.786 (0.795)
PBTI3T
2.74 × 10-3
1.5 × 10-3
0.850 (0.859)
(cm2/Vs)
V oc (V)
J cs
FF (%)
PCE (%)
12.3 (12.5)
78.7 (79.6)
7.72 (7.95)
12.8 (12.9)
76.3 (77.8)
8.42 (8.76)
(mA/cm2)
Guo, Huang, Chang, Chen, Marks Nature Photonics, 2013; JACS, 2015 & 2017.
Lecture Outline
I. Introduction, Challenges, Opportunities
II. New n-Type Organics Rylenedimides
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SAND)
IV. Amorphous Oxides Transistors
V. Conclusions, Acknowledgments
source
drain
Semiconductor
Dielectric
Gate
Need for Better Gate Dielectric: SANDs Enhance
Organic & Inorganic Transistor Mobility; Reduce Voltage & Hysteresis n- and p-Type Organic Semiconductors Carbon Nanotubes, Graphene ZnO & In2O3 Nanowires GaAs, 2D MoS2 Oxide Thin Films Conventional & Nanomembrane Si Si Nanomembrane TFTs
ISD~ µVG Ci
H+ Radiation-Hard SAND TFTs
Active Matrix ZnO NW/SAND OLED Display
Materials module deployed on the International Space Station. Inset: SAND-based transistors fabricated by Northwestern scientists Chem. Rev., 2010; Accts. Chem. Res. 2014; ACS Appl. Mater. Interfaces, 2016; Accts. Chem. Res. 2016
Next-Generation SANDs Customized for Specific Function Type III SAND Non-Ambient Growth Hydrocarbon Solvents
V-SAND Zr-SAND & Hf-SAND VA-SAND Ambient Growth Vapor Growth Vapor Growth Alcohol Solvents Avoid Solvents Avoid Solvents Zr
Zr
Zr
O
O HO
ALD Al2O3
O
O
O
O
HO
N
N
N N
N N N+
N+
Br O
O P O O O
P
O
O
Zr
Zr
Zr
Zr
Br
O
O
ALD Al2O3 MRS Bulletin, 2010; J. Am. Chem. Soc., 2011; ACS Nano, 2012; Accts. Chem. Res. 2014; Chem. Mater., 2017
Zr, Hf-SAND Self-Assembled Nanodielectrics TEM Cross-section • Organic/inorganic hybrid multilayer • Solution processable under ambient • Controllable thickness, large-area uniformity, well-defined structure • High capacitance, superior insulating properties • 350° C thermal stability
Fabrication • Self-assemble phosphonic acid-based polarizable π-molecule • Spin coat ultra-thin ZrOx primer & interlayers
Capacitance characteristics
M-SAND-4 (4 layer) • Leakage: 10-7 A/cm2 @2 MV/cm • Ci: 465 nF/cm2 (Zr), 1 μF/cm2 (Hf) • k ≈ 11 (Zr), 20 (Hf) •Roughness(RMS): 12 at 4 molecules/nm2 coverage
Computed dielectric constant of saturated & polyacetylenes at varying coverages. ε > 7.0 (C > 3.0 μF/cm2) Heitzer, Marks, Ratner, ACS Nano 2014; JACS 2015; Accts. Chem. Res. 2016,
In press
Synergistic Effects with Tight Packing Dielectric constant increases with chain length
d = film thickness
Capacitance does not decline as 1/d for conjugated chains. Capacitance reaches higher values than a linear extrapolation (-------)
Chain Dielectric constant
66Å 2 per molecule 33Å 2 per molecule
18 16 14 12 10 8 6 4 2
16.5Å 2 per molecule
Film Thickness Increases
0
10
20
30
40
Length (Å) Van Dyck, Marks, Ratner, ACS Nano, 2017, in press
Design Challenge: High ε with Low Leakage In oxides, smaller band gap leads to higher ε, but also larger leakage current
κε εs=2.21
AC
Can dielectric constant be increased while leakage current is kept constant? Quantum Interference
εs=2.24
AQ
εs=4.52
DFT calculations of conductance
AQON
εs=4.72
AQOF
DFT calculations of conductance
Conductance in organic molecules reduced by orders of magnitude without compromising dielectric performance. Bergfield, J.P.; Heitzer, H.M.; Van Ratner, Dyck, C.; Marks, ACS Nano, 2015, 9, 6412–6418. Bergfield, Heitzer, Van Dyck, Marks, ACS Nano, T.J.; 2015,Ratner, in press.M.A.; DOI:10.1021/acsnano.5b02042. MRSEC
Lecture Outline
I. Introduction, Challenges, Opportunities
II. New n- and p-Type Organics Rylenedimides
III. Nanoscopic Dielectrics Self-Assembled Nanodielectrics (SAND) Unconventional Semiconductors
IV. Amorphous Oxides Transistors, new tools, heterojunctions
V. Conclusions, Acknowledgments
source
drain
Semiconductor
Dielectric
Gate
Transparent Electronics Could Use Oxide TFTs + Organics Flexible Transparent Displays Transparent Displays
Heads-up Displays Artefactgroup.com
Technology Motivation
Samsung Transparent OLED TV
Xconomy.com Sharp IGZO Displays
Amorphous Oxide Driving Electronics: In-Ga-Zn-O? Can We Hybridize with Organic Materials?
TRANSPARENT CONDUCTING OXIDE (TCO) ELECTRONIC STRUCTURE MODEL J. Goodenough
Energy
CB
np
Metal Cation Conduction Band • Lies above top of O-2pπ VB by ΔEgap ≥ 3.1eV
ns
• Low enough in energy to accept electrons εF
ED
• Itinerant electrons cannot be excited into higher band by light absorption
Dope to make conductive (e.g., Sn in In2O3)
Cation Requirements Usually Met by O2-: 2p6
VB
N(ε) (DOS)
• 5s CB of Cd2+, In3+, Sn4+ • Burstein-Moss increase in ΔEgap with doping
What are the Limitations and Implications of this Picture? Can We Use These for TFTs? Freeman, Medvedeva Zunger
PNAS 2002, JACS 2007, MRS Bulletin 2010, Nature Mater 2016
Attractions of Amorphous Oxide Semiconductors (AOSs) for High-Performance TFTs Disordered Crystal Structures
High Mobility, s-State Conduction Band Low Deposition, Processing Temperatures Very Smooth Surfaces, No Grain Boundaries Mechanical Flexibility Optical Transparency
Film XRD and Electron Diffraction
Properties Tunable between Insulating, Semiconducting, Highly Conducting by Doping
Bellingham, Hosono, Mason, Wager Yu, X.; Marks, T.J.; Facchetti, A. Nature Materials, 2016, 15, 383- 396. DOI:10.1038/nmat4599.
Amorphous Semiconductor Electronic Structure Silicon 3p 3s
sp3
σ*
CBM
Si 1
Conduction Band
Conduction Band
Eg VBM
Transparent Oxide O 2p
Amorphous
Si 2
sp3 σ
O2-
Crystalline
CBM
M2+ M ns
Eg VBM
Attractions of a-Transparent Oxide Semiconductors: – – – –
Comparable carrier mobility Low processing temperature Uniformity, smoothness Mechanical flexibility
T. Kamiya; H. Hosono, Int. J. Appl. Ceram. Technol., 2005, 2, 285.
Art Freeman, Julia Medvedeva
Schematic Electronic Structure Around the IGZO Band Gap
T. Kamiya and H. Hosono. “Oxide TFTs” Handbook of Visual Display Technology, pp 729-749, Springer-Verlag, Heidelberg, 2015.
Transparent a-Zn-In-Sn-O TFTs Grown by Pulsed Laser Deposition
Protective Layer
Transmittance ~75% (glass ~90%) TFT Performance: μ ~160 cm2/V·s on SAND (μ ~20 on SiO2) VG & VDS ~1.0 V VT ~0.2 V Ion:Ioff ~105 This Isn’t Solution Processing! SS ~0.13 V/decade Chang, Facchetti, Marks Advan. Mater. 2010; J. Am. Chem. Soc. 2010; Nature Mater. 2016.
Low Temperature Combustion Synthesis of a -Oxide Films Solution Precursors Product
Combustion Condensed Oxide Lattice
Conventionalll
µ (cm2/Vs)
Reaction Coordinate
101
TFT Performance (Si/SiO2 Substrates) Conventional (Sol-Gel) Combustion 101 101 In2O3
-1
10-1
-3
10-3
10 10
-5
10
-7
10
Al2O3 dielectric
200 300 400 Temp (oC)
-7
10
Exo
20
20
0 100
0 100
In2O3
75
200 300o 400 Temp ( C)
-5
10
IZO
75
50
50
25
25 200 400 600 Temp (oC)
10-3 ZTO
40
10
10-1
-5
10
Reaction Characterization Conventional (Sol-Gel) Combustion 60 30
IZO 200 300 400 Temp (oC)
200 400 600 Temp (oC) TCO Conductivity
Conductivity (S/cm)
Ignition
Mass (%) DTA (µV/mg)
Energy
Oxidizer + Organic Fuel
103
101
-1
10
ITO
200 300 400 500 o Temp ( C)
Kim, Fachetti, Kanatzidis, Marks Nature Materials 2011, 2016; JACS 2017, in press.
Result: Inkjet Printed, Combustion-Processed Flexible Amorphous In2O3 Transistors on Plastic Transistor Characterization
Printed a-In2O3
3.0
1E-5
1E-7 1E-8
VG =1.00V
2.0 IDS IG
IDS (µA)
500 µm
IDS & IG (A)
1E-6 VDS = 1V
1.0 0.80V
1E-9
Research Agenda • Materials Scope • Microstructure Evolution • Performance Limits, SAND
1E-10 -0.5 0.0 0.5 1.0 VG (V)
0.0
0.60V
0.0
0.5 1.0 VDS (V)
Plastic: μ = 8 cm2/V·s Ion:Ioff ~ 104 Glass: μ = 40 cm2/V·s Ion:Ioff ~105 a-Al2O3 Gate Dielectric SAND Also Works
Kim, Fachetti, Kanatzidis, Marks Nature Materials 2011,10, 382; JACS 2017, in press.
Inkjet-Printed Combustion a-IGZO on Hf-SAND Dramatic operating voltage reduction
SiO2 Dielectric μ ≈ 5 cm2/Vs High operating voltage
Hf-SAND Dielectric μMAX > 40 cm2/Vs All-solution processed 2× mobility vs. spin-coated combustion >> sol-gel. IGZO TFT performance approaches sputtered ones. IGZO/ZrOx dielectric Mobility >20 cm2/Vs at 2V operation
Mobility (cm2Vs-1)
IGZO/SiOx dielectric
Sol-gel Combustion-spin Sputter SCS
103 101 10-1
IGZO
10-3 10-5
NA NA 225 250 275 300 Temperature (oC)
IGZO Density by Positron Annihilation Spectroscopy & X-ray Reflectivity: 10-3
IGZO Defect Density by C-V;
Sputtered ≈ SCS >> Sol-gel Microsoft Surface 4 has sputtered IGZO TFTs driving display
IDS (A)
Sputtered ≈ SCS >> Sol-gel
SCS IGZO on ZrOx
10-5 10-7 VDS= 2 V
-9
10
-1
0 1 VGS (V)
2
Top Gated SAND/Oxide Transistors Combine SAND Dielectric + Combustion Processed IGZO Au
SAND
Fundamental Questions: • • •
Future:
IGZO
• ITO
ITO
Al
Is SAND adaptable to top gate TFTs? Can SAND be grown on combustion processed oxide? What are characteristics of this novel interface?
Al
•
Characterize microstructure, interfacial defect densities as a function of oxide and oxide surface preparation Computation of interface characteristics
SiO2
Initial results are: – µsat ~ 20 cm2V-1s-1 – Vth = 0.79 V – Log (On/Off) = 7.16
Current (A)
1E-6 1E-8 1E-10 1E-12 -1 Chang, Bedzyk, Dravid, Hersam, Marks
Drain Current Gate Current
0
1
2
Gate Voltage (V)
3 32
MRSEC
‘Invisible’ Flexible TFTs Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends PVP concentration 0 - 20 wt%
In2O3 + PVP
XRD
• • •
Optical transparency
Bending test for flexible TFTs
Polymer blend + metal oxide: new route to amorphous oxide thin films MO:polymer blend films realize ultra-flexible electronic devices High performance flexible transparent transistors in solution process Chang, Bedzyk, Dravid, Marks, Advan. Mater., 2015.
What About an Electron-Rich Polymer? H
n
PVA
PEI N
N
OH
NH2
N
N
H
n
e
e e
Huang, W.; Zeng, L.; Yu, X.; Guo, P.; Wang, B.; Ma, Q.; Chang, R.P.H.; Yu, J.; Bedzyk, M.; Marks, T.J.; Facchetti, A.; Advan. Funct. Mater. 2016, 26, 6179-6187. DOI: 10.1002/adfm.201602069
Doped Hybrid Combustion Materials. Electron-Rich PEI As Organic Oxide Dopant PEI Mobilities on Si/SiO2 Dielectric
Higher Mobilities, Lower Ion/Ioff Microstructure-Electronic Properties Relationships No PEI
Film characterized by XRD, DSC, TGA, FT-IR, TGA, FET, AFM, XPS, XAS, PDF
< 1%
• Good crystallinity ~70% • Extensive Oxygen vacancies
• Deceased crystallinity • PEI electrons fill raps
• High Ioff • Negative VT
• Reduced Ioff • Positively shifted VT • Minor increased mobility
crystalline In2O3
1% - 1.5%
> 1.5%
• Mostly amorphous • Deep traps filled • Some shallow traps filled
• Mainly amorphous • Deep traps cannot be filled
• Low Ioff • Optimal VT ~ 0 V • Enhanced mobility
• Low Ioff • Positive VT • Decreased mobility
amorphous In2O3
PEI
Huang, W.; Zeng, L.; Yu, X.; Guo, P.; Wang, B.; Ma, Q.; Chang, R.P.H.; Yu, J.; Bedzyk, M.; Marks, T.J.; Facchetti, A.; Advan. Funct. Mater. 2016, 26, 6179-6187. DOI: 10.1002/adfm.201602069
Combustion Synthesis of All-Oxide IGZO Transistors Conformal Coating IGZO VDS=3 V
TFT functional layers SCS growth using shadow masks -2 -1 0
1
VGS (V)
2
3
Wang, B.; Yu, X.; Guo, P.; Huang, W.; Zeng, L.; Zhou, N.; Chi, L.; Bedzyk, M.J.; Chang, R.P.H.; Marks, T.J.; Facchetti, A.; Advan. Electron. Mater. 2016, 2, 1500427. DOI: 10.1002/aelm.201500427.
All SCS TFTs
TEM/EDX
Transparency
W/L=1000/150 μm
Wang, B.; Yu, X.; Guo, P.; Huang, W.; Zeng, L.; Zhou, N.; Chi, L.; Bedzyk, M.J.; Chang, R.P.H.; Marks, T.J.; Facchetti, A.; Advan. Electron. Mater. 2016, 2, 1500427. DOI: 10.1002/aelm.201500427.
PEI-In2O3 Hybrid Films
Sustainable “Sweet” Combustion Synthesis of IGZO
Mobilities with Si/SiO2 Dielectric Much Higher than with AcAcH! HO
H HO
Combustion Synthesis Film characterized by XRD, DSC, TGA, FT-IR, TGA, FET, AFM, XPS, XAS, PDF
HO
O OH
HO O OH
OH
HO O OH
O
HO
OH HO OH
O OH
OH OH
OH
Sugar
IGZO precursors
Wang, B.; Zeng, L.; Huang, W.; Melkonyan, F.; Sheets, W.C.; Chi, L.; Bedzyk, M.J.; Marks, T.J.; Facchetti, A.; J. Amer. Chem. Soc., 2016, 138, 7067–7074. DOI: 10.1021/jacs.6b02309.
a-IGZO/p-SWCNT Heterojunctions Goal Fabricate heterojunctions from solution processed p- (SWCNTs) and n- (a-IGZO) type semiconductors over large areas
HfO2 or Hf-SAND
Standard photolith & etching fabricate p-SWCNT/a-IGZO p-n heterojunctions over large areas Geometry allows fabrication of adjacent (control) p- and n- type MOSFETs next to heterojunction Hersam, Lauhon, Marks, PNAS 2013, 110, 18080 ; NanoLett. 2015, 15, 416; Nature Materials, 2017, 16, 170.
a-IGZO/p-SWCNT Heterojunction Electrical Properties
Anti-Ambipolar !
Rectifying diode-like output tunable with gate voltage Anti-ambipolar transfer with two off-states and one on-state Implications for communications keying circuitry Hersam, Lauhon, Marks, PNAS 2013, 110, 18080; NanoLett. 2015, 15, 416; Nature Materials, 2017, 16, 170.
Truly Flexible, Manufacturable Printed Displays Prototype: Polyera/Flexterra “Wove” Electrophoretic Display(EPD) + Organic Transistors
CONCLUSIONS Goal: Low Temperature Fabrication of Printed, Flexible, Transparent, Unconventional Electronic Circuitry
Printable Materials for Air-Stable Organic CMOS Design Rules for Stable n-Type Molecules, Polymers
High Performance Gate Dielectrics Molecularly Engineered High-k SANDs for OFETs, IFETs Low Voltage, Low Hysteresis
Hybrid Organic-Inorganic Circuitry Organics + Inorganics: The Winner?
*Theory & Modeling Essential to Materials Design* Understand known materials, design new ones
Applicable to Soft Matter Photovoltaics
Acknowledgments Northwestern University Antonio Facchetti Mark Ratner Michael Wasielewski Mercouri Kanatzidis Mark Hersam Vinayak Dravid Mike Bedzyk Lincoln Lauhon Bob Chang Sara Dibenedetto Zhiming Wang Hakan Usta Deep Jariwala Choongik Kim Xinge Yu Jeremy Smith Rocio Ortiz Young-Guen Ha Lian Wang Jun Liu Myung-Han Yoon Brooks Jones Henry Heitzer Myung-Gil Kim Vinod Sangwan Li Zeng
Johns Hopkins U. Howard Katz U. Texas Austin Ananth Dodabalapur Northwestern U. John Rogers U. Missouri. Julia Medvedeva TAMU-Q Mo Al-Hashimi Cambridge University Hugo Bronstein AFRL Mike Durstock, Ben Leever U. Malago Rocio Ortiz Purdue U. David Janes, Peter Ye
Numerous Colleagues in Europe and Asia!
$ AFOSR, ONR, NSF-MRSEC, NASA, DARPA,
Many Thanks!
a- ZITO/Arylite Anode OPV Bending Tests Sheet Resistance
OPV PCE
OPVs
OPV J-V
Chang, Marks, Advan. Mater. 2014
ITO Replacement: Flexible Amorphous-ZITO Electrodes on AryLite Polyester (> Zr-SAND? X-ray reflectivity reveals well-ordered nanostructures e-density
• X-ray fluorescence assay of Hf-SAND composition & coverage. • Denser PAE surface coverage on HfO2 enhances capacitance (1.1 μF/cm2) PAE Bedzyk, Hersam, Marks JACS 2013
Consequences of 1T→ 4T Catenation in TPD and BTI Photovoltaic Copolymers C12H25 S
n
S O
S S
O
O
N
N
S O
N
S
S S
O
C12H25
C12H25 S
S
n
O C8H17
S
S
S
S
n
S
S
n
C8H17
PTPD3T
C12H25 S
S O
O
N
C8H17
N
O
O
N
C8H17
PBTI1T
O C 2H 5 C 4H 9
S
S
C12H25
O
N
C6H13 C8H17
PTPD3T''
PTPD4T
S
n
S
S
S
S
S
n
S
S
S
S S
N
O C6H13 C8H17
O
PBTI3T
N
O C6H13 C8H17
O
PBTI3T'
N
O
O C6H13 C8H17
PBTI3T''
n C12H25
C12H25 C12H25 O
PBTI2T
O
n
S
C12H25
C12H25 O
C12H25 C12H25
C8H17
PTPD3T'
S
S
C6H13
S
S
S
n
S
C12H25 C12H25 S
n
S
S
C6H13
S
S
S
C12H25
O
N
C6H13
PTPD2T
n
C12H25 C12H25
C12H25 S
C8H17
C8H17
S
n C12H25
O
PTPD1T
S
S
C6H13
C6H13
S
C12H25
S
N
O C6H13 C8H17
PBTI4T
1T→ 4T OPV Trends for TPD & BTI Series • • • •
Conjugation length saturates at ~ 3T; HOMOs continue to rise TPDs: computed most planar; XRD/TEM: more crystalline, domain-pure PC71BM blends TPDs: higher mobilities & Jsc; FF, Jsc, PCE maximize at 3T PCE sensitive to alkyl substituent positioning. PTPD3T’, PTPD3T’’, PBTI3T’ & PBTI3T’’ have lower PCEs than PTPD3T & PBTI3T
Higher OPV Performance
Zhou, N.; Guo, X.; Ortiz, R.P.; Harschneck, T.; Manley, E.F.; Lou, S.J.; Hartnett, P.E.; Yu, X.; Horowitz, N.E.; Burrezo, P.M.; Aldrich, T.J.; Lopez Navarrette, J.T.; Wasielewski, M.; Chen, L.X.; Chang, R.P.H.; Facchetti, A.; Marks, T.J.; J.Am.Chem. Soc. 2015, 137, 12565.
Wafer-Scale SAND for Graphene Electronics Bottom contact graphene field-effect transistors (G-FETs) on 4 layers of Hf-SAND on 3” wafers Graphene grown by chemical vapor deposition, transferred on SAND
Optical micrographs of G-FETs on Hf-SAND-4L
Low operating voltage (±2 V) and negligible hysteresis on Hf-SAND in vacuum FET = 4,500 cm2/Vs (2x higher than on Si/SiO2) (limited by quality of CVD graphene, not dielectric) Current saturation with intrinsic gain > 1 Sangwan, Hersam, Marks, APL, 2014; ACS Appl. Mater. Interfaces, 2016, in press
TFT: AryLite/a-ZITO/Al2O3 /In2O3:PVP/ a-ZITO 10-3
Neat In2O3
IDS (A)
12 9
IDS1/2 (µA1/2)
10-5
Original r=15 mm r=13 mm r=10 mm
6 -7
10
10-9 -4
10
3 -1 0 1 2 3 -1 0 1 2 3 VGS (V) VGS (V) 5 % PVP
IDS (A)
8
4 -8
10
10-10
-1 0 1 2 3 -1 0 1 2 3 VGS (V) VGS (V)
Compare to neat In2O3 TFTs fabricated & measured under same conditions
6
IDS1/2 (µA1/2)
10-6
Original r=15 mm r=13 mm r=10 mm
0
Bending radius measurements:
2
SEM: neat In2O3 & In2O3:5%PVP films after bending at r = 10 mm
0
•
Neat In2O3 films show cracks
•
In2O3:5%PVP films don’t show cracks
In2O3
Bending radius
In2O3: 5% PVP
Bending times
Chang, Bedzyk, Dravid, Marks, Advan. Mater., 2015, DOI:10.1002/adma.201405400
