2023Dec ASU Wang NETR Group Research Focus and Facility Overview.pptx

1. ASU Nano-Engineered Thermal Radiation Group
Overview on Research Focuses and Lab Facility
- Efficient Energy Harvesting, Power Conversion and Radiative Thermal Control
with Thermophotonic Absorption and Emission
Dec 1, 2023
Liping Wang, Ph.D.
Associate Professor in Mechanical and Aerospace Engineering
School for Engineering of Matter, Transport & Energy
Arizona State University, Tempe, AZ
http://faculty.engineering.asu.edu/lpwang
Email: liping.wang@asu.edu

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Nano-Engineered Thermal Radiation Group
Electromagnetic Waves
https://en.wikipedia.org/wiki/Radiation_properties
Thermal Radiation

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Nano-Engineered Thermal Radiation Group
>95% solar absorption,
<5% re-emission loss
Temperature >400C
Solar-thermophotovoltaic (TPV)
High theoretical efficiency (85.4%); reliable;
recover waste heat from various sources
Optimal design of selective TPV emitter;
Enhancement through near-field radiation;
Prototype development.
Solution: Spectral control of thermal radiation
with nano-engineered materials (meta-materials)!
Application Driven
Solar-thermal
Advantages:
Low cost, large-area
implementation
Challenges:
Solar-photovoltaic (PV)
Low cost
flexible
Low efficiency;
Light Trapping to enhance
light absorption
Next-generation
thin-film solar cells
Basic Research
Background and Motivation

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Nano-Engineered Thermal Radiation Group
Radiative thermal control
Building Cooling Space Cooling
Challenge: dynamic control of surface emissivity/absorptivity
Background and Motivation
Microelectronics Cooling

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Nano-Engineered Thermal Radiation Group
SCIENCE AND ENGINEERING
(BASIC RESEARCH)
• Selective optical metamaterial
absorbers/emitters
• Extraordinary optical transmission
• Switchable and tunable infrared metamaterial
absorbers/emitters
• Near-field radiative transport between
metamaterials
• Modulation of near-field thermal radiation
with tunable materials
• Opto-thermal multiphysics on coupled energy
transport phenomena at nanoscale
• Advanced spectroscopy from cryogenic to high
temperatures at different length scale
• in-situ optical characterization coupled with
multiphysics
• Novel thermal metrology at different length
scales from millimeter to nanometer
(diffraction-limited optics and near-field
optics)
Research Focuses
GRAND CHALLENGES
(APPLICATION DRIVEN)
• Solar thermal, solar photovoltaic, and solar
thermophotovoltaic energy conversion and
harvesting
• Selective filters/polarizers
• Active control of thermal radiation for
optical sensing, infrared detectors, thermal
sources, space and radiative cooling
• Near-field heat transfer enhancement for
imaging, manufacturing, energy conversion
• Radiation-based thermal
control/management with vacuum thermal
rectifier, thermal switch, thermal transistor
• Plasmonics-induced local heating for data
storage, manufacturing, thermal storage

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Nano-Engineered Thermal Radiation Group
Research Focuses
Fundamental
Understanding
Fabrication &
Characterization
Modeling &
Optimization
Testing &
Experimentation
• Nanoscale heat transfer
• Electromagnetic waves
• Metamaterials and plasmonics
• Solar cell and photovoltaic
• Thermal rectification and transistor
• Multiphysics energy transport at nanoscale
• Modeling techniques such as FDTD,
RCWA, thin-film optics, MD, etc
• Fluctuational electrodynamics for near-
field radiative transfer
• Parametric and material optimization
• Microfab in clean room such as thin film
deposition, etching, photolithography, etc
• Nanofab such as EBL, nanoimprinting,
laser interference lithography
• Sample characterization such as AFM,
SEM, spectroscopy, etc
• Cryo-to-high temp. spectroscopy
• Solar testing
• Radiative cooling test
• NFR platform
• Customized AFM
• Laser scanning temp. mapping
• Photoluminescence

7. Nano-Engineered Thermal Radiation Group
#1 Selective absorption/emission with spectral control
2021 ES Mater. Manufact.
2021 iScience 2015 SOLMAT
Selective broadband
metamaterial solar absorber
Si-cored tungsten nanowire
selective solar absorber
Selective colored
metamaterial absorber

8. Nano-Engineered Thermal Radiation Group
#2 Thermophotonic power conversion
Solar TPV Designs Ultrathin PV/TPV Cell Design
2019 Solar Energy
0 20 40 60 80 100
200
400
600
800
1000
1200
1400
1600
Ideal absorber/emitter
Metafilm absorber/emitter
Black absorber/emitter
Absorber
temperature
(K)
Concentration factor
0 20 40 60 80 100
0
5
10
15
20
Ideal absorber/emitter
Metafilm absorber/emitter
Black absorber/emitter
STPV
system
efficiency
(%)
Concentration factor
2018 JPE
• Electrical modeling confirms non-radiative recombination
significantly reduced due to nm thickness;
• MoOx used as hole-selective layer for charge collection
2021 JQSRT 2014 AIP
2016 IJHMT

9. Nano-Engineered Thermal Radiation Group
#3 Tunable thermal emission
Electrically gated SiC
metasurface coherent emitter
2017 APL
Switchable
VO2 metamaterial
2019 Mater. Today Energy
Tunable
VO2 metasurface
2020 ACS Photon.
2019 ACS ANM

10. Nano-Engineered Thermal Radiation Group
#4 Radiative cooling / Dynamic thermal control
Bulk LiF radiative cooler
2020 SOLMAT
Variable-emittance VO2 metafilm
2020 SOLMAT 2021 ATE
2019 TSF
VO2 film growth VO2 metafilm fab Cryothermal test

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#5 Near-field thermal radiation
x6 blackbody flux from Al films
at 200 nm gap
x11 blackbody flux from
HDSi at 200nm gap
NFR Device Experiments
2020 JAP 2020 ACS Photon
NFR Device Designs
2014 JHT 2015 IJHMT
2017 JHT
Thermophotovoltaic (TPV):
Thermophototronic
switch/diode/transistor:
2019 JQSRT
2013 APL
2015 JQSRT 2017 JQSRT
2013 NMTE

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Nano-Engineered Thermal Radiation Group
Lab Facility on Optical Characterizations
Microscale Optical Reflectance/Transmittance (MORT)
Spectrometer +
Scanning Laser Thermoreflectance Microscope
Cryogenic-to-high-temperature Full-capability Spectrometry Platform (vis-MIR,
R/T/A, 77K-800K)
High-Temperature Emissometer
(spectral-directional emissivity, 500K-1300K)
Fourier-transform Spectrometer and Infrared
Microscope (vis-NIR-MIR)
Tunable Light Source for EQE and IS
measurements (UV-vis-NIR)

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Nano-Engineered Thermal Radiation Group
Lab Facility on Thermophotonic Energy Conversion
Thermophotovoltalic (TPV) or Vacuum Thermal Test
Solar Thermal/TPV Test with Variable Concentrated Solar Irradiation up to 60 Suns
Vacuum TPV Setup
Solar thermal/TPV Setup

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Nano-Engineered Thermal Radiation Group
Lab Facility on Radiative Thermal Control
Lab-scale Cryothermal Test for
tunable radiative heat control
with various thermal background
Outdoor Radiative Sky Cooling Test for sub-ambient temperature
Outdoor Radiative Vacuum Test for 24-hr power generation

15. Nano-Engineered Thermal Radiation Group
Lab Facility on Super-Planckian Near-field Radiation
Plate-Plate tunable NFR devices
graphene, VO2, etc
d > 100 nm
Tip-surface NFR
2D materials
d ~ nm
Sphere-plate NFR
metasurfaces, 2D materials
d > 30 nm
15
HV STM/AFM
NFR Tip
NFR Plate

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More research interests to explore/discover
Collaborations to seek
Expertise/facility to offer
• Thermophototronics (radiative thermal diode, transistor, memory, switch, etc)
• Non-reciprocal thermal radiation with Weyl semimetals, TIs, 2D materials, …
• Near-field TPV conversion with single and tandem cells
• Thermoradiative conversion (far and near fields)
• Photoluminescent cooling with near-field radiation
• Tunable near field radiation with 2D materials, TIs, etc
• ……..
• Talented and self-motivated students to work with
• Government agencies for supporting and sponsoring
• Materials experts to provide semiconductors, 2D, etc
• Device experts to fabricate designed devices
• Physicists to discover new physical mechanisms
• Industrial partners for prototyping and commercialization
• Optical/thermal modeling and design
• In-situ optical / thermal characterizations
• Thermophotonic devices and tunable radiative thermal control
• mm and nm scale temperature mapping
• Near-field charge/photon transport
To achieve bigger impacts
2015 NMTE

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Nano-Engineered Thermal Radiation Group
People that make things happen
• Team Players: (full list)
o Postdocs: Drs. Yue Yang (2017), Linshuang Long (2020), Qing Ni (2020), Ken Araki
o PhD students: Dr. Yue Yang (2016 FSE Dean’s Dissertation Award), Dr. Hao Wang (2016 SEMTE Best
Dissertation Award), Dr. Jui-Yung Chang (2017 MAE Best Dissertation Award), Dr. Hassan Alshehri (2018), Dr.
Payam Sabbaghi (2019), Dr. Sydney Taylor (2016 NASA NSTRF Fellow & 2020 FSE Dean’s Dissertation Award),
Dr. Raja Ramesh (2022), Ms. Xiaoyan Ying, Mr. Vishwa Krishna Rajan
o MS thesis students: Joseph Migliorini (2012), Mirza Opadija (2014), Hassan Alshehri (2014), Suhas Harish
(2015), Akshat Nair (2015), Ms. Hang Su (2016), Satish Sundarrajan (2016), Ramteja Kondakindi (2019), Ms.
Chuyun Guan (2019), Joseph Niko Vlastos (2020), Avinash Singh Nayal (2020), Jeremy Chao (2022), Vishwa
Krishna Rajan (2022), Antonio Trujillo (2022)
o UG students: 25+ Sun Devils

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Nano-Engineered Thermal Radiation Group
We are recruiting …..
If you are
• highly motivated, self driven, persistent and of good communication skills
• eager to learn fundamentals in understanding radiative thermal processes
• passionate about renewable energy conversion and thermal control
• ready to take on challenges and tackle difficult problems
• educated with thermal background like thermodynamics and heat transfer
• skilled in at least one programming language like MATLAB or simulation software
• enjoying lab work, fabrication, design and testing
• ……
Please feel free to reach me for possible research opportunities…
liping.wang@asu.edu
http://faculty.engineering.asu.edu/lpwang

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Nano-Engineered Thermal Radiation Group
Google Scholar Profile