Powering Big Data and the IoT’s…

…a great challenge and an even greater

opportunity for materials efficiency using low cost

perovskite solar cells

Reinhold H. Dauskardt (dauskardt@stanford.edu)

…by 2020, it is expected

that more than 28 billion

IoT devices will be in

operation...

Prepare for a Connected World where Everything

Computes…

Internet of Content

(Distribution/Access)• Email

• Information

• Entertainment

Internet of Service

(Participation/Trade)• E-commerce

• Productivity tools

• Integrated chains

Internet of People

(Collaboration/Share)• Voice and video collaboration

• Social media and docs

• Web logs/boards

Internet of Things

(Integration/Control)• Indexing and tracking

• Control and connectivity

• Autonomous operations

https://www.hpe.com

• Smart devices create opportunities to gain faster insights by connecting the

unconnected

• New ways to - conduct material discovery and drive materials efficiency

- develop new business with greater insights

- learn about the environment and enable sustainability

- enable developing nations and their citizens

Energy Is A Big And Rapidly Growing Problem

For Big Data and the IoTs

• U.S. data centers use more than 90 billion kilowatt-hours of electricity a year,

requiring roughly 34 giant (500-megawatt) coal-powered plants.

• Global data centers used roughly 416 terawatts (4.16 x 1014 watts) (or about

3% of the total electricity) last year, nearly 40% more than the entire United

Kingdom.

• Consumption will double every four years…

Reported by Danilak, Forbes, Dec 2017.

• Billions of Machine-to-Machine devices in use today and an ever-increasing

number of connected devices using low-power, low-throughput networks.

• Billions of additional point-of-use devices, from personal electronics, smart

sensors for home and urban centers, traffic sensors and parking meters, and

even technologically connected ecosystems, …

Energy Is A Big And Rapidly Growing Problem

For Big Data and the IoTs

solar-powered

parking meters

generated

>$230,000 for

Los Angeles

sensors under forest

canopy for real-time

forest monitoring

(Perlis, northern most

state of Malaysia)

2016 IEEE Student Conf Res Dev

Energy Is A Big And Rapidly Growing Problem

For Big Data and the IoTs

2016 IEEE Student Conf Res Dev

• Comprehensive solution to the challenge of powering the IoT’s:

• design of ultra-low power embedded hardware platforms

• intelligent system-level power management

• make devices self-powered by harvesting energy from their operating

environment

local energy harvesting

is key, from

thermoelectric,

electrodynamic,

vibration and motion,

and from solar…

…but low cost is an

equally important

driver…

https://www.ossila.com/pages/perovskite-pv-materials

Metal Halide Perovskites – Next Generation Solar Cells• tunable bandgap 1.2 – 2.3 eV and excellent efficiency

• strong optical absorption (~1000x thinner than silicon) – much greater materials efficiency

• tolerance to defects and grain boundaries

• solution processable with scalable-manufacturing – make much cheaper

Challenge• Stability and reliability

…need new concepts

in solar module

processing and design

perovskites

so we can use longer

Sunshine is Plentiful and Inexhaustible

Perovskite Device Architectures Studied

PEDOT:PSS

ZnO

CH3NH3PbI3

ITO-Glass

Al

PCBM / MPMIC60

cTiO2

CH3NH3Pb(I1-xBrx)3

FTO-Glass

Au

mTiO2/CH3NH3PbI3

Spiro-OMeTAD

cTiO2

CH3NH3Pb(I1-xBrx)3

FTO-Glass

Au

mTiO2/CH3NH3PbI3

PTAA

PEDOT:PSS

CH3NH3PbI3-xClx

ITO-Glass

Al

PCBM

Ag

P3HT

ZnO

CH3NH3PbI3

ITO-PET

Ag

P3HT

ZnO

CH3NH3PbI3

ITO-GlasscTiO2

CH3NH3Pb(I1-xBrx)3

ITO-Glass

Ag

C60

Spiro-OMeTAD

Planar,

Large Grain

Perovskite

Acetate

Perovskite

(inverted)

Mesoporous

Perovskite w/

PTAA

Mesoporous

Perovskite w/

Spiro

Planar,

Slot-Die

Perovskite

Planar, Roll-

to-Roll

Perovskite

Acetate

Perovskite

(regular)

Spin withair flow

AirSpin withtoluene drip

toluene

Slot-Die

N2Roll-to-Roll

Hot-casting

Precursor MAI/PbAcO2 in DMF MAI/PbI2 in GBL/DMSO PbI2 in DMF and MAI in 2-propanol MACl/PbI2 in DMF

Delivery Spin coated with

compressed dry air flow

2-step spin coating process in N2 with

toluene drop-casted during second step

Sequential slot-die coating in air of PbI2and MAI heated at 70°C

Substrate heated

before spin coating

Post-

deposition

Annealed in dry air at 100°C

for 5 min

Annealed in nitrogen at 100°C for 10 min N2 gas quench None Cooled on glass

0.1

1

10

100

1,000

Fra

ctu

re E

nerg

y, G

c(J

/m2)

Dense SiO2

TEOS

SiO2ULK

dielectrics

Gc ~ 5 J/m2

Gc ~ 10 J/m2

Organics and OPV

CIGS

CuInxGa(1-x)Se2

Mo

CdS

Al doped ZnO

Al foil

Perovskites

Fundamental Challenge for Stability and Reliability

Silicon

PVPolymers for

Packaging

Encapsulation

Structural Materials

Protective

Coatings

Human

Skin (SC)

Rolston, et al., Extreme Mechanics Letters, 2016.

Rolston, et. al. Advanced Energy Materials, 2017.

Hilt, Hovish, Rolston, Dauskardt, E&ES, 2018.

Rapid Spray Plasma Processing (RSPP) of Perovskites

low-cost and scalable open-air

processing with compressed air

perovskites with improved

optoelectronic properties and stability

RSPP Spin-coated

Glass

ITO

MAPbI3PEDOT:PSS

C60/BCP

400 600 800 1000 12000,00

0,25

0,50

0,75

1,00

No

rma

lize

d a

bso

rba

nce

(a

.u.)

Wavelength, (nm)

RSPP

Spin-coated

RSPP Produces Highly Efficient Devices

MAPbI3

Glass

ITO

0

2

4

6

Fra

ctu

re E

nerg

y, G

c(J

/m2)

spin coated hot-cast* RSPP

superior mechanical

stability and fracture

resistance…

0.43 J·m-2

4.4 J·m-2

Hilt, Hovish, Rolston, Dauskardt, E&ES, 2018.

15.4% Efficiency15.7% Efficiency

1”

Perovskite

Solar Cell

Air Air

Plasma Deposition of Silica Barriers

Moisture Stability

ControlSiO2

HMDSO

TFT

Barrier film

MAPbI3

AuPTAA

C60/TiO2

ITO

0 1000 2000 30000.0

0.5

1.0N

orm

aliz

ed

PCE

Exposure time (hr)

85°C, 25% RH

degraded

perovskite

control

intact

perovskite

25% TFT

Rolston, et.al. J. Mat. Chemistry A, 2017.

A Scaffold Concept for Reliability and Efficiency

ITO-substrate

C60

compact TiO2

Perovskite

m-cell

PTAA-X

electrode

Sca

ffo

ld

Sca

ffo

ld

Encapsulant

Reflective Electrode

Transparent Electrode

Scaffold

Sequential Scaffold Filling

A Scaffold Concept for Reliability and Efficiency

laser beam induced current

0.00 0.15 0.30 0.45 0.60 0.75 0.90 1.05

-20

-15

-10

-5

0

Cu

rren

t D

ensity (m

A c

m-2

)

Voltage (V)

planar

50 µm

100 µm

scaffold wall width

300 400 500 600 700 8000.0

0.2

0.4

0.6

0.8

1.0

EQ

E

Wavelength, (nm)

200 µm

planar

50 µm

100 µm

200 µm

17.9 mA

14.3 mA

12.1 mA

6.9 mA

Micro-Lens Array Design and Scaffold Fabrication

lens arrays designed with optical modeling

lens array used to fabricate solar cells…fully self-aligning

Micro-Lens Array Design and Scaffold Fabricationwithout lenses with lenses

mm

mm

mm

mm

Micro-Lens Array Design and Scaffold Fabrication

Passive tracking by lenses for increased diurnal power efficiency…

Angle of incidence: 0° 15° 30° 45° 60°

0 5 10 15 200

5

10

15

20 Planar OPV

Fra

ctu

re E

ne

rgy, G

c (

J m

-2)

Efficiency, PCE (%)

Planar Perovskite

Scaffold-Partitioned Perovskite

lens arrayc-Si/CIGS modules

Conclusions…

• Big data has enormous potential to revolutionize

materials discovery and efficiencies…

…but, energy is a big and rapidly growing challenge

for big data and the IoTs

• Make IoT devices self-powered by harvesting

energy from their operating environment

• Sunshine is a plentiful and inexhaustible energy supply

• Perovskite solar cells are one of the most promising low-cost and efficient

solar PV materials with significant potential for improved materials

efficiency, but stability and reliability must be addressed

• New concepts in perovskite scalable spray-plasma processing and module

design concepts for reliable solar PV enable the use of significantly less

materials for longer