RCAST：Research Center for Advanced Science and Technology Research Center

International Research Center for Energy and Environmental Technology

SOLAR QUEST

GENNAI：Global Energy Navigating and Nature Apprehension Interdisciplinary (Gennai HIRAGA)

・Research & Development・Technology Development Strategy ・Exploitation Strategy

http://gennai.rcast.u-tokyo.ac.jp/

RCAST, Research Center for Advanced Science and Technology

Main Objectives & Principles;Interdisciplinary approach, mobility, international perspective, and

openness

Solar Quest 2008

SOLAR QUESTRCAST, The Univ. of Tokyo

Organizations

Leader: Prof. Yoshiaki Nakano, The University of Tokyo, RCASTVice leaders: Prof. Masafumi Yamaguchi, Toyota Technological Institute

Prof. Takashi Tomita, The University of Tokyo, RCAST

Team 1: Super high efficiency concentrator multi-junction solar cellsLeader：Prof. Masafumi Yamaguchi, Toyota Technological Institute

Team 2: High efficiency quantum structure tandem solar cells and their manufacturing technologies

Leader： Prof. Yoshiaki Nakano, The University of Tokyo, RCAST

Team 3: Ultra-high efficiency solar cells based on quantum dots and superlatticeLeader： Prof. Yoshitaka Okada, The University of Tokyo, RCAST

Team 4: Ultra-high efficiency multiple junction solar cells with hybrid materialsLeader： Prof. Hiroshi Segawa, The University of Tokyo, RCAST

Toyota Technological

Institute

Kyushu Univ.

Miyazaki Univ.

Meijo Univ.

SHARP Corp.

The Univ. of Tokyo

The Univ. of Electro-Communications

Nippon Oil Corp

Osaka Univ.,

University of

Hyogo

InternationalCollaborationJoint-research

DOE/ANLNRELASUStanfordLBNLUC BerkeleyUCSBICLGlasgow U.UNSWEPFLetc…

SHARP Corp.

The Univ. of Tokyo

The Univ. of Tokyo

Nippon Oil Corp

SOLAR QUEST

Tundem

Quantum

hybrid

multiband

III

Cost ($/m2)

$0.10/Wp $0.20/Wp $0.50/Wp

Effi

cien

cy (%

)

20

40

60

80

100

100 200 300 400 500

$1.00/Wp

$3.50/Wp

Thermodynamic limit at 1 sun

Shockley-Queisserlimit: Single junction

0

a-Si タンデム

多結晶Si

単結晶Si

III-VConcentrator

by 2030

Cost ($/m2)

$0.10/Wp $0.20/Wp $0.50/Wp

Effi

cien

cy (%

)

20

40

60

80

100

100 200 300 400 500

$1.00/Wp

$3.50/Wp

Thermodynamic limit at 1 sun

Shockley-Queisserlimit: Single junction

I: bulk SiII: thin film

dye-sensitizedorganic

III: next generation

I: bulk SiII: thin film

dye-sensitizedorganic

III: next generation

0

Thin film

a-Si

poly Si

Si

III-V

by 2030

tandem

amorphoustandem

Post-Silicon Solar Cells for Ultra-High Efficiencies

Motivation & Objectives

Current: Limit of 31% efficiencySingle junction1 photon 1 e-h pairThermalization to band edge

Eg

Multi-junction Multi-band

Heat dissipation3V

3i

Multipleexciton

Hot carrier

Plasmon Fine structure

Photon management

Our project

Novel hybrid material

III-V compound semiconductor multi-band cells with concentrator conversion efficiency above 45% by...(1) Inverse lattice-mismatch growth, (2) Quantum-structure middle cells(3) InGaAsN middle cells

High-efficiency multi-junction cells

Super high-efficiency multi-band cells

Novel materials and concepts

III-nitride semiconductors, Organic and inorganic complex materials, Photon management by nanoparticles

Quantum structure super-lattice with coupled quantum energy levels that functions as a multi-band cell, leading to a conversion efficiency of above 50%

R&D for ultra-high efficiencies

Crystal growth Cell Moduledesign

AlInGaP

GaAs

InGaAs

InGaAs

1.0eV

1.4eV

0.65eV

2.0eV

ILMM growth

novel materials and structures

48%(x1000)

InGaN

InGaAsN

Quantum structures(wells, dots)

Reuse forEpi-growth

GaAsGaAs substrate

Back Electrode

Front Electrode

graded buffer

InGaP Top (1.88eV)

GaAs Middle (1.42eV)

InGaAs Bottom (1.0eV)

Si support substrate

Lattice mismatch

Lattice match

All-InGaN tandem

InGaAsN

AlInGaP

InGaAs

Ge

1.0eV

1.4eV

0.67eV

2.0eV

InGaAs+QS

AlInGaP

InGaAs

Ge

1.0eV

1.4eV

0.67eV

2.0eV

Computational chemistry

Mul

ti-ju

ncti

on c

ells

Circuit designDevice simulation

Thermal management

Micro-nanofabrication

Theoretically 60%Experimental demonstration >15% (x1)

Quantum structure multi-band cells

Novel hybrid materials

Photon management (plasmon etc.)

Novel concept cell design

SHARP Corp.

SHARP Corp.

CBE

Toyota Technological Institute

MBE+H beam

The Univ. of Tokyo

Okada

Dots

The Univ. of Tokyo

Okada

Wells

The Univ. of Tokyo

InGaAs/GaAsP: NakanoInGaAsN/GaAs: Onabe

Meijo Univ.

MOVPE PXD

The Univ. of Tokyo

Fujioka

Kyushu Univ.

Toyota Technological Institute

Meijo Univ.

Miyazaki Univ.

Toyota Technological Institute

Miyano

The Univ. of Tokyo

Nakano SHARP Corp.

Quantum dots superlattice

The Univ. of Tokyo

Okada

The Univ. of Electro-Communications

Nippon Oil Corp

n- and p-type mixed materials

Indium free inorganic materials

Osaka Univ.,

Metal nanoparticlessurface complexes

The Univ. of Tokyo

Tatsuma

ETA (Extremely Thin Absorber) type solar cells

Interfacial charge transfer transition type solar cells

Cu compounds(CIS,CIGS etc.)

University of Hyogo

Organic hole transport materials

RO OR

RO

RO OR

OR

R SS

S R

ORR

The Univ. of Tokyo Segawa

The Univ. of Tokyo

Segawa

The Univ. of Tokyo

SHARP Corp.

48%(x1000)

GENNAI @ SOLAR QUEST

1. Exploitation of Solar Energy (Global, Security)

2. Direction of Technology Development (c-Si, Thin film Si, organic, New concept, System)

3. Global Environmental Issues

(Solar among other renewable energies)

4. Energy Supply (Supply/Demand issues)

5. Proposition to Policymaking

GENNAI covers a broad range oftopics with special emphasis on solar energy

1. High purity and low cost manufacturing of New Si (SOG and large size sheet bulk Si)

2. Third generation cells: multi-junction, III-V compound semi-conductor…

3. Solar concentrator and other systems including solar thermal

4. Power generation with smart grid

GENNAI focuses on;

1. Innovative New Si(SOG) Manufacturing Technology

Conventional method（純度:6-11N)

SiO2MG-Si

SiHCl3SiCl4

Poly-Si Ingot

New method(純度:6-8N)

SiO2 HG-Si

Large SizeSheet

INGOT

Much Power Consuming process

Lower Power Consuming process

WAFER

Based on Prof. Shingu, Kyoto Univ.Supported By NEDO

2. Architecture of Photovoltaic Cells and System

• How to Jump?

1st Generation η１２－２０％c-Si (Mono-c and Poly-c), Conventional Grid Connection

2nd Generation η６－１２％Thin Film a-Si, micro-c-Si, CIGS, CdTe…

3rd Generationη３０－６０％

Smart Solar ArchitectureNew Silicon + III-V Compound + Quantum

Dot and Organic or Hybridし

3.1 Solar concentrator and other systems like solar thermal

Solar Concentrator for 3rd Generation Cells and for Solar Thermal

Large Fresnel Lenz for Solar PV and ThermalLenz size:3.3mx3.3m segmented to 9 sect. Theoretical temp: 2500deg.C

Small Fresnel Lenz for Solar PV and ThermalLenz size: 0.6mx0.6m

3.2 Tracking system of single and double axes

3.3 Large Scale PV and Solar Thermal Concentrator

12

3

1. Solar Heat Tower

2. Direct Steam Generation

3. Solar Photovoltaic Tower

3.4 Large Scale PV in a desert

Fiscal ＹＥＡＲ

1

10

100

1,000

10,000

2000 2008 2010 2020 2030 2040

Ann

ual M

arke

t (G

W/y

ear)

c-Si super straight type

Thin film

Organic & Other materials

New Si

Ⅲ-Ⅴ compound with concentrator

PV Cell Portfolio

0.1

3.7GW

7.8ＧＷ

Published by Tomita, San Francisco ２００３

200 Nuclear power stations equivalent

DOE Private Funds NEDO

Synergy

•Very High Efficiency Cell Technology•System Improvement Technology

Module interconnectionNew power electronicsVery high voltage PV systemsLarge Secondary Battery

•Silicon Materials•Organic Materials•Strong Policy and Funding Strategy

Partner Institution

University of Tokyo

“GENNAI”

•Strong Technology

•Strong Policy or Funding Strategy

• Strong Environmental or Political Incentives

$10M

Lots of

Sunshine

/ http://gennai.rcast.u-tokyo.ac.jp/