Evolution of High Effiency Silicon Solar Cell Design: Lecture 1

Australian Centre for Advanced Photovoltaics

“Evolution of High Efficiency

Silicon Solar Cell Design”

Martin A. Green University of New South Wales

UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight Annual capacity increase

Wind 45

36 Gas Turbines

New Capacity, GW New Capacity, . 27

18 Photovoltaics

0 Nuclear 2005 2006 2007 2008 2009 2010 2011 2012 UNSW PhotovoltaicsSources: - Electricity EPVIA, from SunlightIAEA, GWEA Ultimate potential? 2003

50.7 Terawatt

UNSW Photovoltaics - Electricity from Sunlight “Submerged” progress

100000 25% 10000 World’s energy

1000 Nuclear

Wind

100

Installed capacity, GW WBGU Scenario 1% milestone 1% World’s Projected Wind Actual electricity WBGU PV 10 PV Projected Actual PV 1% milestone PV WBGU Nuclear Actual Nuclear 1 2000 2010 2020 2030 2040 2050

UNSW Photovoltaics - Electricity from Sunlight German grid : May 2012

Actual production DE 30GW wind; 25GW PV 5/12 Peak demand 68GW (30% solar) displayed month: May 2012 MW 60,000

50,000 40,000

30,000 20,000 Peak conventional 51.2GW 10,000 Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Legend: Conventional > 100 MW Wind Solar

UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight The beginning

UNSW Photovoltaics - Electricity from Sunlight The first solid-state cell

UNSW Photovoltaics - Electricity from Sunlight The first thin films

UNSW Photovoltaics - Electricity from Sunlight The first PV visionary

UNSW Photovoltaics - Electricity from Sunlight Cuprous oxide cells

“spitting on a penny”

UNSW Photovoltaics - Electricity from Sunlight The 1930s

Schottky diode

UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight The first silicon pn junction cell (Russell Ohl, 1941)

UNSW Photovoltaics - Electricity from Sunlight The first silicon pn junction cell (Russell Ohl, 1941) William Shockley

UNSW Photovoltaics - Electricity from Sunlight The first silicon pn junction cells (Russell Ohl, 1941 & 1951)

UNSW Photovoltaics - Electricity from Sunlight The first efficient cells (1953/4) Pearson, Chapin & Fuller

UNSW Photovoltaics - Electricity from Sunlight The first efficient cells (1953/4)

UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight The first efficient cells (1953/4) 25

20 UNSW

10 Efficiency, %

0 1940 1950 1960 1970 1980 1990 2000 2010 UNSW Photovoltaics - Electricity from Sunlight Conventional space cell

Vanguard I (1958)

UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight Re-cap: pn junction theory

“Superposition” UNSW Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight Conventional space cell

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight Conventional space cell

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Violet” cell (1972)

1. Light top diffusion (no dead layer)

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Violet” cell (1972)

1. Light top diffusion (no dead layer) 2. Photolithographically defined top contacts 25

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Violet” cell (1972)

1. Light top diffusion (no dead layer) 2. Photolithographically defined top contacts 25 3. Rear Al BSF (back surface field)

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Violet” cell (1972)

1. Light top diffusion (no dead layer) 2. Photolithographically defined top contacts 25 3. Rear Al BSF (back surface field)

UNSW 4. Higher index AR coating 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Violet” cell (1972)

1. Light top diffusion (no dead layer) 2. Photolithographically defined top contacts 25 3. Rear Al BSF (back surface field)

UNSW 4. Higher index AR coating 20 5. Higher doped substrate (2 ohm_cm)

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Black” cell (1974)

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight “Black” cell (1974)

UNSW 20

15 Efficiency, % Efficiency,

UNSW 1940 1950 1960 1970 1980 1990 2000 2010 Photovoltaics - Electricity from Sunlight Outline –Lecture I

1. Recent developments 2. Early PV history 3. The first pn-junction 4. Conventional space cells 5. Key pointers pn junctions 6. Enter the modern era -Questions-

UNSW Photovoltaics - Electricity from Sunlight