Dye-sensitized Solar Cells A smart way to solar electricity Maciej - - PowerPoint PPT Presentation

Dye-sensitized Solar Cells A smart way to solar electricity

Maciej Zalas

Smart Energy 2015

Civilization = Energy Consumption

Energy – The ability to perform work

www.financialsense.com/ Smart Energy 2015

Energy Sources

• scareducation.blogspot.it

Smart Energy 2015

Sun

Energy supply = 1.71017 W/Year Energy consumption of the planet Earth:

• Flora 11014 W/Year
• Humankind 1.31013 W/Year (2000)
• Humankind 2.81013 W/Year (2050)

Difference: 1.698721017 W/Year

http://goaskgrandpa.com Smart Energy 2015

Photovoltaics – The Beginning

Alexandre Edmond Becquerel 1820 - 1891 1839 – Photoelectric effect on Pt electrodes covered by AgCl or AgBr

http://www.rats-ms.de http://www.solartec.lu Smart Energy 2015

A bit of History

• 1883 – Charles Fritts described the first solar cell made from selenium

wafers.

• 1905 – Albert Einstein published his description of the phenomenon of the

photoelectric effect (Nobel Prize 1921)

• 1941 – Russell Shoemaker Ohl patented first silicon solar cell (h = 1 %)
• 1954 – First commercial solar cell introduced on the market by Bell

Telephone Laboratories (h = 6 %)

• 1958 – NASA launched first solar cells powered artificial satellite Vanguard I
• 1976 – David Carlson and Christopher Wronski produced the first amorphous

silicon photovoltaic cell (h = 1.1 %)

• 1991 – Brian O’Regan and Michael Grätzel invented the first high effective

Dye-sensitized Solar Cell (h = 7.8 %)

Smart Energy 2015

Photovoltaics – Efficiencies

by EPFL Smart Energy 2015

Dye-sensitized Solar Cells

• Medium or low-purity materials
• Simple preparation methods
• Relatively good efficiencies (recent record

h = 14.1 % acc. EPFL)

• Low costs

www.solarisnano.com Smart Energy 2015

Smart Energy 2015

DSSC – How it works?

Dye-sensitized Solar Cell

• Anode: Conducting glass covered by

semiconducting oxide sensitized by dye molecules

• Electrolyte: solution of redox mediator
• Cathode: Conducting glass covered by

redox catalyst

• K. C. D. Robson , P. G. Bomben, C. P. Berlinguette Dalton Trans., 2012,

41, 7814-7829

Smart Energy 2015

• Smooth surface; low surface area
• Low dye adsorption
• Low light harvesting
• Poor efficiencies (h < 1 %)

Semiconductor – Key to Success

Smart Energy 2015

• High surface area
• 1000 times higher dye adsorption
• High light harvesting
• Good efficiencies (h > 10 %)

Semiconductor – Key to Success

Smart Energy 2015

Dye-sensitized Solar Cell

• Anode: Conducting glass covered by

semiconducting oxide sensitized by dye molecules

• Electrolyte: solution of redox mediator
• Cathode: Conducting glass covered by

redox catalyst

• K. C. D. Robson , P. G. Bomben, C. P. Berlinguette Dalton Trans., 2012,

41, 7814-7829

Smart Energy 2015

Dye – Heart of the System

Natural dyes (Anthocyanines, Carotenoides, etc.)

• Very broad and strong absorption of Vis light
• Cheap and available (crude form)
• Poor stability (oxidation sensitive)

Smart Energy 2015

Dye – Heart of the System

Ruthenium dyes

• Broad and strong absorption of Vis light
• High stability in the cell conditions
• Strong binding to the semiconductor surface
• Adequate reduction and oxidation potentials
• Long term living excited state
• Expensive

Smart Energy 2015

Dye – Heart of the System

Synthetic organic dyes

• Tunable absorption of Vis light
• High stability in the cell conditions
• Strong binding to the semiconductor surface
• Adequate reduction and oxidation potentials
• Short term living excited state
• Tunable structure, synthesis and price

Smart Energy 2015

Dye-sensitized Solar Cell

• Anode: Conducting glass covered by

semiconducting oxide sensitized by dye molecules

• Electrolyte: solution of redox mediator
• Cathode: Conducting glass covered by

redox catalyst

• K. C. D. Robson , P. G. Bomben, C. P. Berlinguette Dalton Trans., 2012,

41, 7814-7829

Smart Energy 2015

Electrolyte – Binding Element

Iodine/Iodide electrolytes

• Corrosive towards metals and ”multiple

bonds”

• Adsorbs light towards blue part of the

spectrum

• Redox potential limiting Voc to 0.7-0.8 V
• Two electron redox mechanism
• K. C. D. Robson , P. G. Bomben, C. P. Berlinguette Dalton Trans., 2012,

41, 7814-7829

Smart Energy 2015

Electrolyte – Binding Element

• Noncorrosive
• Low absorption in visible region
• Facile tuning of redox potential
• One electron redox mechanism

Smart Energy 2015

Dye-sensitized Solar Cell

• Anode: Conducting glass covered by

semiconducting oxide sensitized by dye molecules

• Electrolyte: solution of redox mediator
• Cathode: Conducting glass covered by

redox catalyst

• K. C. D. Robson , P. G. Bomben, C. P. Berlinguette Dalton Trans., 2012,

41, 7814-7829

Smart Energy 2015

Counter Electrode – Last but not Least

• Best known redox catalyst
• Completely stable
• Easy to prepare electrodes
• Very expensive

www.periodictable.com

Smart Energy 2015

Counter Electrode – Last but not Least

Carbon electrodes

• Low charge transfer resistance
• High surface area
• Low costs
• Efficiencies comparable to Pt
• Relatively poor stability

http://cnx.org

Smart Energy 2015

Solar Cells – Characterization

Light

• c

sc

• c

sc max max Light max max d

P FF V J % 100 V J V J FF % 100 P V J V J P             h h

Smart Energy 2015

Thank You for Attention

Smart Energy 2015