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 oscareducation.blogspot.it Smart Energy 2015

Sun Energy consumption of the planet Earth:  Flora 1  10 14 W/Year  Humankind 1.3  10 13 W/Year (2000)  Humankind 2.8  10 13 W/Year (2050) Difference: 1.69872  10 17 W/Year http://goaskgrandpa.com Energy supply = 1.7  10 17 W/Year Smart Energy 2015

Photovoltaics – The Beginning http://www.rats-ms.de http://www.solartec.lu Alexandre Edmond Becquerel 1839 – Photoelectric effect on Pt 1820 - 1891 electrodes covered by AgCl or AgBr 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 Gr ä tzel 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

DSSC – How it works? 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

Semiconductor – Key to Success  Smooth surface; low surface area  Low dye adsorption  Low light harvesting  Poor efficiencies ( h < 1 %) Smart Energy 2015

Semiconductor – Key to Success  High surface area  1000 times higher dye adsorption  High light harvesting  Good efficiencies ( h > 10 %) 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 V oc 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   P J V d  J V h   max max 100 % P Light  J V   max max FF 100 %  J V sc oc   J V FF h  sc oc P Light Smart Energy 2015

Thank You for Attention Smart Energy 2015