New book: The Photophysics Behind Photovoltaics and Photonics

15 06 2012

Organic solar cells and dye solar cells are increasingly relying on sophisticated and improved photophysical processes. This topic has become very important across the last decade and now, everyone involved in the research needs to have an idea about  photoexcitation dynamics, charge transfer, and similar topics. This new book, “The Photophysics Behind Photovoltaics and Photonics”, covers the basic physics of this field and many useful applications.

The author, Guglielmo Lanzani, is Head of the Center for Nano Science and Technology of the Italian Institute of Technology (IIT@POLIMI) and associate professor of Physics at the Politecnico di Milano, Italy. Having obtained his academic degree from the University of Genova, he spent five years as a researcher in Sassari, before taking up his present appointment at Politecnico di Milano, and more recently at IIT. Professor Lanzani has authored over 180 scientific publications, and has given 65 invited talks. He is a member of several conference program boards and chair of international conferences.

Prof. Lanzani is also coordinator of the European FP7 project PHOCS, Photogenerated Hydrogen by Organic Catalytic Systems, that is very hopefully just going to start (as announced today), with cooperation of Universitat Jaume I, EPFL and other eminent centers on the water splitting with semiconductors…

Private Empire: a tale about the big oil companies

2 06 2012

Private Empire: ExxonMobil and American Power is a very interesting book. It tells the story of the giant American company Exxon, from the catastrophe of oil carrier Exxon Valdez in 1989, through the changing policies of the multinational company in response to all the political changes in the 1990s. This was in fact an epoch of turmoil in which the former global political blocs disappeared, and countries in Middle East, Africa and South America took hold of the control of oil resources. Nonetheless Exxon prevailed by adapting itself to changing times. Steve Coll explains very well how the company builds a common system of beliefs, and style, that makes a number of people about 150,000 to operate as a single team, with common goals and responses to identified problems and needs.

Another important piece of the story is how the company fiercely opposed all means to relieve climate change by reducing carbon emission, starting from a strong denial of the general chief executive, Lee Raymond, to the Kyoto Protocol in 1997, by recommending the communist government of the People´s Republic of China to oppose the policy of Clinton´s USA administration.  It is then described the ensuing years of ideological battle in Washington, in which the oil companies would lobby to deny the reality of carbon emission based climate change: “Strategists created layers of disguise, subtlety, and subterfuge—corporate-funded “grassroots” programs and purpose-built think tanks, as fingerprint-free as possible. In such an opaque and untrustworthy atmosphere, the ultimate advantage lay with any lobbyist whose goal was to manufacture confusion and perpetual controversy. On climate, this happened to be the oil industry’s position (p. 86)… The corporation’s advocacy campaigners (followed) a subtle strategy involving the use of money to advance corporate interests by exploiting the uncertainties and argumentation that can be innate to science (p. 87).”

P.S. august 2012

while working on my book I have found some outstanding scientific papers signed by people I much admire and I see they were working for Exxon at that time:

Cody, G. D.; Tiedje, T.; Abeles, B.; Brooks, B.; Goldstein, Y. “Disorder and the Optical-Absorption Edge of Hydrogenated Amorphous Silicon”. Physical Review Letters 1981, 47, 1480-1483.

Yablonovitch, E. “Statistical ray optics”. J. Opt. Soc. Am. 1982, 72, 899-907.

The fall of Konarka

2 06 2012

Konarka, the flagship company of organic solar cells in USA and Europe, filled bankruptcy yesterday 1st june in Massachusetts.

According to BloombergBusinessweek , the company had raised at least $189 million in venture capital since 2001. Konarka together with other thin film solar cell producers succeeded to attract strong investment when the price of  polysilicon, the raw material in conventional panels, steadily increased and peaked at $475 a kilogram in 2008. After major supply facilities started operation, the material’s average spot price has since fallen to $23.20 a kilogram. The price of the silicon panels fell 50 percent due to oversupply and production expansion in China.

Howard Berke, chairman, president and CEO of Konarka, said, “Konarka has been unable to obtain additional financing, and given its current financial condition, it is unable to continue operations. This is a tragedy for Konarka’s shareholders and employees and for the development of alternative energy in the United States.”

Organic solar cells are made with a combination of organic materials that even in small quantities absorb light with great efficiency and produce a photocurrent. The technology is potentially very powerful for the roll-to-roll or printed production of lightweight, flexible solar cells. Along the 2000 decade the power conversion efficiencies where not impressive, but in the last years the discovery of new materials that absorb a wider portion of the solar spectrum, and the control of morphologies of the blend and contact, has sent the efficiencies ramping up past 10%. Despite the unfortunate fate of the pioneering company, the demonstrable progress in efficiencies and robustness of materials and devices that we have witnessed, make this solar cell technology a powerful candidate for large scale renewable electricity production.  The major problem is still the stability of the solar cell, that’s why many technological efforts are directed towards robust encapsulation that will counteract the degradation of the organic materials under photovoltaic operation caused mainly by atmospheric gasses penetration. Another strong line of development is the construction of tandem cells, that couple two or more cells in series for more optimal harvesting and treatment of the solar photons. A number of European FP7 projects are improving these organic solar cell technologies focusing on the integration of solar cells in buildings, see

Sunflower project

X10D project