1. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA
2. Department of Materials Science and Engineering Sharif University of Technology 14588 Tehran Iran
3. Department of Solar Energy School of Technology Pandit Deendayal Petroleum University Gandhinagar Gujarat 382 007 India
4. Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 Warsaw 01-224 Poland