1. Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-601 74 Norrköping, Sweden
2. Wallenberg Wood Science Center, Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden
3. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Campus Umeå, SE-901 83 Umeå, Sweden