1. Hybrid Solar Cells, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33014Tampere, Finland
2. Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, School of Electronic Science and Engineering & International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi’an Jiaotong University, 710049Xi’an, China
3. Surface Science Group, Photonics Laboratory, Tampere University, P.O. Box 692, FI-33014Tampere, Finland
4. Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, FI-02150Espoo, Finland
5. Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33014Tampere, Finland
6. Laboratory of Molecular Science and Engineering, Åbo Akademi University, Henriksgatan 2, FI-20500Turku, Finland
7. Department of Applied Physics, Aalto University, FI-00076Aalto, Finland