[1] Univ Stuttgart, Inst Photovolta ipv, D-70569 Stuttgart, Germany
[2] Forschungszentrum Julich, IEK5 Photovolta, D-52425 Julich, Germany
[3] Univ Jaume 1, Inst Adv Mat, Ave Vicent Sos Baynat S-N, Castellon de La Plana 12006, Spain
[4] Univ Valencia, Inst Ciencia Mat ICMUV, C-Catedrat Jose Beltran 2, Valencia 46980, Spain