[1] Tech Univ Ilmenau, Inst Phys, Postfach 100565, D-98684 Ilmenau, Germany
[2] Helmholtz Zentrum Berlin, Inst Solar Fuels, D-14109 Berlin, Germany
[3] Humboldt Universiat Berlin, Inst Phys, D-12489 Berlin, Germany
[4] Cis Forschungsinstitut Mikrosensorik & Photovolta, D-99099 Erfurt, Germany