Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Photovoltaics: Nanostructured materials

HL 30.3: Talk

Tuesday, March 17, 2015, 10:45–11:00, ER 164

Patterned growth of ZnO nanorods as light scatterers for photovoltaic application — •Nivedita Yumnam and Veit Wagner — Jacobs University, Campus Ring 1, 28759 Bremen, Germany

One of the major loss mechanisms in solar cells is due to inefficient absorption in active semiconductor layer. The absorption can be enhanced by incorporating ZnO nanorods. They can act as scattering centers of light and hence, they increase the optical path length of light. To grow ZnO, electrochemical deposition is employed since it can be done at relatively low temperature and hence, it is compatible for flexible substrates like PET (Polyethylene terephthalate). ZnO nanorods are grown on Au coated PET. Direct electrochemical deposition on Au/PET yields a very dense ZnO nanorod distribution, which is cumbersome for infiltration of semiconductor polymer. In order to tune the density of ZnO nanorods, self-assembled monolayer (SAM) of 1-octadecanethiol is applied on top of the Au surface. By doing so, the ZnO nanorods grow through the pinholes of the SAM layer, whilst creating gaps between them. The size of the ZnO nanorods is systematically varied by changing the parameters of electrochemical deposition such as temperature, growth time, concentration and voltage. An ultrathin layer of Au is sputter coated on top of the nanorods to improve the reflection characteristics. Angle resolved light scattering measurements are carried out to document the beneficial impact of these nanorods on the light scattering properties.