Large-area, solution-processed, graphene laminates are of interest for a number of applications in renewable energy. Interest stems from their ease of preparation, by vacuum filtration of suspensions of graphene oxide [1] or exfoliated graphene flakes [2]. Over the last few years, our group has worked on two essential optimization processes of graphene laminates for solar energy and, specifically: i) investigation of their work function for efficient photocarrier collection and ii) improvement of their thermal conductivity for efficient heat evacuation from plastic photovoltaics and mitigation of their degradation.In order to investigate the work function of graphene laminates, we used Kelvin Probe Force Microscopy, in the dark and under Far-Field and Near-Field Scanning Optical Microscope illumination. We observed a significant photoinduced increase in the open circuit voltage in thin film solar cells assembled on graphene laminates, which corresponds to similar changes in the electronic work function of the graphene electrode. The observed phenomena are in agreement with a dynamic graphene-insulator-metal model taking into account the specific photophysical properties of graphene as a zero-band gap semiconductor.We also optimized the nanoscale thermal properties of graphene laminates for solar cells [3]. Measuring and modeling their thermal conductivity requires considering they are formed by jigsaw puzzles of graphene platelets of different size and orientation. For sufficiently large platelets, the influence factor in controlling the thermal conductivity is represented by the interfacial thermal resistivity between neighboring platelets. This observation allowed us to derive a model which predicts their thermal conductivity and is general enough to be applied to a large class of graphene nanocomposites, [4] including graphene-PEDOT:PSS electrodes.G. Eda, G Fanchini et al Nature Nano 3 :270 (2008).F Sharifi et al Small 12 :699 (2012)MS Ahmed et al Carbon 61 :595 (2013)S  Ezugwu et al Thin Solid Films 534 :520 (2013)

Thermal and surface properties of graphene laminates for solar energy applications

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.