UC San Diego
Graphene/Silicon Schottky Junction Based Solar Cells
- Author(s): Yavuz, Serdar
- Advisor(s): Bandaru, Prabhakar R
- et al.
After experimental discovery in 2004, graphene is one of the most extensively studied materials in last 15 years. The sp2 bonded carbon atoms in honeycomb geometry in the atomic thickness leads to use of graphene in many applications including but not limited to sensors, field effect transistor, batteries, photo detectors, super capacitors, diodes. In particular, the highly conductive, highly transparent (97.7%) and mechanical flexibility of graphene indicated its use as a transparent conductive electrode (TCE). As a new emerging material for TCE applications, the incorporation of graphene with well-studied silicon leads to a new photovoltaic area: Graphene/Silicon (Gr/Si) solar cell. Over the course of 8 years, the efficiency has been improved up to 17%.
After a brief introduction in chapter 1 and 2, chapter 3 introduces a promising alternative as incorporation of two-dimensional materials for Gr/Si solar cell. It is shown that applying graphene oxide via a simple spin coating process increases the efficiency of solar cell by a factor of three. A detail analysis of factors that contributions PCE enhancement are discussed. This chapter highlights the use of graphene oxide as an antireflection coating in Gr/Si solar cell.
In chapter 4, the highest efficiency Gr/Si solar cell is presented. Through a detail analysis and addressing the efficiency limiting parameters, a more effective doping along with an engineered design is discussed. The experimental studies and related discussions of the highest efficiency graphene/n-silicon (Gr/n-Si) solar cell is highlighted.
In chapter 5, It is demonstrated that the modifying the work function of graphene through an n doping allows us to use graphene as an electron extraction layer. A detail analysis and effective doping methodologies yielded the highest efficiency Gr/p-Si solar cell obtained so far. In addition, it is demonstrated that the one of most critical aspect of Gr/Si solar cells, stability, can be address through the use of aluminum oxide.
In chapter 6, a future direction for the possible efficiency improvements of Gr/Si solar cells by incorporating new doping strategies and materials for graphene is discussed. A strategy following the foot prints of p-n junction counterparts is provided for future studies.