CEAS REU Project 4 Synthesis of Solar Cell Materials, and Fabrication of Novel Polymer-Based Solar Cells Nathan Duderstadt, Chemical Engineering, University of Cincinnati Stoney Sutton, Electrical Engineering, University of Cincinnati Kate Yoshino, Engineering Physics, Taylor University Dr. Vikram Kuppa and Ms. Yan Jin

Introduction Why solar cells? Why ORGANIC solar cells? What is graphene and what role does it play?

Background Literature Review Solar Radiation Charge Generation In a semiconductor, the energy from the sun both moves the electron to an excited state, but also creates a hole (positive charge) in its place. Charge Transport to Electrodes Electric Current Lowest Unoccupied Molecular Orbital Highest Occupied Molecular Orbital e h Animation and concepts adapted from Dr. Vikram Kuppa’s presentation on organic photovoltaics

Organic Photovoltaic Devices The problem with semiconductors in solar cell applications is separating these particles and TRANSFERING them to their electrodes. In order to accomplish this, we use two material, like seen to the right. Picture from: Deibel, Carsten, and Vladimir Dyakonov. (2010). " Polymer–fullerene Bulk Heterojunction Solar Cells.." Vol. 73.9, pp. 1-39.

Active Layer (P3HT:F8BT:Graphene) Indium Tin Oxide (Anode) Cell Structure Aluminum (Cathode) Lithium Fluoride Active Layer (P3HT:F8BT:Graphene) PEDOT:PSS Indium Tin Oxide (Anode) Glass Slide The thickness of the cell is approximately without the glass slide is approximately 500 nm in thickness.

Cell Structure Solar Cell Active layer Indium Tin Oxide (Anode) Aluminum (Cathode) Glass Slide

Project Goal Project Objectives Determine how graphene makes solar cells more efficient Project Objectives Learn the basics of Organic Photovoltaic (OPV) research Gain expertise in making and characterizing OPV cells Understand methods of fabricating graphene from graphite Incorporate graphene in OPV cells Differentiate between processing techniques and their influence on the solar cell Evaluate graphene content on cell performance

Tasks Learn methods for making graphene solutions and fabricating solar cell devices Prepare and analyze graphene solutions for use in solar cell polymers Fabricate solar cell devices and perform thermal treatment Characterize the cell through various testing Conduct morphology and conductivity studies on the polymer films with different graphene concentrations Report writing and presentations

Timeline Week Task 1 2 3 4 5 6 7 8 Training: Make Graphene Solution, Fabricate Solar Cell   Graphene Solutions: Prepare, Characterize, and Blend Polymer Films: Make and Anneal Polymer Layers, Add to Cells Solar Cell Testing: Cell Efficiency for Varying Graphene Concentrations Work on Deliverables: Paper, Presentation, Poster

Research Training Received Lab Safety Training Making Graphene Solutions UV Spectrophotometer Blending P3HT and Graphene

Research Training Received Spin Coating Procedure Performance Testing Transmission Electron Microscope Atomic Force Microscope

Progress Made Training is mostly complete! Created first set of cells (during training) Tested first set of cells Currently processing data Started beginning processes of creating second batch with varying concentrations

Questions?