Organic Photovoltaic Device Lab
| K-12 Outreach Kits and Labs |
Overview
One of the hottest research areas is the development of polymer based photovoltaic devices that can be printed. The technology requires a convergence of disciplines of physics, chemistry, materials science and engineering. Much of the research is conducted in organic chemistry labs in which new compounds, and systems of chemicals are designed and synthesized. Building the devices that practically use this chemicals is an engineering problem solving enterprise. Now some proven chemical systems are commercially available opening the possibility of bringing the device construction and characterization into the undergraduate chemistry or physics lab.
In this lab students will spin coat a multilayered organic photovoltaic device and then characterize its physical structure and performance.
<swf width="500" height="400">http://depts.washington.edu/cmditr/media/opvanim.swf</swf>
Procedure
The device is some variation of p3ht/pcbm on a layer of pedot-pss.
Standard UW constuction
- Clean ITO coated slides as substrate
- Spin coat substrate with pedot-pss in normal atmosphere)
- Spin coat p3ht/pcbm blend also called the bulk heterojunction BHJ in nitrogen
- Anneal device in oven to increase domain and channel size
- Evaporate/vacuum coat the aluminum top contact
- Characterize the device
Variables to investigate
- Thickness of BHJ layer
- Nanowires or nanodots in BHJ layer
- Variation is annealing time
- Variations on top contact
- Variation is pedot-pss layer
Characterization
Spectral Characterization
- Measure the transmittance of the organic layers with a spectrometer
Device Characterization
- Measure the current voltage curve using probeware. see PV_Characterization_Lab
Other
- AFM measurement of surface of heterojunction interface
- profilometer or AFM measurement of the thickness of layers
- measurement of performance under degrading conditions of light, oxygen and water.
Further Research
References
- Polymer-based Materials for Printed Electronics: Enabling High Efficiency Solar Power and Lighting Material Matters 2008, 3.4, 92.
- Plexcore Ink system instructions
- OLEG OPV instructions using PCBM:MDMO-PPV with PEDOT PSS and Gallium Indium eutectic as cathode
- Guo, Q.J., Hillhouse, H.W., Agrawal, R., "Synthesis of Cu2ZnSnS4 Nanocrystal Ink and Its Use for Solar Cells," J. Am. Chem. Soc. 131 (33), 11672"11673 (2009).{DOI|10.1021/ja904981r}