Elucidating efficiency losses in cuprous oxide (Cu₂O) photovoltaics and identifying strategies for efficiency improvement

In this thesis, I fabricated and characterized a series of thin-film cuprous oxide (Cu₂O) photovoltaic devices. I constructed several different device designs, using sputtered and electrochemically deposited Cu₂O. Characterization was done using XRD, SEM, optical spectroscopy, quantum efficiency, current-voltage, and capacitance-voltage measurements. Then, these devices were modeled using SCAPS-1D, a numerical simulation package, as well as MATLAB for analytical solutions. This simulation enabled a quantitative breakdown of efficiency losses in Cu 20 devices. Simulations suggest that low device efficiencies of 0.3-0.6% may be explained in part by poor bulk transport properties in the Cu₂O. However, the predominant efficiency loss comes from an unoptimized p-n heterojunction, in which a large negative conduction band offset and structural defects lead to a low built-in voltage and high recombination activity. The effects of interface engineering are demonstrated in experiment and simulation. Broader simulations suggest opportunities for future efficiency improvements towards 10%. These include the improvement of bulk properties, the selection of alternative pairing materials, novel device structures, and the possibility of multijunction cells.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2013

Author dc:creator

• Brandt, Riley Eric

Advisor dc:contributor.advisor

• Tonio Buonassisi.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/81593

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/81593