AVS 53rd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoA

Paper EM-MoA6
Carbon Nanotube Based Transparent Contacts for Photovoltaics

Monday, November 13, 2006, 3:40 pm, Room 2003

Session: Contacts, Interfaces and Defects in Semiconductors
Presenter: T.M. Barnes, National Renewable Energy Lab
Authors: T.M. Barnes, National Renewable Energy Lab
J. van de Lagemaat, National Renewable Energy Lab
M. Contreras, National Renewable Energy Lab
G. Rumbles, National Renewable Energy Lab
S.E. Shaheen, National Renewable Energy Lab
T.J. Coutts, National Renewable Energy Lab
C.L. Weeks, EIKOS, Inc
I.A. Levitsky, EIKOS, Inc
J.A. Peltola, EIKOS, Inc
P.J. Glatkowski, EIKOS, Inc
D.A. Britz, EIKOS, Inc
Correspondent: Click to Email
Transparent electrodes are an integral part of photovoltaic (PV) devices, and the transparent conducting oxide (TCO) films currently in use are not ideal for all PV applications. Nanostructured bundles of single wall carbon nanotubes (SWCNT) can be solution-deposited to form highly conductive and transparent thin films. The films consist of entangled bundles of SWCNTs with a large fraction of void space. The optoelectronic properties of the SWCNT films approach those of commonly used TCO films. Unlike ZnO and other traditional TCOs, however, the SWCNT film has little absorption in the visible or near infrared. Furthermore, in stark contrast to other available TCO materials, the SWCNT films are essentially hole conductors due to the intrinsic p-type conductivity of the SWCNTs. In this paper, we demonstrate the utility of SWCNT-based transparent contacts on several different types of thin-film solar cells. First, they were successfully used to replace ZnO in high-efficiency CIGS devices. Second, the SWCNT coating was used to replace ITO and PEDOT:PSS in excitonic, bulk heterojunction devices, resulting in an exceptionally high efficiency for a device without indium or PEDOT:PSS. These coatings work well in excitonic devices because the large void fraction allows for interpenetration of the active polymer at the nanoscale. They are also highly amenable to use on flexible substrates. This abstract is subject to government rights.