New Integration Approaches for Highly Arrayed Nanostructures for Organic/Inorganic Solar Cells

Special interest continues to grow in the achievement of fundamental understanding of nanostructured assemblies that potentially open new horizons for creating novel energy conversion systems. When one-dimensional (1D) nanostructures based on nanotubes or nanowires are integrated into the assembly of well-ordered architectures, they exhibit a variety of tunable optical and electrical properties that can offer exciting opportunities in creating the next generation of solar cells.  Recently, particular focus has been placed on nanostructured solar cells that can tolerate a higher level of defects and impurities. To realize their potential, semiconducting 1D nanostructures that serve as conducting scaffolding and absorbing layers should be controlled in a predictable and precise fashion in order to efficiently tailor photon harvesting and transport charge carriers [1,2,3]. While the past several years have witnessed great progress in the area of nanotechnologies, structural dimensions (height, thickness, and spacing) and spatial alignment of 1D nanostructures have not been shown to be selectively controllable with high precision [4].  Accordingly, current nanofabrication technologies allowing for precise control over the assembly of 1D nanostructures yielding optimal architectures of nanostructured solar cells are still in their infancy. Hence, a scarcity of ideal platforms consisting of highly-controlled nanostructure assemblies makes use of non-ideal systems, thereby preventing systematic studies of energy conversion processes within the cell and at the heterojunction interfaces. Therefore, we provide novel approaches to investigate material synthesis for highly arrayed nanostructured systems for solar cell applications.

We developed a new process technology that can make full use of the porous template while structural dimensions such as spacing and thickness of nanostructures are also precisely controlled. Particularly, our technologies enable highly arrayed nanostructures having various material combinations such as insulators, semiconductors, and/or metals. In addition, they allow for large-scale production of such highly arrayed nanostructures. Currently, we are integrating highly arrayed nanostructures into glass or plastic substrates. Our nanofabrication technologies will provide a new class of highly arrayed, multi-walled nanostructures suitable for many optoelectronic applications including new-generation solar cells.

References

1. Z. Fan, H. Razavi, J. W. Do, A. Moriwaki, O. Ergen, Y. L. Chuen, P.W. Leu, J.C. Ho, T. Takahashi, L. A. Reichertz, S. Neale, K. Yu, M. Wu, J.W. Ager, and A. Javey, Nat. Mater. 8, 648 (2009)
   1. L. Sun, S.Zhang, X. Sun, and X. He, J. Nanosci. Nanotechnol., 10, 4551 (2010)
   2. V. Thavasi, V. Renugopalakrishnan, R. Jose, and S. Ramakrishna, Mater. Sci. Eng. R. 63, 81(2009)
2. A. Belaidi, Th. Dittrich, D. Kieven, J. Tornow, K. Schwarzburg, M. Kunst, N. Allsop, M.-Ch. Lux-Steiner, and S. Gavrilov, Sol. Energy Mater. Sol. Cells, 93, 10336 (2009)