Fabrication of CdTe nanorod arrays over large area through patterned electrodeposition for efficient solar energy conversion

Development of solar energy conversion devices based on nano-fabrication techniques is the key to next generation photovoltaics. However, low throughput and complicated production procedures have limited their emergence at commercially relevant scales. In this article we report an inexpensive, high-throughput, versatile and reproducible technique for fabrication of vertically aligned CdTe nanorod arrays with coverage over a significantly large area through selective electrodeposition (PatED) on lithographically patterned nanoelectrodes. The nanoelectrodes are patterned using the Nanosphere Photolithography (NPL) technique which uses size-controlled polystyrene spheres as microlenses to focus light into photonic jets on an underlying photoresist. The nanorod diameter and pitch could be controlled through optimization of the NPL process. This generalized technique provides a way for production of wafer-scale nanorod arrays on conducting surfaces for solar energy conversion. Observed photocurrent density from the nanorod device is more than two times higher than thin films fabricated under similar conditions, in spite of actual coverage for the nanorod device being 12% compared to the thin film. In addition to improved photocurrent generation, reduced material consumption due to enhanced effectiveness at lower coverage and simplicity of the fabrication technique makes this process ideal for the cost-effective production of high efficiency solar cells at commercial scale. (C) 2014 Elsevier B.V. All rights reserved.