A reliable TiO 2 nanotube membrane transfer method and its application in photovoltaic devices

Abstract

In this work we present a highly reproducible method to fabricate front-illuminated TiO 2 nanotube-based dye-sensitized solar-cell. The well oriented nature of the nanotube arrays ensures favorable electron percolation pathways for charge transfer between interfaces. Our two-step anodization approach allows for a nearly 100% reliable production of uniform films with a greater flexibility in the thickness of the nanotube membranes suitable for both liquid and solid electrolyte dye-sensitized solar-cells (DSCs). Large area nanotube membranes fabricated by this method were successfully detached and transferred onto fluorine-doped tin oxide (FTO) and other substrates without crack formation. In contrast to earlier methods, the method presented here does not require steps that may damage the nanotube membrane quality such as prolonged ultrasonication or acid treatment. We systematically study the current-time profile and analyze the detachment mechanism. Front-illuminated nanotube-based dye-sensitized solar-cells using this method reach an efficiency of 6.3% with liquid electrolytes (of which at least 6.1% originate from the transferred membrane) and 1.9% when using the solid state hole conductor CuSCN under AM1.5 1 sun illumination. © 2011 Elsevier Ltd.