(471c) Anode Assembly and Templating Strategies for Improving Efficiency and Versatility of Dye-Sensitized Solar Cells

The operation and efficiency of dye-sensitized solar cells (DSSCs) are inextricably linked to both light and charge transport/management.  Efforts to realize higher overall device efficiencies are confounded, in part, by challenges associated with the multicomponent nature of DSSCs.  Small incremental improvements in device efficiency since the pioneering work by Grätzel [1] nearly a decade ago motivate comprehensive optimization efforts spanning molecular engineering of novel dye sensitizers to materials engineering and component integration.  In this talk, we will describe efforts aimed at engineering anode microstructure in order to control and manage light transport without sacrificing conductivity or critical dye sensitization.  This is accomplished by embedding convex and concave microlenses at the interface of the conductive glass and porous, nanostructured titania anode via convective particle deposition and sacrificial templating, respectively.  The result is anode-embedded, ordered arrays of colloidal particles or concave replica structures that lead to enhancements in measured device efficiencies by as much as 28%.  The convective assembly strategy enables systematic variation of microlens properties (e.g., coordination, composition, size, location), and provides a handle for tuning anode morphology and even assembling anode structures on flexible, conductive substrates.  We will describe various fundamental studies of how modes of photon capture and distribution can be facilitated by embedded microlenses, how such light management translates to improvements in cell efficiency, and how progress towards realization of more versatile flexible devices can be realized. 

[1] O’Regan, Grätzel, Nature, 353 (1991).