Nanostructured Silicon Photocathodes for Solar Water Splitting Patterned by the Self-Assembly of Lamellar Block Copolymers

By Lang Shen and Chunlin He and Jing Qiu and Sung-Min Lee and Abinasha Kalita and Stephen B. Cronin and Mark P. Stoykovich and Jongseung Yoon
Published in ACS Applied Materials & Interfaces NULL 2015

Abstract

We studied a type of nanostructured silicon photocathode for solar water splitting, where one-dimensionally periodic lamellar nanopatterns derived from the self-assembly of symmetric poly(styrene-block-methyl methacrylate) block copolymers were incorporated on the surface of single-crystalline silicon in configurations with and without a buried metallurgical junction. The resulting nanostructured silicon photocathodes with the characteristic lamellar morphology provided suppressed front-surface reflection and increased surface area, which collectively contributed to the enhanced photocatalytic performance in the hydrogen evolution reaction. The augmented light absorption in the nanostructured silicon directly translated to the increase of the saturation current density, while the onset potential decreased with the etching depth because of the increased levels of surface recombination. The pp+-silicon photocathodes, compared to the n+pp+-silicon with a buried solid-state junction, exhibited a more pronounced shift of the current density

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