Thursday, November 10, 2016

Researchers at Lawrence Berkeley National Laboratory integrate water-splitting catalyst with a solar cell by PEALD

Meanwhile, a team of international researchers at Lawrence Berkeley National Laboratory have been very busy taking a major steps towards artificial photosystems employing PEALD processes performed at the Molecular Foundry at Berkeley Lab.

The CoOx catalyst films were deposited in a Oxford Instruments FlexAL PEALD reactor using CoCp2 (98% Strem Chemicals) and oxygen plasma was the oxidant.

Schematic of the multi-functional water splitting catalyst layer engineered using atomic layer deposition for integration with a high-efficiency silicon cell. (Credit: Ian Sharp/Berkeley Lab)

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes [OPEN ACCESS]
Jinhui Yang, Jason K. Cooper, Francesca M. Toma,  Karl A. Walczak, Marco Favaro, Jeffrey W. Beeman, Lucas H. Hess,  Cheng Wang, Chenhui Zhu, Sheraz Gul, Junko Yano, Christian Kisielowski, Adam Schwartzberg & Ian D. Sharp
Nature Materials doi:10.1038/nmat4794
Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co3O4/Co(OH)2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co3O4 spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.