Identifying champion nanostructures for solar water-splitting

• Published in: Nature materials Vol. 12; no. 9; pp. 842 - 849
• Main Authors: Warren, Scott C., Voïtchovsky, Kislon, Dotan, Hen, Leroy, Celine M., Cornuz, Maurin, Stellacci, Francesco, Hébert, Cécile, Rothschild, Avner, Grätzel, Michael
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2013; Nature Publishing Group
• Subjects: 639/301/119/544; 639/301/299/1013; 639/301/299/161; 639/301/357; 639/301/357/354; 639/301/357/995; 639/638/439; Aggregates; Air masses; Biomaterials; Charge transport; Condensed Matter Physics; Correlation; Electrodes; Energy conversion; Materials Science; Metal oxides; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Models, Theoretical; Nanoparticles; Nanostructure; Nanostructures - chemistry; Nanotechnology; Optical and Electronic Materials; Photochemical Processes; Photocurrent; Solar Energy; Spatial distribution; Sunlight; Surface Properties; Water - chemistry
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3684

Charge transport in nanoparticle-based materials underlies many emerging energy-conversion technologies, yet assessing the impact of nanometre-scale structure on charge transport across micrometre-scale distances remains a challenge. Here we develop an approach for correlating the spatial distribution of crystalline and current-carrying domains in entire nanoparticle aggregates. We apply this approach to nanoparticle-based α-Fe 2 O 3 electrodes that are of interest in solar-to-hydrogen energy conversion. In correlating structure and charge transport with nanometre resolution across micrometre-scale distances, we have identified the existence of champion nanoparticle aggregates that are most responsible for the high photoelectrochemical activity of the present electrodes. Indeed, when electrodes are fabricated with a high proportion of these champion nanostructures, the electrodes achieve the highest photocurrent of any metal oxide photoanode for photoelectrochemical water-splitting under 100 mW cm −2 air mass 1.5 global sunlight. Assessing the effect of nanometre-scale structure on charge transport across micrometre-scale distances remains a fundamental challenge for many energy-conversion technologies. By correlating the structure and the charge transport with nanometre resolution across micrometre-scale distances, nanoparticle aggregates responsible for the high photoelectrochemical water-splitting activity of α-Fe 2 O 3 electrodes are identified.