GaPSb/Si photoelectrode for Solar Fuel Production
Résumé
Solar water splitting consists in the production of hydrogen fuel by photoelectrochemical (PEC) reactions. It offers a clean, environmentally friendly solution to sustain the global energy supply and has driven many researches recently [1-2]. Efficient solar water splitting demands suitable photoelectrodes, which should enable high light absorption and feature a band gap with appropriate band alignment to realize charge transfer from the photoelectrode to water. In this work, we investigate the potential of a new photoelectrode material GaPSb/Si for solar water splitting. Relaxed GaPSb monocrystalline alloy was grown on cheap silicon substrate by molecular beam epitaxy (MBE) without any evidence of phase separation. The band structure of GaPSb/Si is determined by combining experimental optical measurements with tight binding (TB) theoretical calculations, confirming the appropriate band alignment for water splitting. Moreover, PEC characterizations were carried out on different GaPSb/Si samples, demonstrating good PEC performances. GaPSb/Si thus appears as a promising candidate for low-cost high-efficiency solar water splitting.
[1] D. Kang, T. W. Kim, S. R. Kubota, A. C. Cardiel, H. G. Cha, K.-S. Choi, Chemical reviews 2015, 115, 12839.
[2] I. Lucci, S. Charbonnier, M. Vallet, P. Turban, Y. Léger, T. Rohel, N. Bertru, A. Létoublon, J.-B. Rodriguez, L. Cerutti, E. Tournié, A. Ponchet, G. Patriarche, L. Pedesseau, C. Cornet, Advanced Functional Materials 2018, 28, 1801585.