Balestrieri Matteo, Colis Silviu, Gallart Mathieu, Schmerber Guy, Bazylewski Paul, Chang Gap Soo, Ziegler Marc, Gilliot Pierre, Slaoui Abdelilah, Dinia Aziz
Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, B.P. 43, F-67034 Strasbourg Cedex 2, France.
Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, SK S7N 5E2, Canada.
Phys Chem Chem Phys. 2016 Jan 28;18(4):2527-34. doi: 10.1039/c5cp04961j.
CeO2 is a promising material for applications in optoelectronics and photovoltaics due to its large band gap and values of the refractive index and lattice parameters, which are suitable for silicon-based devices. In this study, we show that trivalent Sm, Nd and Yb ions can be successfully inserted and optically activated in CeO2 films grown at a relatively low deposition temperature (400 °C), which is compatible with inorganic photovoltaics. CeO2 thin films can therefore be efficiently functionalized with photon-management properties by doping with trivalent rare earth (RE) ions. Structural and optical analyses provide details of the electronic level structure of the films and of their energy transfer mechanisms. In particular, we give evidence of the existence of an absorption band centered at 350 nm from which energy transfer to rare earth ions occurs. The transfer mechanisms can be completely explained only by considering the spontaneous migration of Ce(3+) ions in CeO2 at a short distance from the RE(3+) ions. The strong absorption cross section of the f-d transitions in Ce(3+) ions efficiently intercepts the UV photons of the solar spectrum and therefore strongly increases the potential of these layers as downshifters and downconverters.
由于二氧化铈（CeO₂）具有较大的带隙、折射率和晶格参数值，适合用于硅基器件，因此它是一种在光电子学和光伏领域具有应用前景的材料。在本研究中，我们表明三价钐（Sm）、钕（Nd）和镱（Yb）离子能够成功插入到在相对较低沉积温度（400°C）下生长的CeO₂薄膜中并实现光学激活，这与无机光伏技术兼容。因此，通过掺杂三价稀土（RE）离子，CeO₂薄膜可以有效地实现具有光子管理特性的功能化。结构和光学分析提供了薄膜电子能级结构及其能量转移机制的详细信息。特别是，我们证明了存在一个以350nm为中心的吸收带，能量从该吸收带转移到稀土离子。只有考虑Ce(3+)离子在CeO₂中在距RE(3+)离子短距离处的自发迁移，才能完全解释转移机制。Ce(3+)离子中f-d跃迁的强吸收截面有效地截获了太阳光谱中的紫外光子，因此极大地提高了这些层作为下转换和下转换层的潜力。
