Energy transfer in CaYAlO4: Ce3+, Pr3+ for sensitization of quantum-cutting with the Pr3+-Yb3+ couple

Silicon based solar cells show a poor yield in the UV-blue range of the solar spectrum. The thermalization of the charge carriers is one major loss mechanism, which could be overcome by depositing a quantum-cutting material in front of the solar cell. This phenomenon has recently been demonstrated in materials doped with the rare-earth couple Pr3+-Yb3+, where Pr3+ is able to sensitize two Yb3+ ion for one absorbed blue photon. Unfortunately, the weak absorption cross-section of Pr3+ ion makes it not suitable for thin films applications. Therefore, it is necessary to sensitize it to obtain a significant light yield. In that respect, Ce3+ ion could be used as a sensitizer of Pr3+ because its 4f-5d transition shows a high cross-section absorption. The purpose of this article is to study energy transfers between Ce3+ and Pr3+ in CaYAlO4 with a view to evaluate the potential of Ce3+ as a sensitizer of quantum-cutting with Pr3+-Yb3+ couple. We present results obtained in the bulk material and in a thin film dep...