Cooperative energy acceptor of three Yb3+ ions

• Published in: Journal of rare earths Vol. 36; no. 5; pp. 461 - 467
• Main Authors: Guo, Junjie, Di, Weihua, Aidilibike, Tuerxun, Li, Yangyang, Liu, Xiaohui, Qin, Weiping
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2018
• Subjects: Ce3+-Yb3; Cooperative acceptor; Quantum cutting; Rare earths; Solar cells; Yb3+-trimer; Solar cells; Ce3+-Yb3; Quantum cutting; Cooperative acceptor; Rare earths; Yb3+-trimer
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2017.10.001

Our previous work first reported the cooperative sensitized luminescence from Cu2+ or Pb2+ by three clustered Yb3+ ions, in which three NIR photons can be converted into a high energy photon. Could a reverse process happen that a high energy photon is cut into three NIR photons? This work demonstrated an example of three-photon quantum cutting (QC) phosphor, CaF2:Ce3+,Yb3+, in which three clustered Yb3+ ions (Yb3+-trimer) cooperatively and indirectly received a 306 nm ultraviolet (UV) photon energy transferred from a Ce3+ ion in 5d excited state and emitted three 975 nm near-infrared (NIR) photons. The cluster destruction experiments were designed to verify the necessity of the presence of Yb3+-trimers for QC. The dynamical analysis on luminescence of Ce3+ ions confirmed the energy transfer from Ce3+ ions to Yb3+-trimers. The doping concentration effect on luminescence was investigated. Furthermore, the maximum energy transfer (ET) efficiency and the corresponding QC efficiency were estimated to be 61% and 222%, respectively. Therefore, the reported three-photon QC phosphor has an attractive prospect in efficiently harvesting solar energy for silicon solar cells. [Display omitted] a. Downconversion emission spectrum (black line) and upconversion emission spectrum (red line) of CaF2:Yb3+, Ce3+, Na+ excited by 306 nm and 980 nm, respectively. b. Schematic energy level diagram of Yb3+ and Ce3+, as well as the proposed QC mechanisms under 306 nm excitation.