Near Infrared Quantum Cutting Of Yb³⁺-Ln³⁺?Ln=Er,Pr,Sm? Codoped Oxide Host

Quantum Cutting?QC?can cut one high energy photon absorbed into two or more low-energy photon,which makes the quantum efficiency of luminescent material over than 100%,even up to 200%.The near-infrared?NIR?QC phosphors based on Yb³⁺–Ln³⁺?Ln = Tb,Pr,Tm,Ho and Ce?couple has become a focus in recent years,as the emission of Yb³⁺ ions is around 1000 nm and matches well with the band gap of crystalline Si,the QC phosphors which based on Yb³⁺–Ln³⁺ is believed to be possibly applied in Si-based solar cells as a solar spectrum modifier.As the oxides have better thermal and chemical stability,better mechanical strength,simple production process and environmental friendliness,oxide-based phosphors are believed to be more applicable in many fields.In this paper,we chose oxides SrMoO₄ and Y₂BaZnO₅ as host,doped with Yb³⁺-Pr³⁺/Sm³⁺ and Yb³⁺-Er³⁺,respectively.the NIR luminescent properties and mechanism of quantum cutting in oxides have been investigated.The content of this paper includes:1.Pr³⁺,Yb³⁺ and Sm³⁺,Yb³⁺ co-doped SrMoO₄ phosphors have been prepared via high temperature solid-state reaction method.The quantum cutting based on Sm³⁺,Yb³⁺ couple results in a new emission band at 1000 nm and the quantum cutting based on Pr³⁺,Yb³⁺ couple realizes a broad near-infrared emission of about 76 nm in full width at half maximum,centered at 1000 nm.Meanwhile the near infrared emission intensity for Sm³⁺,Yb³⁺ and Pr³⁺,Yb³⁺ co-doped SrMoO₄ phosphors have also been increased by 2.1 and1.8 times,with 36.5% and 9.6% energy transfer efficiencies from Sm³⁺to Yb³⁺and Pr³⁺to Yb³⁺,respectively.The result provides a meaningful reference for designing broad-band near infrared phosphors or tunable near infrared laser materials.2.Er³⁺-Yb³⁺co-doped Y₂BaZnO₅ phosphors were synthesized via high temperature solid-state reaction method.The quantum cutting properties for Er³⁺-Yb³⁺ co-doped Y2 Ba ZnO5 phosphors have been detailedly exploited under different wavelength excitation.Unlike in fluoride host,only the Er³⁺?4S3/2?+ Yb³⁺?2F7/2?? Er³⁺?4I13/2?+Yb³⁺?2F5/2?energy transfer process in Y2 Ba ZnO5 effectively performs the down-conversion,which can split an absorbed high-energy photon into two photons of1000 nm and 1550 nm radiation,and when phosphors give the strongest emissions in the near infrared region,the energy transfer efficiencies from Er³⁺ to Yb³⁺ is up to 54%.The quantum cutting properties of Er³⁺-Yb³⁺ couple in Y₂BaZnO₅ provides meaningful reference in search of new efficient Er³⁺-Yb³⁺co-doped quantum cutting phosphors.