Tailoring the upconversion of ABF3:Yb3+/Er3+ through Mn2+ doping

Abstract

Successful upconversion (UC) tuning from multi-bands to one single red band from Er³⁺ ions was realized in cubic perovskite ABF₃:Yb³⁺/Er³⁺ (A = K, Cs; B = Zn, Cd) through Mn²⁺ doping. Based on UC emission spectra and decay kinetics of KZnF₃:Yb³⁺/Er³⁺ with different Mn²⁺ contents, a bidirectional energy transfer process between Mn²⁺ and Er³⁺ ions was confirmed to explain the UC tuning mechanism. More importantly, we studied the influence of the Mn²⁺ energy level position on the UC properties for Er³⁺ in ABF₃ hosts. Interestingly, great enhancement of green UC emissions was observed for Er³⁺ ions in KCdF₃ and CsCdF₃ hosts upon Mn²⁺ doping. Comparison of UC emissions and lifetimes of Er³⁺ ions in the three materials was carried out to probe the different UC processes in ABF₃ (A = K, Cs; B = Zn, Cd) hosts. The different energy transfer mechanism between Mn²⁺ and Er³⁺, which is affected by the Mn²⁺ energy level position, was proposed to explain the UC difference in the three matrices. This research convincingly confirmed the occurrence of energy transfer between Er³⁺ and Mn²⁺ ions and provided deep insights into the importance of the Mn²⁺ energy level position in tuning the UC properties of Er³⁺ in diverse hosts, while allowing us to better control the UC properties through Mn²⁺ doping.