Luminescence behaviors and infrared-to-visible energy conversion in Er3+/Yb3+ -doped CaZr4O9 phosphors

Abstract Phosphor powders of CaZr 4 O 9 :Er 3+ and CaZr 4 O 9 :Er 3+ ,Yb 3+ were prepared by the urea combustion route. The crystal structure was characterized by powder XRD measurement. The optical properties were studied using absorption and photoluminescence (PL) spectroscopy. Upon excitation at 978 nm, the upconversion (UC) luminescence properties of Er 3+ and Er 3+ ,Yb 3+ co-doped CaZr 4 O 9 phosphors were analyzed. Energy transfer mechanism was discussed to understand the UC luminescence process for the Er 3+ and Er 3+ ,Yb 3+ co-doped CaZr 4 O 9 phosphors. From the pump power dependent green and red luminescence intensity analysis, required number of photons to populate the excited emitting levels are estimated and observed that the green emission intensity exhibits faster increase rates than red emission as a function of pump power. Upon excitation at 978 nm, the UC mechanism was discussed in terms of the experimental results.