Absolute Upconversion Quantum Yield of β-NaYF4:Er3+ under Broadband Excitation in Dependence on the Erbium Concentration – Measurements and Simulations

We investigate the upconversion quantum yield of β-NaYF4:Er3+ under broadband excitation both experimentally and theoretically. The upconversion quantum yield strongly depends on the erbium concentration, and shows a maximum for an erbium concentration of 25%.