Infrared to visible upconversion luminescence in Er3+/Yb3+ co-doped CeO2 inverse opal

• UC emission of Er3+ was modified by introducing the structure of inverse opal.
• Color tuning of CeO2:Yb, Er inverse opal was realized by inhibition of UC emission.
• Two-photon excitation processes were observed in CeO2:Yb, Er inverse opal.

Infrared to visible upconversion luminescence has been investigated in Er3+/Yb3+ co-doped CeO2 inverse opal. Under the excitation of 980 nm diode lasers, visible emissions centered at 525, 547, 561, 660 and 680 nm are observed, which are assigned to the Er3+ transitions of 2H11/2 → 4I15/2 (525 nm), 4S3/2 → 4I15/2 (547, 561 nm), 4F9/2 → 4I15/2 (660 and 680 nm), respectively. The effect of photonic band gap on the upconversion luminescence intensity was also obtained. Additionally, the upconversion luminescence mechanism was studied. The dependence of Er3+ upconversion emission intensity on pump power reveals that it is a two-photon excitation process.