Near-infrared emitting colloidal solution of nanocrystals for multi-band optical amplification

We report on a strategy to realize simultaneous and efficient multi-band near-infrared (NIR) emission from Pr3+, Tm3+ and Er3+ that covers almost the entire optical communication wavelength region (from O to U band) by employing a nanocrystal-solvent colloidal system. The NIR emission spectra and fluorescent decay curves of different colloidal systems are investigated and compared. The results indicated that interaction among different RE ions that lead to quenching of the NIR emission could be effectively inhibited by solutions containing NCs doped with three different ion pairs (Yb3+-Pr3+, Yb3+-Tm3+ and Yb3+-Er3+) separately. The mechanism of this phenomenon is also discussed. This strategy may have potential applications in multi-band optical amplifiers for the optical communication window.