UC spectra of NPs for all dopant compositions and photograph of pellets prepared from UCNPs. (a) UC spectra of Y1.97Yb0.02Er0.01O3 (green line), Y1.94Yb0.05Er0.01O3 (yellow line), and Y1.89Yb0.10Er0.01O3 (red line) NPs. (b) Photograph of pellets prepared from UCNPs with different Yb3+ concentrations taken under 978-nm excitation.
Lojpur et al. Nanoscale Research Letters 2013 8:131 doi:10.1186/1556-276X-8-131