Synthesis and characterization of NaYF4: Yb, Er nanoparticles with efficient up-conversion fluorescence based on new type solar cells

An up-converting material, which can be efficiently excited by near infrared light and emit strong visible light through a process termed dasiaup-conversion fluorescencepsila, has shown great potential for use in silicon thin films solar cells. This kind of material when placed on the rear side of p-i-n type silicon thin films solar cells will increase the overall efficiency of the PV device by utilizing sub-band gap photons that would otherwise be transmitted through the device. Sodium yttrium fluoride (NaYF₄) up-converting nanoparticles doped with lanthanide ions have been synthesized. Different lanthanide ions (Yb³⁺, Er³⁺) were doped into the nanoparticles, which showed strong up-conversion fluorescence under excitation at 980 nm. Above reason comes from that intensity of the hexagonal nanocrystals in this work is much higher than that of other cubic-phase NaYF₄ nanocrystals. In addition, the nanoparticles showed a spherical shape with an average size of about 50 nm.