Synthesis and characteristics of the nano-scaled YBO₃:sm³⁺ phosphors applied to improve the efficiency of solar cells

The reddish orange phosphor with nanostructure is proposed to improve the efficiency of solar cells in this research. According to the absorption spectrum of c-Si solar cell, only the light with wavelength less than 1000 nm can be absorbed, and the strongest absorption band locates during wavelengths 500 to 900 nm. Ultraviolet (UV) light with high energy photons can be absorbed by solar cells as well, but the most energy is converted into heat and this phenomenon results in the lower efficiency. The YBO₃:Sm³⁺ nano-phosphor with emission bands locating at 570, 610 and 655 nm is proposed to convert UV light into reddish orange light absorbed by solar cells. By means of this scheme, the converting efficiency of solar cells can be improved. The nano-scaled YBO₃:Sm³⁺ phosphor was obtained by the chemical co-precipitation method and thermal treatments. The average diameter of particles is about 60 nm. From the PLE spectrum, this phosphor can be stimulated strongly by light with wavelength locating at 405 nm and emit the light bands locating at 570, 610 and 655 nm. This three emission bands originate from the following electron transitions ⁴G_5/2 → ⁶H_5/2, ⁴G_5/2 → ⁶H_7/2, and ⁴G_5/2 → ⁶H_9/2, respectively. In our experiments, the YBO₃ phosphor with 1% dopant Sm³⁺ possesses the optimal emission efficiency and can be applied to improve the converting efficiency of solar cells.