TiO2-coated upconverting NaGdFxOy: Yb/Er Hollow Sphere for High Performance Dye-Sensitized Solar Cells

摘要

Dye-sensitized solar cells (DSSCs) have received great attention due to its advantageous characteristics, such as low cost, environmental benignity, high conversion efficiency. However, the dye adsorption range in DSSCs is very limited. For example, a widely used N719 can only adsorb the light from 300 nm to 800 nm. Clearly, most of infrared light in the solar spectrum is not utilized. It is well known that upconversion material NaGdF4:Yb Er absorbs the NIR photons and emits green and red light; the corresponding wavelengths of emitted light are 500nm and 660nm, respectively, under 980-nm diode laser irradiation[1, 2], which matches the absorption spectrum of N719 dye. To this end, much research[3-8] has been performed to introduce different shapes of upconversion materials, including sub-microprisms[3], nanoparticles[4], nanorod[8], nanoplates[9], and the other shape[5-7], into the photoanode of dye-sensitized solar cells to improve the overall power conversion efficiency. However, reports on the introduction of hollow upconversion materials into the photoanode are very limited.