A New Up-conversion Material of Ho(3+)-Yb(3+)-Mg(2+) Tri-doped TiO(2) and Its Applications to Perovskite Solar Cells

A new up-conversion nanomaterial of Ho(3+)-Yb(3+)-Mg(2+) tri-doped TiO(2) (UC-Mg-TiO(2)) was designed and synthesized with a sol-gel method. The UC-Mg-TiO(2) presented enhanced up-conversion fluorescence by an addition of Mg(2+). The UC-Mg-TiO(2) was utilized to fabricate perovskite solar cells by forming a thin layer on the electron transfer layer. The results display that the power conversion efficiency of the solar cells based on the electron transfer layer with UC-Mg-TiO(2) is improved to 16.3 from 15.2% for those without UC-Mg-TiO(2). It is demonstrated that the synthesized UC-Mg-TiO(2) can convert the near-infrared light to visible light that perovskite film can absorb to improve the power conversion efficiency of the devices. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s11671-018-2681-4) contains supplementary material, which is available to authorized users.