Enhanced Power Conversion Efficiency of Perovskite Solar Cells with an Up-Conversion Material of Er(3+)-Yb(3+)-Li(+) Tri-doped TiO(2)

In this paper, Er(3+)-Yb(3+)-Li(+) tri-doped TiO(2) (UC-TiO(2)) was prepared by an addition of Li(+) to Er(3+)-Yb(3+) co-doped TiO(2). The UC-TiO(2) presented an enhanced up-conversion emission compared with Er(3+)-Yb(3+) co-doped TiO(2). The UC-TiO(2) was applied to the perovskite solar cells. The power conversion efficiency (PCE) of the solar cells without UC-TiO(2) was 14.0%, while the PCE of the solar cells with UC-TiO(2) was increased to 16.5%, which presented an increase of 19%. The results suggested that UC-TiO(2) is an effective up-conversion material. And this study provided a route to expand the spectral absorption of perovskite solar cells from visible light to near-infrared using up-conversion materials. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s11671-018-2545-y) contains supplementary material, which is available to authorized users.