Synergic effects of upconversion nanoparticles NaYbF4:Ho3+ and ZrO2 enhanced the efficiency in hole-conductor-free perovskite solar cells

Abstract

Extending the spectral absorption of organic–inorganic mixed-cation perovskite solar cells (PSCs) from visible light to the near-infrared (NIR) range minimizes the nonabsorption loss of solar photons. Few studies have focused on the application of high-fluorescence NaYbF₄:Ho³⁺ upconversion nanoparticles (UCNPs) in solar cells. In this study, NaYbF₄:Ho³⁺ UCNPs were successfully prepared using a solvothermal method. We incorporated the NaYbF₄:Ho³⁺ UCNPs into ZrO₂ as the scaffold layer for FA_0.4MA_0.6PbI₃ perovskite solar cells. This design enabled the dual-functional effects, that is, the harvesting of NIR light and its conversion to visible light and the reduction of the electron–hole recombination rate. The effect of different amounts of NaYbF₄:Ho³⁺ UCNPs on the device performance was investigated in detail. The best-performance devices based on optimized addition of UCNPs (40 wt%) could achieve a power conversion efficiency as high as 14.32%, an increase of 28.8% compared with conventional ZrO₂ nanoparticle-based PSCs (11.12%). The design of the synergetic operation of UCNPs and ZrO₂ in the mesoporous structure of PSCs enhanced the photocurrent and photovoltage. The results offered the flexibility for the device architecture and broaden the solar spectral use of UCNP-based devices.