Physical vapor deposition of Yb-doped CsPbCl3 thin films for quantum cutting

Ytterbium-doped CsPbCl${}_{3}$ emerges as the primary contender for a quantum cutting coating on silicon solar cells, aiming to enhance both their efficiencies and durability. This is accomplished by converting each incident ultraviolet and blue photon with energies greater than 2.5 eV into two 1.25 eV near-infrared red photons. The potential of this approach lies in the possibility of surpassing the Quessier limit, thereby augmenting the efficiencies of silicon solar cells. While thin films produced through colloidal synthesis and nanocrystal dispersions have demonstrated photoluminescence quantum yields nearing 200%, there has been a growing interest in employing physical vapor deposition as a large-area scalable method due to sub-band gap absorption exhibited by colloidal films. In the present study, the authors made an intriguing discovery regarding the significant influence of post-deposition annealing environment and protocols on the near-infrared photoluminescence quantum yields in Yb-doped halide perovskite films that demonstrate the downconversion of ultraviolet and blue light through quantum cutting.