Quantum-Cutting Luminescent Solar Concentrators Using Ytterbium-Doped Perovskite Nanocrystals.

We introduce and demonstrate the concept of quantum-cutting luminescent solar concentrators (QC-LSCs) using Yb3+ -doped perovskite nanocrystals. These NCs feature a photoluminescence quantum yield approaching 200% and virtually zero self-absorption loss of PL photons, defining a new upper limit of 150% for the internal optical efficiency (ηint ) of LSCs that is almost independent of LSC sizes. An un-optimized 25 cm2 QC-LSC fabricated from Yb3+ -doped CsPbCl3 NCs already displayed an ηint of 118.1 ± 6.7% that is 2-fold higher than previous records using Mn2+ -doped quantum dots (QDs). If using CsPbCl x Br3- x NCs capable of absorbing ∼7.6% of solar photons, the projected external optical efficiency (ηext ) of QC-LSCs can exceed 10% for >100 cm2 devices, which still remains a challenge in the field. The advantage of QC-LSCs over conventional QD-LSCs becomes especially obvious with increasing LSC sizes, which is predicted to exhibit a more than 4-fold efficiency enhancement in the case of window-size (1 m2 ) devices.