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 (η_int) 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 η_int of 118.1 ± 6.7% that is 2-fold higher than previous records using Mn²⁺-doped quantum dots (QDs). If using CsPbCl_xBr_3–x NCs capable of absorbing ∼7.6% of solar photons, the projected external optical efficiency (η_ext) 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.