TOP-Zn Steric Hindrance Effect Enables Ultra-Uniform CsPbX₃ Quantum Dots for Wide-Color Gamut Displays.

Abstract

Perovskite quantum dots (PQDs) are expected to be an ideal candidate for wide-color gamut displays owing to their high color purity. However, their color purity is challenged by remarkable spectral broadening due to non-uniform size distribution and crystal defects. Here, a ligand-ion (TOP-Zn) complex-modulating nucleation strategy is proposed to depress spectral broadening. This is achieved by enhancing the steric hindrance effect during lead-halogen octahedral assembly and reducing the reaction activity/sites of the system. This strategy is universal and has been confirmed to be effective for blue, green, and red PQDs, achieving narrowed spectral full-width-at-half-maximum (FWHM) of 15, 17, and 25 nm, respectively. These FWHMs are record-breaking and contribute to a wide color gamut coverage of ≈130% National Television Standards Committee and ≈100% Rec. 2020 standard. Meanwhile, these PQD-based light-emitting diodes (PeLEDs) exhibit a high external quantum efficiency (EQE) of exceeding 20% at their pure color range. These results provide a feasible path to achieve ultra-uniform and pure-color luminescent PQDs for wide-color gamut displays.