Enhanced Photoluminescence of Dual Mn(II)-Based All-Inorganic Perovskite Nanocrystals Via Ce3+ Doping for White Light-Emitting Diodes and Anti-Counterfeiting

Lead-free all-inorganic Mn(II)-based perovskite nanocrystals, featuring low toxicity and broadband emission, serve as ideal candidates for white light-emitting diodes (WLEDs) and anti-counterfeiting devices. However, their practical applications are severely restricted by the relatively low photoluminescence quantum yield (PLQY). Herein, a Ce3+ doping strategy was adopted in this work to modulate the optical properties of two types of Mn (II)-based perovskite nanocrystals, namely CsMnCl3 with a trimeric chain structure and Cs2MnCl4 with a layered structure. By partially substituting Mn2+ with Ce3+ ions, the surface defects of the nanocrystals are effectively passivated, resulting in a remarkable enhancement in PLQY. Specifically, the PLQY of green-emitting Cs2MnCl4 nanocrystals increases from 26.70% to 67.14%, while that of red-emitting CsMnCl3 nanocrystals rises from 36.38% to 68.19%. A WLED device is fabricated by integrating the two Ce3+-doped nanocrystals with a 460 nm blue LED chip and exhibits a chromaticity coordinate of (0.332, 0.334), which is highly close to that of standard white light, with a correlated color temperature of 5978 K and a high color rendering index of 87.6. The excitation-dependent photoluminescent properties further endow them with the potential in anti-counterfeiting. This work provides an effective defect-passivation strategy for Mn(II)-based perovskite nanocrystals, paving the way in solid-state lighting and anti-counterfeiting technologies.