Boosting the Photoluminescence Quantum Yield and Stability of Lead-Free CsEuCl₃ Nanocrystals via Ni²⁺ Doping

Abstract

Colloidal CsPbX3 (X = Br, Cl, or I) perovskite nanocrystals (PNCs) have emerged as low-cost, high-performance light-emitting materials, whereas the toxicity of lead limits their applications. Europium halide perovskites offer promising alternatives to lead-based perovskites due to their narrow spectral width and high monochromaticity. Nonetheless, the photoluminescence quantum yields (PLQYs) of CsEuCl3 PNCs have been very low (∼2%). Herein, Ni2+-doped CsEuCl3 PNCs have been first reported, exhibiting bright blue emission centered at 430.6 ± 0.6 nm with a full width at half-maximum of 23.5 ± 0.3 nm and a PLQY of 19.7 ± 0.4%. To the best of our knowledge, this is the highest PLQY value reported for CsEuCl3 PNCs so far, an order of magnitude higher than in previous work. DFT calculations demonstrate that Ni2+ enhances PLQY by concurrently increasing the oscillator strength and removing Eu3+ which hinders the photorecombination process. B-site doping offers a promising approach to enhance the performance of lanthanide-based lead-free PNCs.

High-entropy alloy screening for halide perovskites

“…, CsPbI 3 's metastable polymorphs). 1,2 There are more reports of single-phase inorganic HEAHP (Table S4, ESI†) 71–219 and hybrid organic–inorganic HEAHP (Table S5, ESI†), 220–285 but more investigation into single-phase boundaries is needed to confirm the broadscale applicability of UCV for screening HEAHP.…”

Bright Blue Emission Lead-Free Halides with Narrow Bandwidth Enabled by Oversaturated Europium Doping

“…After that, efforts have been made to improve the PLQY of CsEuCl 3 NCs. Zhang’s group reported the photoluminescence enhancement of CsEuCl 3 NCs by Ni 2+ doping . Gamelin’s group demonstrated that internal defects, such as Eu Cs and Eu i , were the dominant nonradiative defects in CsEuCl 3 NCs, suggesting that further improvements of their PLQY should focus on the passivation of internal defects .…”