Ultra-high photoluminescence quantum yield of Bi3+-doped Cs2ZrCl6 double perovskite micro-crystallites by thermal precipitation in ionic liquids

• Published in: Journal of luminescence 2024-05, Vol.269, p.120531, Article 120531
• Main Authors: Zhang, Guang-Xuan, Yin, Qiao-Yun, Wang, Bing, Liu, Li-Ying, Chang, Li-Yuan, Wang, Ru-Zhi
• Format: Article
• Language: English
• Subjects: Double perovskites; Ionic liquids; Passivation effect; PLQY
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2024.120531

All-inorganic lead-containing perovskites have shown strong luminescence, but the use of lead has hindered their commercial development due to its stability and toxicity. In this paper, we propose thermal precipitation in ionic liquids (ILs) for synthesizing Bi3+-doped Cs2ZrCl6 double perovskites (Cs2ZrCl6:Bi3+(ILs)), which have a better crystallinity compared to the Cs2ZrCl6:Bi3+ (HCl) synthesized by the traditional hydrochloric acid method. Most interestingly, the Cs2ZrCl6:Bi3+(ILs) exhibits ultra-high photoluminescence quantum yield (PLQY) of up to 78.52%, which is about three times higher than the Cs2ZrCl6:Bi3+ (HCl) prepared by the traditional method. In addition, the PLQY of this paper is the highest in the reported works for the Cs2ZrCl6:Bi3+. It has been confirmed that the high PLQY of Cs2ZrCl6:Bi3+(ILs) is due to the interaction force between N atoms and perovskites in ionic liquid cations, and the cations in ionic liquids can improve the crystallinity of Cs2ZrCl6:Bi3+(ILs) double perovskite crystallites by passivating shallow defects. The research provides an alternative and efficient method for synthesizing stable lead-free double perovskites with good optical properties. •Bi3+-doped Cs2ZrCl6 double perovskite materials were synthesized in ionic liquids by simple thermal precipitation.•The PLQY of Cs2ZrCl6:Bi3+ (ILs) was 78.52%, which was about 3 times that of Cs2ZrCl6:Bi3+ prepared under the HCl system.•The passivation mechanism for the enhanced optical properties of Cs2ZrCl6:Bi3+ by ionic liquid was proposed and verified.•This work provides an innovative strategy for improving the optical properties of all-inorganic lead-free perovskites.