Strong violet emission from ultra-stable strontium-doped CsPbCl3 superlattices

Yongqiang Ji; Minqiang Wang; Zhi Yang; Hao Wang; Muhammad Amin Padhiar; Hengwei Qiu; Jialin Dang; Yinru Miao; Yun Zhou; Arshad Saleem Bhatti

doi:10.1039/d1nr07848h

Strong violet emission from ultra-stable strontium-doped CsPbCl₃ superlattices

Nanoscale. 2022 Feb 10;14(6):2359-2366. doi: 10.1039/d1nr07848h.

Authors

Affiliations

¹ Electronic Materials Research Laboratory (EMRL), Key Laboratory of Education Ministry, International Center for Dielectric Research (ICDR), Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic and Information Engineering, Xi'an Jiaotong University, 710049 Xi'an, China. mqwang@xjtu.edu.cn.
² State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, China.
³ Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 100084, China.
⁴ Centre for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad, 44500, Pakistan.

PMID: 35088791
DOI: 10.1039/d1nr07848h

Abstract

Among the lead halide perovskites, the photoluminescence quantum yields (PLQYs) of perovskite quantum dots (PQDs) in the violet region are the very lowest. This is an obstacle to the optical applications across the entire visible area based on perovskite materials. Herein, we report a novel strontium (Sr)-substitution along with chlorine passivation strategy to enhance the PLQYs of CsPbCl₃ PQDs. We surprisingly found that when the molar ratio of Sr²⁺/Pb²⁺ = 0.1/0.9, CsSr_0.1Pb_0.9Cl₃ PQDs exhibit strong single-color violet emission, which is attributed to the effective passivation of chlorine defects. We further found spontaneous self-assembly of PQDs into highly emissive PSCs from the precursor in a highly concentrated solution. Moreover, by dilution of these PSCs, a few small PQD aggregates can be regained, which is similar to the PQDs formed at lower concentrations. Benefiting from the superior collective properties of individual PQDs, these highly fluorescent CsSr_0.1Pb_0.9Cl₃ PSCs can maintain good stability even when directly immersed in water or exposed to illumination.