Abstract Lead toxicity and instability both are the big concern for the utilization of lead halide perovskites. To defeat this challenge, we synthesized lead free Zn based all inorganic mixed halide 2D perovskite Cs2ZnX4 (X = Cl4, Cl2Br2 and Cl2I2) nanocrystals (PNCs) first time with high photoluminescence quantum yield of 51.93%. Perovskite NCs were synthesized by using ligand-assisted re-precipitation (LARP) technique at 80 °C with the pH = 8.4 of reaction solution. The formation of Cs2ZnCl4, Cs2ZnBr2Cl2 and Cs2ZnCl2I2 NCs was discussed in details. We have observed tenability of their optical band gap from 3.68 to 3.54 eV. These blue fluorescent NCs displayed morphological change from hexagonal to quasi-spherical and maintained their excellent stability over six months. The as-prepared NCs were characterized by using UV–vis, PL, XRD, TEM, FE-SEM, EDS, TCSPC, Raman, FT-IR, XPS and TGA analytical techniques.

中文翻译：

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高度稳定的蓝色荧光无铅全无机 Cs2ZnX4 2D 钙钛矿纳米晶体

摘要 铅的毒性和不稳定性是卤化铅钙钛矿利用的主要问题。为了克服这一挑战，我们首次合成了无铅锌基全无机混合卤化物二维钙钛矿 Cs2ZnX4（X = Cl4、Cl2Br2 和 Cl2I2）纳米晶体 (PNCs)，其光致发光量子产率高达 51.93%。通过使用配体辅助再沉淀 (LARP) 技术在 80 °C 和 pH = 8.4 的反应溶液中合成钙钛矿 NC。详细讨论了 Cs2ZnCl4、Cs2ZnBr2Cl2 和 Cs2ZnCl2I2 NCs 的形成。我们已经观察到它们的光学带隙从 3.68 到 3.54 eV 的稳定性。这些蓝色荧光 NCs 表现出从六边形到准球形的形态变化，并在六个月内保持了出色的稳定性。通过使用 UV-vis、PL、XRD、TEM、FE-SEM、