Although many synthetic methods such as hot injection and anionic exchange can produce full-color perovskite nanocrystals (PNCs), their emission spectra are broadened by compositional non-uniformity. Here, we propose the synthetic method, hydrogen halide (HX; X = Cl, Br, and I)-mediated uniform halide anion exchange at mild temperatures, for high color-purity PNCs emitters across the full-color spectrum. The HX-mediated exchange reaction produces high-purity PNCs without metallic Pb impurities due to the use of volatile HX as the X source. The blue, green, and red PNCs show narrow emission spectra, with 16, 18, and 18.5 nm of full width at half-maximum, respectively. The red PNC emitter synthesized by the HX-mediated method has a single photoluminescent (PL) peak, with a narrow emission spectrum at low temperature due to compositional uniformity, whereas the PNCs produced by other methods have multiple PL peaks. Accordingly, the red/green/blue electroluminescent devices also have narrow emission spectra.

尽管许多合成方法（例如热注射和阴离子交换）可以产生全色钙钛矿纳米晶体（PNC），但其发射光谱由于组成不均匀而变宽。在这里，我们提出了一种合成方法，在温和的温度下，卤化氢（HX； X = Cl，Br和I）介导的均匀卤化物阴离子交换，适用于整个色谱范围内的高色纯度PNC发射体。由于使用挥发性HX作为X源，HX介导的交换反应产生了高纯度的PNC，而没有金属Pb杂质。蓝色，绿色和红色PNC的发射光谱较窄，半峰全宽分别为16、18和18.5 nm。通过HX介导的方法合成的红色PNC发射器具有一个光致发光（PL）峰，由于组成均匀性，在低温下其发射光谱较窄，而通过其他方法生产的PNC具有多个PL峰。因此，红色/绿色/蓝色电致发光器件也具有窄的发射光谱。