Akkerman Quinten A, D'Innocenzo Valerio, Accornero Sara, Scarpellini Alice, Petrozza Annamaria, Prato Mirko, Manna Liberato
†Nanochemistry Department, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
‡Center for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, via Giovanni Pascoli 70/3, 20133 Milano, Italy.
J Am Chem Soc. 2015 Aug 19;137(32):10276-81. doi: 10.1021/jacs.5b05602. Epub 2015 Aug 6.
We demonstrate that, via controlled anion exchange reactions using a range of different halide precursors, we can finely tune the chemical composition and the optical properties of presynthesized colloidal cesium lead halide perovskite nanocrystals (NCs), from green emitting CsPbBr3 to bright emitters in any other region of the visible spectrum, and back, by displacement of Cl(-) or I(-) ions and reinsertion of Br(-) ions. This approach gives access to perovskite semiconductor NCs with both structural and optical qualities comparable to those of directly synthesized NCs. We also show that anion exchange is a dynamic process that takes place in solution between NCs. Therefore, by mixing solutions containing perovskite NCs emitting in different spectral ranges (due to different halide compositions) their mutual fast exchange dynamics leads to homogenization in their composition, resulting in NCs emitting in a narrow spectral region that is intermediate between those of the parent nanoparticles.
我们证明，通过使用一系列不同的卤化物前体进行可控的阴离子交换反应，我们可以精细地调节预合成的胶体铯铅卤化物钙钛矿纳米晶体（NCs）的化学成分和光学性质，从发射绿光的CsPbBr₃到可见光谱任何其他区域的明亮发射体，再通过Cl⁻或I⁻离子的置换以及Br⁻离子的重新插入变回绿光发射体。这种方法能够制备出结构和光学性质与直接合成的NCs相当的钙钛矿半导体NCs。我们还表明，阴离子交换是一个在NCs之间的溶液中发生的动态过程。因此，通过混合含有在不同光谱范围发射（由于卤化物组成不同）的钙钛矿NCs的溶液，它们相互之间快速的交换动力学导致其组成均匀化，从而产生在介于母体纳米颗粒发射光谱之间的窄光谱区域发射的NCs。
