Synergistic Path for Dual Anisotropic and Electrically Switchable Emission From a Nanocomposite of CsPbBr₃ Quantum Cuboids and Nematic Liquid Crystal

Abstract

We report photophysical properties of a nanocomposite consisting of perovskite quantum cuboids (QCs) formed by CsPbBr3 and a wide temperature range nematic liquid crystal. Contrary to observations made with conventional II-VI quantum dots dispersed in a liquid crystal, the used QCs form, under the influence of the nematic orientation, linear assemblies over macroscopic length scales evidenced by polarizing optical microscopy. Interestingly, the linear assembly is actually caused by such an anisotropic arrangement at the nm scale, as seen in TEM images. Thin films of the nanocomposite exhibiting this unique and fascinating character exhibit absorption and emission features, which are quite appealing. These include retention of the sharp bandwidth of emission characteristic of the native QCs and establishment of dual anisotropies, arising from the values being different along the director as well in the two directions orthogonal to it. We also present data on voltage-driven switching between one of the anisotropic limits.

Keywords

• CsPbBr₃ perovskite quantum cuboids
• nanocomposites
• dual anisotropy
• switchable emission
• nematic liquid crystals
• linear assemblies