Designed Polymer Ligands for Perovskite Quantum Dots and Their Block Copolymer Nanocomposites

Perovskite quantum dots (QDs) have efficient optical absorption and emission in the visible range, and show a strong quantum confinement effect and high external quantum efficiency. They have been at the forefront of next-generation photovoltaics and optoelectronics applications. However, two major challenges associated with perovskites and their nanomaterials are poor stability (such as against moisture and polar solvents), as well as the lack of efficient nanopatterning methods. In this work, a promising approach is provided to address both of those major challenges by molecular engineering and integration of QDs with block copolymers (BCP). The BCP thermoplastic elastomers not only substantially improve the stability of perovskite QDs by encapsulating them in a highly stable and soft matrix, but also enable molecular-level control of the alignment and assembly of perovskite QDs in the microphase-separated BCP matrix. It is demonstrated that designing and synthesis of compatible polymer ligands for perovskite QDs is key to enabling their selective and strong interaction with the BCP matrix. The structure and molecular weight of the BCP also play an important role in the interfacial structure and optical properties of the QDs-BCP nanocomposites. Such soft and flexible optical nanocomposites have potential applications in flexible optoelectronics, optical storage, and displays. By designing functional polymer ligands for perovskite quantum dots and integrating them with a flexible block copolymer matrix, soft and stretchable optical materials with significantly enhanced stability and mechanical properties are achieved, which have potential applications in flexible displays, LEDs, and sensors.image