Lakshminarayana Polavarapu1 2 Yu Tong1 2 Bernhard Bohn1 2 Alexander Urban1 2 Jochen Feldmann1 2

1, Ludwig Maximillians University, Munich, Munich, , Germany
2, Nanosystems Initiative Munich (NIM), Munich, , Germany

Perovskite NCs are gaining increasing attention in many fields ranging from chemistry to physics and engineering owing to their extremely interesting properties such as high photoluminescence quantum yields, tunable optical bandgap, enhanced stability, large diffusion lengths and shape controllability [1-4]. In spite of the rapid progress in the shape-controlled synthesis of perovskite NCs, very few attempts have been made toward the understanding of their growth mechanisms and morphology-dependent optical properties. These studies require interdisciplinary research collaborations.

In this talk, we will present a facile synthesis of single-crystalline CsPbBr3 perovskite nanowires (NWs) directly by ultrasonication of their precursor powders [5]. The optical and morphological evolution revealed that initially CsPbBr3 nanocubes are formed, which transformed into NWs through an oriented-attachment mechanism. The optical bandgap of the NWs can be controlled over the entire visible range by varying the halide (Cl, Br, and I) composition through a subsequent halide ion exchange step. Furthermore, we have demonstrated that these NWs can self-assemble in a quasi-oriented fashion by the Langmuir–Blodgett technique. This work not only provides a facile method to synthesize highly monodisperse perovskite NWs, but also expands our current understanding of the growth mechanism and optical properties, and open new avenues for the fabrication of highly ordered architectures using perovskite NC building blocks for future optical and optoelectronic devices.

(1) Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.; Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A.; Kovalenko, M. V. Nano Lett. 2015, 15, 3692.
(2) Tong, Y.; Bladt, E.; Aygüler, M. F.; Manzi, A.; Milowska, K. Z.; Hintermayr, V. A.; Docampo, P.; Bals, S.; Urban, A. S.; Polavarapu, L.; Feldmann, J. Angew. Chem. Int. Ed. 2016, 55, 13887.
(3) Hintermayr, V. A.; Richter, A. F.; Ehrat, F.; Döblinger, M.; Vanderlinden, W.; Sichert, J. A.; Tong, Y.; Polavarapu, L.; Feldmann, J.; Urban, A. S. Adv. Mater. 2016, 28, 9478.
(4) Polavarapu, L.; Nickel, B.; Feldmann, J.; Urban, A. S. Adv. Energy Mater. 2017, 7, 1700267
(5) Tong, Y.; Bohn, B. J.; Bladt, E.; Wang, K.; Müller-Buschbaum, P.; Bals, S.; Urban, A. S.; Polavarapu, L.; Feldmann, J. Angewandte Chemie International Edition 2017, 56, 13887.