Origin of Edge Emission in Two-Dimensional Ruddlesden-Popper Hybrid Perovskites

Two-dimensional (2D) Ruddlesden-Popper (RP) perovskites, with high quantum efficiency, good photostability and chemical stability, are promising for optoelectronic devices. Blancon et al. reported firstly the lower photoenergy edge emission at those (BA)₂(MA)_n-1Pb_nI_3n+1 2D RP perovskites when n≥3 in 2017[1]. Then, significant attention was attracted to explore the mechanism of edge emission. A theoretical work following them was published to assert that this edge emitting originates from interface strain[2]. After that, another work declared that the edge emission is induced by water molecules[3]. The discussion of Zhao et al. indicated that the loss of part BA at edges should be responsible for the edge emission[4]. While, a reliable and consistent explanation is still missing till now. In this work, we observe the edge emission in 2D exfoliated perovskites and clarify the mechanism of edge emission. This work reveals the nature of the edge emission and pave a way for developing the new optoelectronic devices based on the 2D RP hybrid perovskites.
[1]Blancon J. C., et al., Science, 2017, 355, 1288-1292.
[2]Kepenekian, M., et al., Nano Lett, 2018, 18, 5603-5609.
[3]Shi, E., et al., ACS Nano, 2019, 13, 1635-1644.
[4]Zhao, C., et al., J Phys Chem Lett, 2019, 10, 3950-3954.