EP05.07.16 : Structural Modulating Quasi-2D Perovskite for Efficient Light-Emitting Diodes

5:00 PM–7:00 PM Apr 5, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Hyeon-Dong Lee1 Hobeom Kim1 Wonhee Cha2 Chang-Lyoul Lee3 Dongho Kim2 Hoichang Yang4 Tae-Woo Lee1

1, Seoul National University, Seoul, , Korea (the Republic of)
2, Yonsei University, Seoul, , Korea (the Republic of)
3, Advanced Photonics Research Institute, Gwangju, , Korea (the Republic of)
4, Inha University, Seoul, , Korea (the Republic of)

Metal-halide perovskites (hereafter, perovskite) are promising materials for the application as a light emitter of light-emitting diodes (LED) based on their narrow emission spectrum and the tunable bandgap. However, the perovskite with 3D lattice structure has been considered inefficient to confine excitons leading to dissociation, which is unfavorable for the development of efficient perovskite LEDs. While the 2D or quasi-2D perovskite where organic ammonium (OA) with long chain (e.g. phenethylammonium) is incorporated can effectively confine excitons, the insulating OA in a certain preferred orientation limits efficient charge transfer and transport in the perovskite film. In this work, we induced structural modulation of quasi-2D perovskite, (PEA)2(MA)m-1PbmBr3m+1 by applying nanocrystal pinning (NCP) process. The structurally modulated quasi-2D perovskite had random orientation that was confirmed by Grazing Incidence X-ray Diffraction (GIXRD) analysis. Because the modulated quasi-2D perovskite can have connected inorganic layers, charge transfer and transport can easily occur leading to efficient radiative recombination maintaining exciton confinement effect. We developed perovskite LEDs with the modulated quasi-2D perovskite emitter by controlling the ratio between phenethylammonium bromide (PEABr) and methylammonium bromide (MABr). The device with the modulated quasi-2D perovskite, (PEA)2(MA)2Pb3Br10 had the maximum current efficiency of 20.18 cd/A and maximum external quantum efficiency of 4.98 %