Near-Infrared Light Emitting Diodes based on an Oxygen Moiety Containing 2D Ruddlesden-Popper Perovskites

Abstract

Near-infrared perovskite light-emitting diodes (NIR-PLEDs) face a challenge in regards to achieving high external quantum efficiency (EQE) and color purity in displays. However, low charge mobility in addition to Auger or excitonic quenching hinders the realization of high-performance NIR-PLEDs. We report in this study efficient and color stable NIR-PLEDs using the 2D Ruddlesden-Popper (RP) perovskite (TFF)2(CH3NH3)n-1PbnI3n+1 (TFF: C4OH7CH2NH3, MA: CH3NH3, and n = 2, 3, 4). The (TFF)2(MA)Pb2I7 crystallizes in a centrosymmetric monoclinic space group (C2/c), which the individual [Pb2I7]3- slabs are separated by the (TFF2)2+ bilayer with an empty space, and it maximizes the quantum confinement in the 2D layered structure. The (TFF)2(MA)Pb2I7 perovskite exhibits dual band emissions peaks at 590 nm and 750 nm. The high energy emission peak (590 nm) in (TFF)2(MA)Pb2I7 redshifted to 630 nm in the (TFF)2(MA)2Pb3I10 compound. The (TFF)2(MA)Pb2I7 perovskite LED shows 4.44% EQE at current density of 6.97 mA cm-2 and 14.42 cd m-2 maximum brightness at applied bias voltage of 4 V. This study presents that it is possible to control the emission wavelength by using the organic spacer as well as the dimensionality of perovskite.