Marked Efficiency Improvement of FAPb0.7Sn0.3Br3 Perovskite Light-Emitting Diodes by Optimization of the Light-Emitting Layer and Hole-Transport Layer

Abstract

Highly luminescent FAPb0.7Sn0.3Br3 nanocrystals with an average photoluminescence (PL) quantum yield of 92% were synthesized by the ligand-assisted reprecipitation method. The 41-nm-thick perovskite film with a smooth surface and strong PL intensity was proven to be a suitable luminescent layer for perovskite light-emitting diodes (PeLEDs). Electrical tests indicate that the double hole-transport layers (HTLs) played an important role in improving the electrical-to-optical conversion efficiency of PeLEDs due to their cascade-like level alignment. The PeLED based on poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,40-(N-(p-butylphenyl))-diphenylamine)] (TFB)/poly(9-vinylcarbazole) (PVK) double HTLs produced a high external quantum efficiency (EQE) of 9%, which was improved by approximately 10.9 and 5.14 times when compared with single HTL PVK or the TFB device, respectively. The enhancement of the hole transmission capacity by TFB/PVK double HTLs was confirmed by the hole-only device and was responsible for the dramatic EQE improvement.

Unraveling the Luminescence Quenching Mechanism in Strong and Weak Quantum-Confined CsPbBr3 Triggered by Triarylamine-Based Hole Transport Layers

“…Typical CsPbBr 3 NPLs consist of long-chain surface passivating ligands such as oleic acid and oleyl amines, A- and B-site ions, and halide ions. Any of these can form bonds with the transport layers and create nonradiative channels at the interface. ,, Often, in PeLEDs, poly­(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS), poly­[(9,9-dioctylfluorenyl-2,7diyl)-co-(4,4′-(N-(4-sec-butylphenyl) diphenylamine)] (TFB), poly­( N -vinylcarbazole) (PVK), poly­( N , N ′-bis-4-butylphenyl- N , N ′-bisphenyl)­benzidine (PolyTPD), 1,1-Bis­[(di-4-tolylamino)­phenyl]­cyclohexane (TAPC), and poly­(bis­(4-phenyl)­(2,4,6-trimethylphenyl)­amine) (PTAA) are employed as hole transport layers (HTLs). ,,− Notably, many of these HTLs, such as TFB, PolyTPD, PTAA, and TAPC, possess triarylamine functionality and are known for interfacial luminescence quenching. ,,− …”

“… 6 , 9 , 35 − 38 Notably, many of these HTLs, such as TFB, PolyTPD, PTAA, and TAPC, possess triarylamine functionality and are known for interfacial luminescence quenching. 6 , 34 , 39 − 41 …”

Antimony-Doped Tin Oxide Hole Injection Interlayer Improving the Efficiency of Perovskite Nanocrystal Light Emitting Diodes

“…To reduce this energetic barrier Xiao et al introduced a ultrathin thermally evaporated MoO 3 between PEDOT:PSS and PVK to form an interfacial dipole and improve hole injection in a FAPb 0.7 Sn 0.3 Br 3 -based device resulting in enhanced higher luminance and current efficiency . Hu et al implemented a double interlayer concept consisting of TFB/PVK that provided enhanced current efficiency and external quantum efficiency for FAPb 0.7 Sn 0.3 Br 3 -based PNC LEDs compared to single TFB or PVK interlayer based devices . In another work, Li et al introduced a thermally evaporated ultrathin (2 nm) LiF between the PEDOT:PSS and the MAPbBr 3 emissive layer.…”