Boosting the Efficiency of NiO_x-Based Perovskite Light-Emitting Diodes by Interface Engineering

Abstract

Nickel oxide (NiO x ) is a promising hole-transporting material for perovskite light-emitting diodes (PeLEDs) because of its low cost, excellent stability, and simple fabrication process. However, the electroluminescence efficiencies of NiO x -based PeLEDs are greatly limited by inefficient hole injection and exciton quenching at the NiO x –perovskite interfaces. Here, a novel interfacial engineering method with sodium dodecyl sulfate-oxygen plasma (SDS-OP) is demonstrated to simultaneously overcome the aforementioned issues. Experimental results reveal that a short OP treatment on the top of the SDS-coated NiO x significantly deepens the NiO x work function (from 4.23 to 4.85 eV) because of the formation of a large surface dipole, allowing for efficient hole injection. Moreover, the SDS-OP layer passivates the electronic surface trap states of perovskite films and suppresses the exciton quenching by NiO x . These improvements inhibit the nonradiative decays at the NiO x –perovskite interface. As a result, the external quantum efficiency of CsPbBr3 LEDs is increased from 0.052 to 2.5%; that of FAPbBr3 nanocrystals LEDs is increased from 5.6 to 7.6%.

Printable and Homogeneous NiOx Hole Transport Layers Prepared by a Polymer‐Network Gel Method for Large‐Area and Flexible Perovskite Solar Cells

“…In Figure 2e, the Ni p3/2 peaks of NiO x NPs are mainly located at binding energies of 853.5 and 855.4 eV for Ni 2+ and Ni 3+ , which evidence that the composition of NiO x film is nonstoichiometric. [41][42][43] The ratios of Ni 2+ /Ni 3+ calculated from the integral area in the Ni 2p spectrum change from 4:5 to 5:4, the improvement of the crystal quality of NiO x effectively inhibits the generation of crystal defects and prevents Ni 2+ from being oxidized to Ni 3+ by the external environment. It is important to mention that these Ni 3+ state compounds can chemically react with the perovskite at the interface, thereby inducing the degradation of the perovskite and reducing the stability of PSCs.…”

Defect Behaviors in Perovskite Light-Emitting Diodes

“…238 To improve the hole injection of NiO x , Wang et al proposed an interface engineering method, based on sodium dodecyl sulfate−oxygen plasma (SDS-OP). 239 The short oxygen plasma treatment was found to significantly deepen the work function of NiO x by forming large surface dipoles, thereby allowing effective hole injection. Similarly, ZnO is also often used as a carrier transport layer.…”

Revealing the Substitution of Zn2+ on Nano-Structural, Magneto-Electrical, Antibacterial and Antifungal Attributes of Nickel Oxide Nanoparticles via Sol-Gel Strategy

“…These form of interactions have a significant impact on the electromagnetic characteristics of the nanomaterial and in turn, the spin-based multifunctional devices have assorted applications in the scope of spin-polarized light emitting diodes (LEDs), sensors, spintronics, photovoltaic, magneto-optoelectronics, high-density information storage, quantum computing, field-effect transistors, etc. credited to its faster data processing speed, non-volatility and greater integration densities, etc [22][23][24]. ZnO being the n-type semiconductor with bandgap energy of ~3.32 eV and exciton binding energy 60 MeV, is reported as a biocompatible compound viz., extreme resistant towards microbes, heat resistant, reduced toxicity material with a wide range of applications including transparent electronics, piezoelectric, chemical and biological sensors, as an antimicrobial agent and in catalytic processes.…”