Defect Variants Based on the 2D Hybrid Organic–Inorganic Low-Dimensional Semiconductor (4-Fluoro-phenethylamine-H)₂PbBr₄ for Fabrication of Single-Layer Deep Blue LEDs

Abstract

The low-cost and self-assembled hybrid organic–inorganic semiconductors (HOIS) appear lately to be ideal for novel optoelectronic devices due to their inherent stable excitonic states, even at room temperature. 2D HOIS, superlattices of alternating layers of amines and of corner sharing lead halide octahedra, exhibit dielectrically confined bound excitonic states that are ideal for light emitting diodes (LEDs). HOIS-based deep blue LEDs are rarely reported, in which cases HOIS is usually deposited between electron and hole transport layers. Here, in the quest of suitable 2D HOIS for single layer LEDs (SLLEDs), we report on the synthesis and characterization of (4-fluoro-phenethylamine-H)2PbBr4 and its defect variations (DV), formed by nonstoichiometric synthesis. The DV thin films, deposited on conducting transparent anodes, allow for easy and simple fabrication of SLLEDs, using a Ga/In droplet cathode. The pristine iodine analogue readily provides green SLLEDs, while here only the DVs or pristine material’s mixtures with MoS2 nanosized platelets appear to function. It is suggested that the defects disrupt the long-range planar and insulating nature of the micrometric 2D HOIS crystalline platelets, thus, providing mechanisms for current flow, while the excitonic recombination half times are not affected by the defects. The organic 4-fluoro-phenethylamine enhances the EL functionality of the DVs compared to other amines because of the fluorine repulsion among the amine tails, leading to stable, weakly bound, organically decorated 2D inorganic sheets. It is expected that this work will provide incentive for utilizing HOIS DVs, being compatible with large scale synthesis.

Rigid Conjugated Diamine Templates for Stable Dion–Jacobson-Type Two-Dimensional Perovskites

“…Compared to PP-2I , FPP-2I ligand contains a fluorine atom on the ortho-position of one of the benzene rings. The fluorine substitution on the organic ligand also aids in the formation of high-quality 2D perovskite thin films. − Scanning electron microscopy (SEM) images (Figure S3) were also obtained and show that (PP)­PbI 4 , (FPP)­PbI 4 , and (FPT)­PbI 4 thin films have relatively similar morphologies as (PMA) 2 PbI 4 and are consistent with other 2D-HOIPs in the literature …”

ZnO Nanoparticles Photosensitization Using Ruthenium(II)‐polypyridyl Isomeric Complexes

“…The rapid growth of nanoscale semiconductor materials intended for appliances in photovoltaics has motivated the use of new alternatives for solar cell components . This is due to their novel optical properties, which have great potential for many other optoelectronic applications such as light‐emitting diodes (LEDs) . With a wide band gap of 3.37 eV and a low manufacture cost, ZnO semiconductors have been widely employed in sensors, optoelectronic devices, piezoelectric nanogenerators, catalysis and energy harvesting .…”

“…[4] This is due to their novel optical properties, which have great potential for many other optoelectronic applications such as light-emitting diodes (LEDs). [6] With a wide band gap of 3.37 eV and a low manufacture cost, ZnO semiconductors have been widely employed in sensors, [7] optoelectronic devices, [8] piezoelectric nanogenerators, catalysis and energy harvesting. [9,10] Compared to the well-developed titanium dioxide (TiO 2 ), nanostructured ZnO exhibits a similar band gap and higher charge mobility.…”