Organic emitters for solid state lighting

Abstract

White organic light emitting diodes (WOLEDs) have gained considerable attention of academic and industrial research communities as promising alternative to incandescent lamps, fluorescent tubes and inorganic LEDs for low energy consumption lighting applications. WOLEDs are expected to become one of the next generation lighting sources because of their high color tunability and color quality, which can be easily achieved by proper chemical design of organic electroluminescent materials. Contrary to their inorganic counterparts, WOLEDs also bear the distinctive feature of being available as flexible and large area devices. Over the last decades, a lot of efforts have been spent on defining suitable strategies to highly efficient WOLEDs based on the use of properly tailored organic emitters. Here we survey the main chemical approaches to white electroluminescence from organic light emitting materials, highlighting strong and weak points of each strategy. Current research on new hybrid white light emitting devices based on the combination of inorganic LEDs and organic down color converters is also reviewed by some representative examples.

Optoelectronic Organic–Inorganic Semiconductor Heterojunctions

“…Advantages of white organic LEDs (WOLEDs/OLEDs) include low-cost fabrication, ease of processability, fabrication of large area flexible sheets and tuning of their emission properties through modification of the chemical structure [8,33,34]. In order to generate white light, emissive materials of varying colour need to be combined, which can be achieved by several approaches [9]. One approach uses several individual emitters arranged in a multilayer structure, or by blending individual emitters into a single layer or by doping a host material with emissive materials at varying concentrations [35][36][37].…”

“…Their thin film deposition allows the fabrication of large area and flexible devices. The absorption and emission properties of these organic materials can be directly influenced and tuned by modifying and adjusting their chemical structure [9].…”

Luminescent cis-Iridium(III) Complex Based on a Bis(6,7-dimethoxy-3,4-dihydroisoquinoline) Platform Featuring an Unusual cis Orientation of the C∧N Ligands: From a Theoretical Approach to a Deep Red LEEC Device

“…Since the first commercialized OLED device (1987), the research on OLEDs rapidly has passed through the design of more and more efficient devices, by exploiting first the emitting properties of fluorescent polymers and/or small molecules and then the more performing phosphorescent transition-metal complexes. 1−3…”

Synthesis and Characterization of Highly Efficient Solution‐Processable Green Ir(III) Complexes with High Current Efficiency and Very Low Efficiency Roll‐Off

“…Heteroleptic Ir(III) complexes [(C^N) 2 Ir(LX)] bearing two 2‐arylpyridinate(C^N) and one ancillary (LX) ligands are among the most promising phosphorescent emitters for optoelectronics and lighting applications . With the strong spin–orbit coupling of heavy metal phosphors, they have high quantum efficiencies and easier synthetic accessibility than their homoleptic Ir(III) complex [Ir(C^N) 3 ] counterparts, along with an emission wavelength that is conveniently tunable by systematic design and functionalization of the organic ligands .…”