Organic light‐emitting diode (OLED) technology: materials, devices and display technologies

Abstract

Since the breakthrough by Kodak in 1987, organic light-emitting diodes (OLEDs) have been seen as one of the most promising technologies for future displays. A number of materials have been developed and improved in order to fulfil the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence). When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry. The circuitry for driving the pixels can be adapted to the OLED, sometimes at the expense of the simplicity of the display, but bearing in mind that the fabrication process must remain industrially viable.

Direct observation of epitaxial organic film growth: temperature-dependent growth mechanisms and metastability

“…[1][2][3] It is established that in general the optical and electronic properties of such films may strongly depend on their structural properties. 4 These, in turn, are not only influenced by the molecular shape and the intermolecular interaction forces but also by the preparation conditions including parameters like type of substrate, chemical and geometric structure of the substrate surface, geometry and functional groups of the molecules, deposition rate and temperature.…”

“…Thus, for the optimization of function and efficiency of an organic thin film a deep understanding of the mechanisms of film growth and interface formation is required. [1][2][3][4] Compared to the very well understood atomic growth of metals or inorganic semiconductors, the growth of organic molecular films tends to be much more complex due to the larger size of the molecules, different bonding mechanisms, role of functional groups, anisotropic molecular structure, molecular orientation, etc.…”

Vapor phase oxidative synthesis of conjugated polymers and applications

“…OLEDs have received increasing demand in the display market (such as in screens for televisions, computers, and mobile devices) because of their many advantages, such as bright light output and low energy consumption. 102,105 Similar to the work to replace inorganic electrode materials in OPVs by vapor-deposited PEDOT, OLED devices using VPP PEDOT anodes have been successfully demonstrated by Levermore et al 28,37 They optimized the film thickness (40 nm), conductivity ( 1180 S cm À1 ), and work function (4.6 eV) of VPP PEDOT layers for OLED application. ITO-free OLEDs were fabricated on glass and plastic substrates with the following structure: substrate/VPP PEDOT/PEDOT:PSS/emissive layer/ cathode.…”

An Organic Field-effect Transistor with an Extended-gate Electrode Capable of Detecting Human Immunoglobulin A

“…To date, academic and industrial research on organic electronic devices such as light-emitting diodes, 1 solar cells 2 and transistors 3 has flourished in the field of electronic engineering. Especially, attempts have been made to use organic field-effect transistors (OFETs) as printed flexible integrated-electronic-circuits, screen displays, 4 and radio frequency identification (RFID) tags.…”