Advances in Organic Light-Emitting Diodes (OLEDs)
Introduction
Organic Light-Emitting Diodes (OLEDs) are a type of LED in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, portable systems such as smartphones, handheld game consoles and PDAs. A major area of research is the development of white OLED devices for use in solid-state lighting applications.
History
The development of OLED technology dates back to the 1950s and 1960s, but the first practical OLED device was not developed until 1987 by Ching Tang and Steven Van Slyke at Kodak. The duo was awarded the 2011 Nishizawa medal for their pioneering contributions to the development and commercialization of OLED technology.
Structure
An OLED display works without a backlight because it emits visible light. Thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions such as a dark room, an OLED screen can achieve a higher contrast ratio than an LCD, regardless of whether the LCD uses cold cathode fluorescent lamps or an LED backlight.
Advantages and Disadvantages
OLED displays are lighter, more flexible, and can be made to larger sizes than their LED or LCD counterparts. They also have a faster refresh rate, better color accuracy, and can produce a more realistic black color. However, they are more expensive to produce, have a shorter lifespan, and can suffer from color balance issues over time.
Advances in OLED Technology
Significant advances have been made in OLED technology since its inception. These include the development of flexible and transparent OLED displays, the improvement of OLED lifespan, and the reduction of manufacturing costs.
Flexible OLEDs
Flexible OLED displays have been developed by several companies, including Samsung and LG, and are used in products such as the Samsung Galaxy Round and the LG G Flex. These displays are made by placing a thin layer of flexible organic materials between two flexible electrodes.
Transparent OLEDs
Transparent OLEDs use transparent or semi-transparent contacts on both sides of the device to create displays that can be made to be transparent or partially transparent. This allows for innovative applications such as heads-up displays and smart windows.
Lifespan Improvements
The lifespan of an OLED display has been a major concern in the past, but recent advances have increased the lifespan significantly. This has been achieved through the development of new organic materials and the use of encapsulation techniques to protect the organic materials from moisture and oxygen.
Cost Reduction
The cost of manufacturing OLED displays has been a major barrier to their widespread adoption. However, advances in manufacturing techniques, such as the use of inkjet printing, have reduced the cost significantly.
Future of OLED Technology
The future of OLED technology looks promising, with ongoing research and development aimed at improving the efficiency, lifespan, and cost-effectiveness of OLED displays. There is also significant interest in the development of OLED lighting, which could potentially offer more efficient and environmentally friendly alternatives to traditional light sources.