Displays


Power-efficient, high-quality displays


The billboards of Times Square are a sight to behold. A hub of entertainment, tourism and culture, these dazzling displays use 161 megawatts of electricity annually and cost nearly $10 million to operate. Here Duncan Clark, of OLED innovator NextGen Nano, explores how this technology can be used to create bright, high contrast displays.


discovery of electroluminescence in organic materials, when the team applied alternating voltages to acridine orange die dissolved in and deposited on cellulose. Today, Bernanose is thought of as the father of OLED technology and the market is worth an estimated $18 billion.


I


CrEATiNG HiGH CONTrAST DiSpLAyS OLEDs consist of an organic semiconductor material sandwiched between an anode and cathode. When an electrical current is applied to the semiconductor, a diffuse-area luminance is achieved. While traditional light-emitting diodes (LEDs) produce a small-point light source, OLED emissions are comparatively softer, producing less glare. One of the biggest selling points


for OLEDs, is their ability to render a state of true black, which means they can and produce higher contrast displays. In a practical example, liquid-crystal display (LCD) televisions require LED backlighting to produce light, which is then filtered by the LCD. As a result, these devices cannot achieve true black and power will be consumed even when rendering a black display. OLEDs do not have this issue.


Inactive OLEDs do not emit light or consume power, allowing for greater contrast ratios and better overall viewing experiences. Removing the need for a backlight also makes OLED devices lighter in weight and


60


n the 1950s, André Bernanose and co-workers at the Nancy- Université, France, made the first


gives them wider viewing angles. It is because of these properties that companies like Sony and LG have used OLEDs to produce sleeker, thinner flatscreen displays. As with any light source, increasing


the electrical current through the OLED semiconductor will result in brighter displays. However, by doing this, the lifetime of the device is shortened as the increased current causes the OLED to degrade at a faster rate. This is where NextGen Nano’s research shines best. Published in Nature


Communications in 2019, NextGen Nano’s New Fusion division found that certain organic semiconductors achieved fluorescence at lower energy values than for OLEDs used today. The study found that the OLEDs produced 1,000 candela per square metre at 3.4 volts — approximately 50 per cent of the voltage required by current OLEDs. High driving voltages traditionally


excite the organic semiconductor too much, causing it to degrade quickly. Therefore, this research on OLEDs not only underlines the potential of improved power efficiency, but also highlights how they can operate for longer without deteriorating. From Bernanose’s discovery in the


1950s, to the use of OLEDs today in high contrast displays, OLED technology continues to excite — one day soon, we might even see them lighting up the displays at Times Square.


NextGen Nano nextgen-nano.co.uk


March 2021 Instrumentation Monthly


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74