The new molecule designed by the researchers was based on encapsulating blue emitters with insulating alkylene tapes (Northumbria University)
Imagine that you have a beautiful painting made up of different colored dots, but among them the blue dots are a bit of a problem, as they tend to flicker or fade faster than others, which can damage the painting over time.
This is exactly what happens in OLED screens. The dots on the panel are the pixels on the screen that emit light to form the general image, and there is a problem of power loss in the sub-pixels that emit blue light. However, a research team from four British universities (Northumbria, Cambridge, Imperial and Loughborough) announced that it had found a solution, which could lead to television screens that last longer and have higher image quality.
How do OLED screens work?
OLED screens, or what is known as “organic light-emitting diode,” are a type of display technology used in various electronic devices such as smartphones, televisions, computer screens, and wearable devices.
Unlike traditional LCD screens, which require a separate backlight to illuminate the pixels, these screens contain organic compounds that emit light when an electrical current is applied.
To understand what the researchers did in the new study published in the journal Nature Materials, you must know how these screens work, which consist of:
Multiple organic layers sandwiched between two electrodes, usually made of glass or plastic. These layers include an emissive layer, a conductive layer, and sometimes additional layers to improve performance.
When an electric current passes through these organic layers, it stimulates the organic molecules in the emitting layer, resulting in the emission of light. The color of the emitted light depends on the specific organic material used in the emitting layer.
Each individual pixel on the screen is made up of three sub-pixels: red, green and blue. By varying the intensity of the light emitted by each sub-pixel, OLED displays can create a wide range of colors and achieve high color accuracy and vividness.
The new molecule designed by researchers emits pure blue light that acts as a shield that prevents energy loss in screens (Northumbria University)
Although these screens are distinguished by their vivid picture quality, they also have disadvantages such as high cost and relatively short lifespan, and one of the main reasons for this is that the commonly used organic materials that emit blue light when electricity passes through them, sometimes waste energy, which It causes damage to the screen structure and destroys viewing quality.
Extra armor to heal negatives
Organic substances commonly used as blue emitters in OLED displays are aromatic hydrocarbons known as fluorenes, carbazoles, anthracene derivatives, heterocyclic compounds known as phenanthroline, iridium, and... Dibenzothiophene.
While these organic materials provide advantages as blue emitters in screens, it is their waste of energy - causing damage to screens and ruining viewing quality - that prompted researchers to design a new molecule with additional shielding.
Just as you might try to reinforce a weak spot in a wall with stronger materials, the additional shielding in the new molecule blocks pathways where energy could be wasted, making the blue pixels more stable and efficient, and less likely to degrade over time.
In addition, this new molecule emits extremely pure blue light, which enhances the overall image quality on OLED displays. This improvement allows for brighter and longer-lasting blue pixels, which is crucial for maintaining high-quality images. Quality and cost reduction in screen production.
The new “armored blue” will increase the life of devices and screens, helping to reduce the volume of electronic waste (Northumbria University)
How was the new molecule designed?
The new molecule's design is based on encapsulating blue emitters with insulating "alkylene" bands. This molecular design aims to eliminate energy loss, a process known as "Dexter energy transfer," which is named after Richard Dexter, the American scientist who described this energy loss. The first time in the 1950s.
To understand this process, imagine a group of friends passing the ball to each other. In this case, the ball represents energy. A “Dexter transfer” occurs when one friend passes the ball (energy) to another friend, but instead of catching it well, the second friend drops it or does something wrong. Dealing with it, that means losing some energy.
So, researchers want to stop this inefficient passage of energy to make OLED displays work better, and the way to achieve this is to design a new molecule to prevent wasteful energy transfer from occurring.
“Thanks to this new molecule, we have created a path to developing more efficient OLED displays, in addition to helping reduce the energy consumption of our devices,” said Mark Etherington, assistant professor of molecular photophysics and lead researcher on the study, in a press release issued by Northumbria University. He adds, "While we are all working to achieve net-zero emissions goals, this achievement can bring great benefit to both manufacturers and consumers."
Reducing the volume of electronic waste
Professor of Electronics Engineering at Zagazig University (northeast of Cairo), Ibrahim Gad, captures another environmental benefit of this achievement. He said in a telephone interview with Al Jazeera Net: “It will increase the life of the devices in a way that helps reduce the volume of electronic waste, which is the problem that reports indicate.” Internationally, it is increasing year after year.
According to the United Nations Global E-Waste Monitor 2020, the volume of waste reached 53.6 million metric tons (a metric ton equals one thousand kilograms) worldwide in 2019, and is expected to reach 74 million tons by 2030.
Burning this waste for disposal leads to the release of harmful pollutants and greenhouse gases into the atmosphere, which may give an important environmental advantage to this achievement, which extends the life of devices as part of global efforts to reduce emissions, as Gad confirms.
But he came back and said: “This additional advantage will be worthless if the new molecule developed by the researchers does not give a better and purer image.”
The new “Armored Blue” will increase the life of devices, helping to reduce electronic waste (Getty)
While the laboratory experiments conducted by the researchers indicate that they succeeded in this, Gad confirms that in order for the achievement to move from the laboratory to application, additional studies need to be conducted, such as:
Characterization studies
: This is to further analyze the molecular structure, optical properties, and electronic behavior of the new molecule through techniques such as spectroscopy, microscopy, and computational modeling, as this can provide deeper insights into how the molecule works inside OLED screens, and its interaction with other components.
Long-term stability studies
: These include evaluating the degradation mechanisms of the molecule and life expectancy, and this is crucial to evaluating the commercial viability and durability of the new molecule in practical applications.
Scale-up and manufacturing studies
: They aim to explore the scalability, cost-effectiveness, and manufacturability of producing the new molecule on a commercial scale.
Environmental and health impact studies
: They aim to evaluate the environmental and health impacts associated with the installation, use and disposal of the new molecule, including environmental toxicity assessments and its survival rate in the environment after the end of the device’s life.
Source: Al Jazeera + websites