Info
Info
News Article

Researchers Tune Perovskite LED Wavelengths

News

German team uses waffle patterned wafer to tune size of semiconducting nanocrystals based on perovskite

Researchers at the Ludwig-Maximilians-Universitaet (LMU) in Munich have found a clever and economical way of tuning the colour of the light emitted by an LED by altering the size of their semiconductor crystals.

The exact wavelength of light emitted from LEDs is determined by the chemical composition of the semiconductor employed. In the case of some semiconducting materials, the colour can also be tuned by modifying the size of the crystals of which the light-emitting layer is composed. In crystals with dimensions on the order of a few nanometers, quantum mechanical effects begin to make themselves felt.

LMU researchers in collaboration with colleagues at the University of Linz (Austria) have now developed a method for the production of semiconducting nanocrystals of defined size based on the cheap mineral oxide perovskite. These crystals are extremely stable, which ensures that the LEDs exhibit high colour fidelity - an important criterion of quality. Moreover, the resulting semiconductors can be printed on suitable surfaces, and are thus suitable for the manufacture of LEDs for use in displays.

The crucial element in the new method is a thin wafer, only a few nanometers thick, which is patterned like a waffle. The depressions serve as tiny reaction vessels, whose shape and volume ultimately determine the final size of the nanocrystals. "Optimal measurements of the size of the crystals were obtained using a fine beam of high-energy X-radiation at the Deutsche Elektronen-Synchrotron (DESY) in Hamburg", says LMU researcher Bert Nickel, member of the Nanosystems Initiative Munich (NIM), a Cluster of Excellence.

Moreover, the wafers are produced by means of an economical electrochemical process, and can be fashioned directly into LEDs. "Our nanostructure oxide layers also prevent contact between the semiconductor crystals and deleterious environmental factors such as free oxygen and water, which would otherwise limit the working lifetime of the LEDs," as Martin Kaltenbrunner of the Johannes Kepler University in Linz explains. In the next step, we want to enhance the efficiency of these diodes further, and explore their potential for use in other applications, such as flexible displays.

'Confining metal-halide perovskites in nanoporous thin films' by Stepan Demchyshyn et al; Science Advances 04 Aug 2017:Vol. 3, no. 8



AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.

We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.

Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.

So make sure you sign up today and discover the latest cutting edge developments across the compound semiconductor and integrated photonics value chain.

REGISTER FOR FREE

VIEW SESSIONS

Info
×
Search the news archive

To close this popup you can press escape or click the close icon.
×
Logo
×
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
 
X
Info
X
Info
{taasPodcastNotification}
Live Event