Technical / Research

UK researchers develop promising new hyperfluorescence blue OLED materials

Researchers from the UK's Northumbria, Cambridge, Imperial and Loughborough universities developed a new Hyperfluorescence OLED emitter system based on a new molecular design, which is highly efficient and simple to produce.

The researchers explain, that in Hyperfluorescence  systems, the elimination of the Dexter transfer to terminal emitter triplet states is the key towards OLED efficiency and stability. Current devices rely on high-gap matrices to prevent Dexter transfer, which unfortunately leads to overly complex devices from a fabrication standpoint. The researchers developed a novel molecular design in which ultranarrowband blue emitters are covalently encapsulated by insulating alkylene straps. 

Read the full story Posted: Mar 17,2024

OLED-based data communication of up to 3GB/sec enabled by new device structure

Researchers from CEA-Leti and the Université Sorbonne Paris-Nord (USPN) developed a new OLED structure that enabled them to achieve two new world records for OLED-based data communication, a bandwidth of 450 Mhz and a transmission throughput of almost 3GB/sec. This more than doubles the previous OLED record. The researchers say that this proves that OLEDs can play a role in future fast photonic-based data communication, which was limited to in-organic microLED devices up until now.

The researchers developed a new OLED structure, in order to find the best compromise between speed, light performance and device size. The researchers used evaporation to deposit 7 layers of various organic materials while precisely controlling how they fit together and stack. The whole device is only 40 um in size.

Read the full story Posted: Mar 11,2024

Researchers develop a new multi-functional encapsulation that can be used to produce fiber-based wearable OLEDs

Researchers from Korea's Gachon University, Seoul University and Chungbuk University developed a multi-functional encapsulation technology that can be used to develop fiber-based wearable OLED devices, deposited on textiles.

The new OLED device is produced on a light extraction substrate, that is super-hydrophobic - developed by coating a water-repellent layer on a rough surface obtained through ion beam treatment, ensuring excellent uniformity and easy power control. The new encapsulation offers high performance (10-6 g/m-2/day) and also achieves a UV transmission rate of less than 3%.

Read the full story Posted: Feb 23,2024

Samsung researchers collaborate with the UK's NPL to better understand blue OLED degradation mechanisms

Researchers from the UK's National Physical Laboratory (NPL), together with the Samsung Advanced Institute of Technology (SAIT), released a new study to better understand the degradation of blue OLED devices. 

Close-up of the OrbiSIMS instrument’s vacuum chamber showing the nozzles of the ion beams and electrode that extract ionised molecules for analysis (Picture credit: NPL)

The OLED degradation mechanisms that limit the lifetime of blue OLED emitters, whether physical, chemical or something else, are still not yet fully understood. Understanding the degradation mechanism of blue OLEDs is essential to improve their performance and stability. The NPL / SAIT team used OrbiSIMS, an innovative mass spectrometry imaging technique invented at NPL in 2017, to study OLED degradation. 

Read the full story Posted: Feb 15,2024

Researchers from Durham University use long-forgotten OLED emitter molecules to enable highly efficient hyperfluorescence OLED devices

Researchers Durham University, led by Professor Andrew Monkman, discover new OLED emitters that offer high performance in a hyperfluorescence emission system. The main new material, a molecule called ACRSA, was found to triple the efficiency of hyperfluorescence OLED devices.

These OLED emitters aren't actually new - they were studied years ago, but were found to be poor emitters. That was true when used as OLED emitters, but when used in a hyperfluorescence system (which combines both fluorescent and TADF emitters), these were surprisingly efficient. The ACRSA emits a green emission, but deep blue light emission can be achieved by transferring ACRSA's energy to a blue terminal emitter. This approach reduces exciton energy compared to direct blue emission in devices, allowing more stable, longer-lasting blue OLEDs.

Read the full story Posted: Feb 13,2024

Researchers develop a perovskite-based 3D printing ink that could power next generation OLED devices

Researchers at Lawrence Berkeley National Laboratory (Berkeley Lab), led by Prof. Peidong Yang, developed a new 3D printing ink based on perovskite materials, that exhibits unity photoluminescence quantum yield (PLQY). Interestingly, as it is a 3D printable ink, it is possible to create luminescent objects from it, as seen in the image below:

The researchers brand the new ink as 'supramolecular ink', and say it is produced without any rare metals. It is a combination of several powders containing hafnium (Hf) and zirconium (Zr), and is made at room temperatures. In a process called supramolecular assembly, tiny molecular building block structures are self-assembled within the ink. These supramolecular structures enable the material to achieve stable and high-purity synthesis at low temperatures.

Read the full story Posted: Feb 08,2024

Toray Research Center shows how OLED inspection and analysis enable the production of higher performance OLED panels

Toray Research Center (TRC) has launched a new open online webinar focused on OLED inspection and analysis technologies. TRC, who supplies technical analysis and support for R&D and manufacturing, invites you to attend the online lectures at no cost, to get a deeper understanding on OLED inspection and analysis, and how to achieve higher performance displays. The webinar recordings are accessible until February 15.

Toray Research Center TRC banner

The webinar include four presentations:

  • Identification of Trace Impurities Using High-Resolution Mass Spectrometry (Toward High-Quality OLED Panels)
  • Analysis of Small Molecule OLED Layers in Solution Process and Vacuum Deposition Process
  • Moisture Diffusion Evaluation in Encapsulant
  • Analysis of QD sheet (Quantum Dot Enhancement Film)

The first presentation, titled Identification of Trace Impurities Using High-Resolution Mass Spectrometry (Toward High-Quality OLED Panels), details examples of possible degradation in OLED devices that lead to performance reduction. In this presentation, TRC discusses the role of analysis, the advantages of high mass resolution, different evaluation techniques and how it can help developers increase the performance of OLED displays.

Read the full story Posted: Feb 06,2024

Single-layer TADF OLEDs outperform the best multi-layer device in both efficiency and lifetime

In 2023, we reported on research conducted at Germany's Max Planck Institute, led by Prof. Paul W.M. Blom, that looks into single-layer OLED devices. In such devices, a single TADF OLED emitter layer is sandwiched between two electrode - a much simpler design compared to commercial OLED devices that use multilayer stacks, sometimes with 10 or more layers. The researchers the the MPI say that in fact it is possible to develop highly efficient OLEDs with just the TADF emitter - and have demonstrated 100% IQE single-layer devices, with an EQE of 27.7%

Prof. Blom's group continues to improve its single-layer TADF OLED device, and have now reported that by employing a recently developed trap-free large band gap material as a host for the DMAC-BP OLED emitter, a nearly balanced charge transport is achieved. The device achieves a record power efficiency for DMAC-BP TADF OLEDs of 82 lm/W - surpassing  the best reported multilayer power efficiencies of 52.9–59 lm/W. This is due to the lower operating voltage. The single-layer device reaches an external quantum efficiency (EQE) of 19.6%, which is only slightly lower than the reported EQEs of 18.9–21% for multilayer devices. In addition to the high power efficiency, the operational stability is greatly improved compared to multilayer devices and the use of conventional host materials in combination with DMAC-BP as an emitter.

Read the full story Posted: Feb 02,2024

Researchers use intermittent vacuum deposition to increase OLED device performance

Researchers from Japan's Chiba University developed a new method to deposit thin OLED layers that achieves controllable molecular arrangement - that can be used to increase the efficiency and lifetime of OLED devices.

The method, called intermittent deposition, uses pauses in deposition and changes in deposition conditions to invert the orientation of the organic molecules, thus achieving high control over the resulting films. The researchers built on a tool called Rotary Kelvin Probe (RKP) that is used to measure the surface potential during and after the deposition in real-time. The new approach of intermittent deposition created a relaxed and stable surface layer with controllable polarization. 

Read the full story Posted: Jan 18,2024

Researchers from the University of Michigan develop a stable and efficient phosphorescence blue OLED using polariton-enhanced Purcell effects

Researchers from the University of Michigan developed a new OLED emitter system, based on a blue phosphorescence emitter, based on the polariton-enhanced Purcell effect. This new emitter systems offers high stability and high efficiency. 

The basic idea is to start with a light-blue (cyan) phosphorescence emitter (which offers a longer lifetime than a deep blue emitter), and placing it between two mirrors. The distance between the mirrors is controlled so that only deep blue light waves persist and are emitter from the mirror chamber. The researchers also tuned the optical properties of the OLED stack to the adjacent metal electrode which introduced a new quantum mechanical state called a plasmon-exciton-polariton, or PEP. This new state allows the organic material to emit light very fast, thus even further increasing the lifetime by decreasing the opportunity for excited states to collide and destroy the light-emitting material.

Read the full story Posted: Dec 21,2023