Flexible Organic Light Emitting Diodes on Plastics

Printed Organic Electronics has expanded into a variety of applications and has already brought innovations to our lives. One of these promising devices are the Organic Light-Emitting Diodes (OLEDs), that are widely considered as the next generation light source, thanks to their cost-efficient printing manufacturing processes in combination with specific features, such as small film-thicknesses, lightweight, flexibility, high color-brilliance and low power consumption.

Wet manufacturing processes of OLEDs

Polymer OLEDs consist of several organic compounds, sandwiched together between two charged electrodes and operate on the principle of converting electrical energy into light, phenomenon known as electroluminescence. In order to optimize OLED efficiency, correlating the polymer structure with the device performance is essential. With the proper stacking of the organic layers, these materials result in a device that can achieve the required high efficiency and long lifetime.

Schematic representation of the structure of the OLED devices (left) & representative Electroluminescence emission spectra (right)

As the low cost, printed & flexible OLEDs attract great interest, OET has expanded its activities in light and power management to energetic light emitting devices.

After having established a fundamental knowledge about processing various OLED materials from solution, in middle scale coating techniques, OET aims at roll-to-roll processes, which offer better choices for mass production of low-cost & competitive fully printed OLEDs.

    OET pioneers in this field by incorporating its perennial experience in R2R processing on flexible substrates and paves the way in the European community on flexible and printed OLED technology by leading in National and European R&I projects (i.e. SmartLine, Apollon).

     OET’s R&D group currently develops Blue, Green, Yellow and Red OLEDs, while concentrating its efforts in White emission OLEDs for outdoor lighting. Indicatively, a threshold operating voltage as low as 3V with a maximum luminance of above 1500 cd/m² is achievable.

    OLED Superior Characteristics

    Structural Characteristics

    • Thin (<1mm)
    • Flexible
    • Lightweight (<0.5kg/m²)
    • Low Production Cost
    • Custom shapes
    • Custom sizes
    • Easy Adaptation (Static & Portable Applications in Various Environments)
    • Production in large scale by R2R printing processes.

    Emission Characteristics

    • Variety in Color emissions
    • UV Free
    • Low Glare
    • Low Heat Generation
    • Eco-Friendly Lighting Sources
      (Organic Substances)
    • Eye-Friendly Surface Light Source
      (Absence of Hard Edged Shadowing)

    R2R Production for Large-Scale Manufacturing

    OET has expertise in materials processing, deposition and characterization for scalable manufacturing OLED devices. OET develops the Process Technology platform for the cost-efficient production of OLEDs by optimizing all the key parameters that affect the R2R printing processes, the lifetime and the OLEDs efficiency, such as ink modification, printing speed, drying conditions, morphology & phase separation, design and architecture, laser scribing, thin barrier films and encapsulation.

    Relevant Publications

    “High Efficiency Solution Processable Polymer OLEDs: Manufacturing and Characterization”, Submitted to Materials Today: Proceedings, 9/2019

    “Optical and structural characterization of terpolymer active materials for white OLEDs (WOLEDs)”, Submitted to Materials Today: Proceedings, 8/2019

    “Optical and structural characterization of blended active materials for white OLEDs (WOLEDs)”, Submitted to Materials Today: Proceedings, 8/2019

    “Optical characterization of efficient with selective red emission organic light-emitting diodes”, Submitted to Materials Today: Proceedings, 8/2019

    “Fabrication and Study of White‐Light OLEDs Based on Novel Copolymers with Blue, Yellow, and Red Chromophores”, Physica Status Solidi (RRL) – Rapid Research Letters 13(2) (2019). DOI: 10.1002/pssr.201800419

    “A comprehensive study of the optical properties of emitting polymers for efficient flexible OLED devices”, Physica Status Solidi (A) – Applications and Materials 213(11) (2016). DOI: 10.1002/pssa.201600651