Introduction
Established in 2009, UK-based SmartKem is a pioneering company in microLED displays. Besides their revolutionary TRUFLEX® technology that has the potential to significantly reduce manufacturing costs, this major player is bringing microLED technology to life for the next generation of displays, from TVs and laptops to the immersive world of AR/VR.
The company has also developed a new organic thin film transistor (OTFT) backplane. The integration of these OTFT backplanes with microLED enables the use of flexible materials such as a plastic substrate.
This in turn helped them break new ground with the world’s first monolithic microLED display, which guarantees high performance and energy efficiency in displays.
In this blog post, we explore how SmartKem’s technology can revamp the display market, especially microLEDs, through enhanced quality and performance.
SmartKem’s Breakthrough Innovations: OTFT Backplanes
Organic thin-film transistors (OTFTs) have been instrumental in improving microLED performance. SmartKem has made significant breakthroughs in this field. These backplanes are a critical component in the manufacture of next-generation display technologies, such as flexible and foldable displays.
Key Aspects of OTFTs
Let’s go through some of the key features of OTFTs here:
High-Performance
SmartKem’s OTFT backplanes exhibit high electron and hole mobility, enabling the fabrication of high-resolution, high-refresh-rate displays. These backplanes may outperform traditional amorphous silicon (a-Si) and low-temperature polycrystalline silicon (LTPS) technologies.
Scalable Manufacturing
The technology is designed for scalable, low-cost manufacturing using solution-processing techniques, such as inkjet printing and slot-die coating. This allows for the production of large-area displays at a lower cost compared to traditional vacuum-based deposition methods.
Flexibility and Conformability
The OTFT backplanes are inherently flexible and can be fabricated on plastic substrates, enabling the development of bendable, foldable, and rollable display products. This opens up new design possibilities for consumer electronics and wearable devices.
Low-Temperature Processing
Most importantly, the backplanes can be fabricated at low temperatures, typically below 150°C, making them compatible with a wide range of flexible substrate materials, including plastic and metal foils.
Commercialization Prospects
This OTFT backplane technology has been adopted by leading display manufacturers for the development of next-generation display products, including flexible OLED displays, e-paper, and other emerging display technologies.
The company’s technology has also been demonstrated in various prototypes and is currently in the process of commercialization.
Organic Last Integration (OLI) Technology
Smartkem has also developed an approach called Organic Last Integration (OLI) technology which allows the direct fabrication of OTFTs on microLEDs.
This will eventually overcome the limitations of high-temperature applications ie. >350°C. Because the use of high temperatures degrades microLED performance, SmartKem’s unique OTFT materials have revolutionized the manufacturing process.
The OLI technology offers advantages such as:
Low-Temperature Processing
Semiconductor inks by SmartKem can facilitate OTFT fabrication below 150°C. The integrity of microLEDs during manufacturing remains preserved in the process.
Structural Innovations
This technology provides thick polymer planarization layers and metal shielding, thereby protecting OTFTs from external light interference.
Enhanced Electrical Properties
OLI technology offers features like high currents, low leakage, and stability under stress and is key to achieving high-resolution microLED displays.
How It Works: The Chemistry Behind OTFTs
SmartKem’s technology is able to manufacture TFT backplanes directly on top of Gallium Nitride (GaN) microLEDs without the need for complicated mass transfer and laser welding procedures.
This is made possible with the help of formulated inks such as dielectric, semiconductor, planarizing, and surface treatment. These inks are applied using conventional coating procedures and subjected to processes like UV curing or hot plate baking. This ensures optimal performance. Here’s a rundown of the process:
1. Ink Formulation
The materials are made to be coatable inks, hence they are easy to use and incorporated into standard manufacturing procedures.
2. Device Structure
OTFT structures are composed of three electrodes (source, drain, and gate) on either glass or plastic substrates. These structures are similar to traditional conductors.
During the construction of these structures layers of liquid-coatable inks are used, thereby ensuring stability and robust performance.
3. Prototyping and Development
Prototyping and development are facilitated using industry-standard equipment. It allows for the integration of OTFT backplanes into existing amorphous silicon display lines with minimal changes.
Notable Advantages of SmartKem’s OTFT Backplanes
The development of OTFT technology represents a significant advancement in the field of printed and plastic electronics. Here are a few of its advantages:
1. High-Resolution Displays
The OTFT backplanes from SmartKem produce bright, uniform displays with high resolution.
2. Processing at Low Temperatures
Low-temperature processing is made possible by OTFT technology, which promotes affordable production and compatibility with flexible plastic substrates.
3. Flexible Fabrication Process
The fabrication of OTFT devices involves photolithography, i.e., the use of light to transfer a pattern onto a substrate. SmartKem’s technology uses dual-gate devices, which include both a back gate and a front gate. Their flexible method helps in the development of different device types simply by changing materials and design parameters.
4. Versatility of OTFT materials
The inks are sold in bottles like single cream, which are adaptable beyond transistors. They can be used for PCBs and stretchable components as well. The low processing temperature and photocurable nature of polymers enable diverse applications.
5. Adaptable usage
This innovative approach has a number of applications. For example, increasing the microLEDs’ efficiency across a wide range of display types and creating AR/VR screens with a high pixel density.
Real-World Applications and Future Potential
The future aspects of SmartKem’s latest technology promise great potential. Here are a few takes on the applications and future prospects:
1. Brightness and Pixel Precision
The OTFT has been able to achieve brightness levels above 100,000 nits and pixel spacing as narrow as 100 microns. More studies and innovations in this field promise brighter screens, setting new benchmarks for visual technology.
2. Transfer Sheets
OTFTs have accommodated both transfer sheets and LED source wafers, thus increasing the possibilities of a range of display requirements. Source wafers work best in applications requiring high pixel density and small screens. On the other hand, transfer sheets optimize microLED display efficiency across a broader range of display forms.
3. Optimizing Display Brightness
The ultimate brightness of microLED displays using this approach can reach up to 200,000 nits with larger pixel sizes. Optimized designs are showing potential for exceeding 500,000 nits, setting new benchmarks for display technology.
Final Note
The OTFT backplane technology from SmartKem has successfully been able to eliminate the complexity of conventional mass-transfer processes. This adds to a major advancement in display technology. It has paved the way for further advancements in visual technology.
In addition to offering remarkably steady, high-resolution, high-brightness displays, future display innovations may bring forth brighter and more efficient screens.