9 January 2017

VerLASE awarded further patents in US and Japan for use of 2D materials in light sources

VerLASE Technologies LLC of Bridgewater, NJ, USA (which was spun off from technology development firm Versatilis LLC of Shelburne, VT, USA in 2013) says that it has been awarded US Patent No. 9,525,150 by the US Patent Office and Patent No. 6027970 by the Japan Patent Office, further extending its patent portfolio on the use of 2D semiconductor materials as the active light-emitting layer in LEDs, laser diodes and other optoelectronic devices.

The technology enables low-cost, novel electroluminescent devices that can be tailored to directly emit in any color in the visible spectrum, or in a mixed combination for white light at a desired color temperature, without phosphors or other color-converting media. Versatilis says it can challenge organic light-emitting diodes (OLEDs) in applications requiring smaller pixel sizes such as micro-displays for augmented reality (AR) and virtual reality (VR) applications, where OLEDs have difficulty achieving sufficient brightness with small pixels. Other applications include smaller displays of all kinds, ranging from wearables to smartphones and tablets, offering a practical way around some of the technical and cost hurdles pacing broader adoption of OLEDs, claims the firm.

Semiconducting 2D materials like graphene have captured much attention for their potential use in many applications. Such materials can be grown in crystalline layers weakly bound to each other, then be cleaved or exfoliated into extremely thin layers. VerLASE has been investigating photoluminescent quantum wells (QWs) made of 2D materials such as gallium selenide, gallium sulphide and tungsten disulfide, which can be made into highly efficient down-converting phosphors free of cadmium or other heavy metals.

Versatilis previously won a broad patent (US 9,035,344) covering the use of such 2D semiconductor materials as phosphors, analogous to quantum dots (QDs) but as QWs in a 'flat' or 2D aspect, which can also take the form of nano-platelets (NPLs). The firm then extended the work in a second patent (US 9,269,854) to the use of such 2D materials as electroluminescent layers in active devices. VerLASE says that the newly issued patents solidify its IP for 2D materials in such applications.

Independent research worldwide points to the advantages of 2D materials in a wide range of applications, notes the firm. Quantum wells of 2D semiconductor materials offer similar optical advantages to quantum dots (with narrower spectral characteristics, better colors and color saturation) but can be more efficient and offer much better thermal characteristics for better stability in many lighting, projector and display applications.

It can also be easier to work with such 2D materials in depositing the other layers needed to make active devices. The active layers can be exfoliated sheets of controlled thickness, with the other layers necessary to make them into devices added through chemical processes, or grown directly on an appropriate substrate. Depending on the specific chemistries used, such 2D semiconductors can even be grown directly on silicon, enabling the use of available silicon chip manufacturing infrastructure for low cost.

"The unique attributes of 2D materials enable low-cost electroluminescent devices, fulfilling the original QD vision with inorganic QWs," says Ajay Jain, chief technical officer and inventor of the technology. He adds that the same basic 2D semiconductor materials can also be used as gain media in lasers and other high-value electro-optical devices.

See related items:

VerLASE awarded US patent on 2D materials enabling downconversion of InGaN-based blue/violet emitters to any color

VerLASE extends patent portfolio in 2D semiconductor materials for light sources

Tags: 2D Nanocrystals

Visit: www.verlase.com