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Journal Article
Microlens Encapsulation of Thixotropic Siloxane/Silica Nanocomposites for Highly Efficient and Reliable Micro‐Light‐Emitting Diodes
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- Authors
- Byung Jo Um, Hyungshin Kweon, Jiho Joo, Seung‐Mo Kang, Seungwan Kim, Gwang‐Mun Choi, Chanmi Lee, Yong Sung Eom, Kwang‐Seong Choi, Junho Jang, Byeong‐Soo Bae
- Issue Date
- 2024-12
- Citation
- ADVANCED OPTICAL MATERIALS, v.12, no.34, pp.1-9
- ISSN
- 2195-1071
- Publisher
- WILEY-V C H VERLAG GMBH
- Language
- English
- Type
- Journal Article
- Abstract
- Encapsulating materials for light-emitting diodes (LEDs) with optical-grade polymeric resin is essential to protect from external environments and to improve light-extraction efficiency (LEE) in micro-scale LED (µ-LED). In addition, the formation of microlens can further enhance the optical performance of µ-LED. However, previously developed materials have limitations due to a lack of rheological properties and thermal stability. Here, the fabrication of sol–gel derived phenyl siloxane hybrid (PSH) that has a high refractive index (n), for use as an encapsulating material for µ-LEDs is reported. Fumed silica nanoparticles (FSNs) are mixed with the PSH to yield siloxane/silica nanocomposites that have thixotropic properties, which enable the formation of microlens arrays. Optimizing the concentration of FSN in the nanocomposites yields a siloxane/silica nanocomposite that has a high n = 1.590 at 486 nm, high thixotropic index = 3.956, and increased optical haze (79.83% at 550 nm) makes light scattering. The use of PSH significantly increases the LEE of the LED (124.6% increase compared to an LED that does not use it). Finally, the siloxane/silica nanocomposite is used to direct-dispense microlenses on µ-LEDs in arrays. The encapsulation strategy can increase both the LEE and reliability of µ-LEDs.
- KSP Keywords
- Extraction efficiency(EE), High refractive index, Highly efficient, Micro-scale, Microlens array, Optical performance, Polymeric resin, Rheological properties, Silica nanocomposite, Thixotropic index, Thixotropic properties