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A facile method for flexible GaN-based light-emitting diodes

  1. Top of page
  2. A facile method for flexible GaN-based light-emitting diodes
  3. Device efficiency of organic light-emitting diodes: Progress by improved light outcoupling
  4. Molecular chirality at surfaces

Younghun Jung, Xiaotie Wang, Sung Hyun Kim, Fan Ren, Jihyun Kim, and Stephen J. Pearton

Lighting based on solid-state GaN light-emitting diodes (LEDs) is difficult to make flexible or wearable due to the rigidity of the substrate (∼200-300 μm thick). However, the thin film itself (less than 5 μm thick) that grows on the rigid substrate can be flexible due to its thinness. Jung et al. demonstrate GaN-based flexible LEDs on polyethylene terephthalate (PET) substrates. The process uses commercial LEDs on patterned sapphire substrates, laser lift-off (LLO), wet etching for additional surface roughening, and mounting of the freestanding LED on a PET substrate. Bright electroluminescence was observed under strain. The LLO process is currently applicable up to 6-inch GaN-based LEDs on sapphire. Therefore, the demonstrated method is highly practical and easily implemented in a manufacturing process to fabricate large-scale flexible GaN-based LEDs.

Phys. Status Solidi RRL (2012) DOI 10.1002/pssr.201206374

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Device efficiency of organic light-emitting diodes: Progress by improved light outcoupling

  1. Top of page
  2. A facile method for flexible GaN-based light-emitting diodes
  3. Device efficiency of organic light-emitting diodes: Progress by improved light outcoupling
  4. Molecular chirality at surfaces

Wolfgang Brütting, Jörg Frischeisen, Tobias D. Schmidt, Bert J. Scholz, and Christian Mayr

Organic light-emitting diodes (OLEDs) are efficient large-area light sources facing their market entry. Still, the enhancement of light outcoupling from the multi-layer thin film structures remains a major challenge. This Review Article introduces the working principles of OLEDs and gives an overview of ongoing efforts to improve their efficiency, in particular by extracting more light. As an example, the photograph shows a white OLED where light emission from trapped modes is enabled by a high-index prism.

Phys. Status Solidi A (2012) DOI 10.1002/pssa.201228320

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Molecular chirality at surfaces

  1. Top of page
  2. A facile method for flexible GaN-based light-emitting diodes
  3. Device efficiency of organic light-emitting diodes: Progress by improved light outcoupling
  4. Molecular chirality at surfaces

Karl-Heinz Ernst

Chirality deals with the handedness of things. It has consequences in many disciplines, including nuclear physics, pharmacology, fragrance chemistry and molecular biology. When molecules adsorb at surfaces, mirror symmetry breaking is a common phenomenon and installs therefore handedness to the adsorbate. This Review Article is a digest of principles of mirror symmetry breaking upon adsorption and gives a topical review of molecular chirality at surfaces. Many different aspects of adsorption and self-assembly of chiral and prochiral molecules in two-dimensional systems at surfaces are discussed.

Phys. Status Solidi B (2012) DOI 10.1002/pssb.201248188

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