August 13, 2014
By a News Reporter-Staff News Editor at Journal of Engineering — A patent by the inventors Cho, Sung-Hwan (Yongin, KR); Kim, Hyo-Seok (Yongin, KR), filed on February 28, 2011, was published online on July 29, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.
RE: Patent number 8790958 is assigned to Samung Display Co., Ltd. (Giheung-Gu, Yongin, Gyeonggi-Do, KR).
The following quote was obtained by the news editors from the background information supplied by the inventors: “The present invention relates to an organic light emitting device and, more particularly, to an organic light emitting device having a quantum dot light emitting layer, and a method of fabricating the organic light emitting device.
“The external quantum efficiency of an organic light emitting device can be expressed by the product of the internal quantum efficiency and the outcoupling efficiency of the organic light emitting device. The internal quantum efficiency of an organic light emitting device depends on the formation probability of emissive excitons. When electrons and holes are recombined, triplet-state excitons and singlet-state excitons are generated in a ratio of 3:1 due to the difference in spin multiplicity of electron spins. Therefore, phosphorescent and fluorescent materials have internal quantum efficiencies of 75% and 25%, respectively.
“Phosphorescence is used in a limited manner for manufacturing organic light emitting devices due to its short lifetime, and in most cases, organic light emitting devices are manufactured using fluorescent materials, thereby raising questions regarding the inefficiency of the organic light emitting devices. Therefore, there is a need to develop a nano-scale device that can generate a quantum effect in order to increase the optical efficiency of organic light emitting devices.”
In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors’ summary information for this patent: “To address the above and/or other problems, the present invention provides a quantum dot organic light emitting device having increased optical efficiency.
“The present invention also provides a method of manufacturing a quantum dot organic light emitting device having increased optical efficiency.
“According to an aspect of the present invention, there is provided an organic light emitting device comprising: a substrate; a first electrode layer formed on the substrate; a plurality of quantum dot structures, each having an organic light emitting layer on the first electrode layer; and a second electrode layer formed on the quantum dot structures.
“Each of the quantum dot structures may have a stack structure in which a hole transport layer, a light emitting layer, an electron transport layer, and a first metal layer are sequentially stacked.
“Each of the quantum dot structures may have a stack structure in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a first metal layer are sequentially stacked.
“According to an aspect of the present invention, a method of manufacturing an organic light emitting device comprises: forming a first electrode layer on a substrate; forming a block copolymer film that can cause phase separation on the first electrode layer; phase-separating the block copolymer film into a plurality of first domains, each having a nano size column shape, and a second domain that surrounds the first domains; forming a quantum dot template film of the second domain which comprises a plurality of nano size through holes by selectively removing the first domains; and forming quantum dot structures, each of which comprises an organic light emitting layer in the through hole of the quantum dot template film.
“The block copolymer film may be selected from block copolymers of polystyrene (PS) and polyvinylpyrrolidone (PVP). The phase-separating of the block copolymer film may comprise heating or pressing the block copolymer film. The selective removal of the first domains may comprise irradiating ultraviolet rays or wet etching on the block copolymer film.
“The forming of the quantum dot structures may comprise forming a stack structure in which an organic hole transport layer, an organic light emitting layer, an organic electron transport layer, and a first metal layer are sequentially stacked, or may comprise forming a stack structure in which an organic hole injection layer, an organic hole transport layer, an organic light emitting layer, an organic electron transport layer, an organic electron injection layer, and a first metal layer are sequentially stacked.
“The forming of the first metal layer may further comprise forming a second electrode layer on the quantum dot structures and the quantum dot template film by extending the first metal layer on the quantum dot template film from the quantum dot structures.”
URL and more information on this patent, see: Cho, Sung-Hwan; Kim, Hyo-Seok. Quantum Dot Organic Light Emitting Device and Method of Fabricating the Same. U.S. Patent Number 8790958, filed February 28, 2011, and published online on July 29, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8790958.PN.&OS=PN/8790958RS=PN/8790958
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