A light-emitting diode (LED) structure includes a light-emitting diode including an emissive electroluminescent layer situated between two electrodes, a light extraction layer (LEL) comprising a UV-cured ink, and a UV blocking layer between the LEL and the light-emitting diode. The UV blocking layer has a thickness of 50-500 nm and at least 90% absorption to UV light of wavelengths for curing the UV-cured ink.

Provided is a method for producing a π-conjugated polymer capable of suppressing an increase in dark current of an organic photoelectric conversion element even if the method includes a purification step including heating. A method for producing a π-conjugated polymer includes: step (I) of heating and dissolving a crude π-conjugated polymer in a solvent to obtain a polymer solution; and step (II) of precipitating a π-conjugated polymer from the polymer solution. In step (I), the content of peroxide in the solvent is 0.1% or less in terms of a relative area ratio measured by high-performance liquid chromatography, and the electron spin concentration of the π-conjugated polymer is 30×10.sup.16 Spin/g or less and/or 2.5 times or less the electron spin concentration of the crude π-conjugated polymer.

A light-emitting diode display including a substrate having a driving circuitry and a plurality of light emitting diode structures disposed on the substrate. Each light-emitting diode structure has a light emitting diode with a light emission zone having a planar portion, and a pigmentless light extraction layer of a UV-cured ink disposed over the light-emitting diode. The light extraction layer has a gradient in index of refraction along an axis normal to the planar portion, and the index of refraction of the light extraction layer decreases with distance from the planar portion.

The present invention provides a thermally activated delayed fluorescent material, a method for preparing the same, and an electroluminescent device including a compound consisting of a receptor A and a donor D, the compound having a molecular structure of D-A shown in Formula 1:
D-A   Formula 1 wherein the receptor A is selected from any one of the following structural formulas: ##STR00001## wherein R is selected from any one of the following structural formulas: ##STR00002## ##STR00003##
and the donor D is selected from any one of the following structural formulas: ##STR00004## ##STR00005##

An organic light-emitting diode (OLED) structure includes a stack of OLED layers; a light extraction layer (LEL) comprising a UV-cured ink; and a UV blocking layer between the LEL and the stack of OLED layers.

A composition which is useful for producing a light emitting device of which initial deterioration is suppressed and a light emitting device formed using the composition are described. The composition contains a host material and a guest material blended therein; the host material contains an aromatic compound having a condensed ring skeleton in which only three or more benzene rings are condensed, the guest material contains a compound having a heterocyclic group containing a carbon atom and at least one selected from a boron atom, a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom and a selenium atom in the ring, and the total amount of silicon atoms contained in the host material and in the guest material is over 0 ppm by mass and 28 ppm by mass or less with respect to the total amount of the host material and the guest material.

A composition which is useful for production of a light emitting device of which initial deterioration is suppressed, and a light emitting device formed using the composition, are provided. The composition contains a host material and a guest material blended therein. The host material contains an aromatic compound having a condensed ring skeleton in which only three or more benzene rings are condensed. The guest material contains an aromatic amine compound. The total amount of sodium atoms contained in the host material and sodium atoms contained in the guest material is 400 ppb by mass or less with respect to the total amount of the host material and the guest material.

The present application discloses a QLED manufacturing method including: providing a substrate provided with an electron transport layer; depositing a solution on a surface of the electron transport layer, standing until the electron transport layer is infiltrated, and then performing a drying operation, wherein the solution includes a main solvent and a solute dissolved in the main solvent, a polarity of the solute is greater than a polarity of the main solvent, and the solution is not able to dissolve the electron transport material in the electron transport layer; preparing other film layers on the electron transport layer processed by the mixed solvent to prepare the QLED, such that the QLED at least includes: an anode and a cathode arranged oppositely, a quantum dot light emitting layer arranged between the anode and the cathode, and the electron transport layer between the quantum dot light emitting layer and the cathode.

An organic light-emitting diode (OLED) structure includes a stack of OLED layers that includes a light emission zone having a planar portion, and a light extraction layer formed of a UV-cured ink disposed over the light emission zone of the stack of OLED layers. The light extraction layer has a gradient in index of refraction along an axis normal to the planar portion.

High-performance carbon nanotube (CNT) based millimeter-wave transistor technologies and demonstrate monolithic millimeter-wave integrated circuits (MMICs) based thereon, and methods and processes for the fabrication thereof are also provided. CNT technologies and MMICs demonstrate improved power efficiency, linearity, noise and dynamic range performance over existing GaAs, SiGe and RF-CMOS technologies. Methods and processes in CNT alignment and deposition, material contact and doping are configured to fabricate high quality CNT arrays beyond the current state-of-the-art and produce high performance RF transistors that are scalable to wafer size to enable fabrication of monolithic integrated circuits based on CNTs.