TW544950B - Light emitting diode having luminescent nano-particles - Google Patents

Abstract

The present invention provides a simple and cheap light emitting diode manufactured by colloidal luminescent particles, which uses colloidal oxide, semiconductor or polymer luminescent nano-particles of uniformly sized particle to manufacture a luminescent object with high-quality and narrow-bandwidth. The present invention utilizes colloidal luminescent nano-particles capable of being uniformly distributed in the liquid, and further uses a simple thin-film manufacturing process such as spraying, immersing or coating to uniformly process the nano-particles on a substrate of any shape and any kind, thereby manufacturing a cheap, large, repeatable and high-efficient luminescent object.

Description

544950 V. Description of the invention (1) Field of the invention: The present invention relates to a light-emitting diode, and more particularly to a light-emitting diode having light-emitting nano particles. Background of the Invention: In recent years, due to the progress of various epitaxial technologies, light emitting diodes (LEDs) can grow double heterostructures of good quality, and the internal quantum efficiency of LEDs can reach more than 90%. However, the light emitting layer (EL) of conventional light emitting diodes is generally formed by epitaxial growth, so the growth rate is slow. However, nano-particles or quantum dots can increase the density of electronic states (density state), thus increasing the luminous efficiency of the material. These small-sized luminescent nano particles can be chemically formed into nano-colloidal particles to uniformly disperse them, or they can also be epitaxially grown on the substrate of a semiconductor wafer (for example, GaAs). The chemically formed luminescent nanocolloidal particles have the following advantages: (1) can be mass-produced and dispersed in a solvent, as a solution; (2) can be applied by conventional coating methods such as spraying, dipping or spin coating . The coating method can instantly form a film on any substrate; (3) The speed can reach several micrometers per second (em / sec), which can increase the speed by a factor of 1,000 to form a high-density diode, and its area Limited only by the area of the substrate. The method of epitaxy, the choice of the substrate is very demanding, and it needs to have the properties of a lattice of coordinated sub-points', and its formation speed is very slow (for example, 544950 per page 4 V. Description of the invention (2) / J, hours micron · # M / hr), the density per unit area is very low, and vacuum equipment is required for the necessary processes. The method of photoexcitation has confirmed that the cadmium sulfide (CdS) quantum dots produced by the stupid crystal method have stimulated emission and optical gain. Object of the invention:

Therefore, the present invention provides a light-emitting nanocolloidal particle produced by a chemical method using an electrical excitation method to make it effectively emit light, and is used as a high-efficiency, low-cost, large-area light-emitting diode. The main object of the present invention is to provide a light emitting diode having light emitting nano particles. Another object of the present invention is to provide a low-cost light emitting diode. Another object of the present invention is to provide a large area light emitting diode.

Summary of the invention: The present invention provides a light-emitting diode with light-emitting nano-particles. The light-emitting diode includes at least a first electrode, which is conductive, and a substrate, which facilitates the growth of the light-emitting diode. Luminescent nanoparticles, luminescent nanoparticles, and

544950

The diode causes the emitter current to emit light through the light-emitting nanoparticle layer having the light-emitting nanoparticle. The detailed description is related to the preferred embodiments. The technology, means, and specific structural features adopted by the present invention to achieve the above-mentioned object, the preferred and feasible embodiments will be given, and will be further disclosed by not explaining the figures, as follows. Described.

Firstly, referring to FIG. 1A ', a light-emitting diode having light-emitting nano-particles, an endurance graph of 10 is not acceptable. Contains at least a first electrode (eiectrode) i2, :: conductive 'The first electrode may be an N-type electrode or a p-type electrode formed of a metal material'. For example, gold, silver, aluminum, or Magnesium forms the electrode 12; a substrate 11 such as a semiconductor 3 insulator is usually used as a semiconductor substrate to facilitate the growth of the light emitting diode; a luminescent nanopart 1c1es 13; The second electrode is electrically conductive, and the second electrode is different from the first electrode. For example, gold, silver, and aluminum can be used. 'The light-emitting nanoparticle semiconductor light-emitting nanoparticle molecular nanoparticle composed of nanoparticle particles each diameter 13' Between 5nm and 500nm

The second electrode 4 and 4 may be N-type electrodes or p-type electrodes (that is, electrodes), and are formed of a metal material, for example, or the electrode 14 is formed of magnesium. Furthermore, the j-substance is an oxide light-emitting nanoparticle such as a sulfide (C d S) particle, or higher. In a preferred embodiment, the light-emitting nanometer 5 light nano-particles 1 31 have a specific straightness, especially a light-emitting nanometer i less than 100 nm.

544950

Particles can have better luminous effect after cavities. In addition, the luminescent nanoparticle system is substantially uniformly dispersed to achieve high-efficiency light emission. Referring to FIG. 1B, a current flows through the light emitting diode 20 having the light emitting nano particles through the first electrode 21 and the second electrode 24, so that the light emitting nano particle layer 23 can emit light. The luminous nanoparticle provided by the present invention is a preferred and feasible embodiment. First, the method of Pietro ’s method was used to synthesize soluble cadmium sulfide (CdS) nano particles. Further, 0.80 g, 3.0 mm of cadmium acetate dehydrate was dissolved in a mixed solvent of 20 m 1 (in a preferred embodiment, the volume ratio was 1: 1: 2 in a mixed solvent of acetonitrile, methanol, and water) to form a first solution. Next, 0.36 g '1.5 mmole of disodium sulfide nanohydrate and p-hydroxy 1 thiophenol were also dissolved in another 20 ml 1 of the same mixed solvent (in the preferred The embodiment is dissolved in a mixed solvent of acetonitrile, methanol, and water with a volume ratio of 1: 1: 2 respectively to form a second solution. The first solution was mixed with the second solution, and the reaction was stirred vigorously at room temperature in the absence of light for 18 hours to form a reactant. The reaction product was centrifuged and washed with distilled water several times to obtain 0.7 g of yellow CdS nano particles, with a product protected by p-hydroxy thiophenol on the periphery. CdS nanocolloids were dissolved in ethanol to make a 1% (weight / volume) solution for spin coating. At this time, the nano particle size can be obtained.

544950 V. Description of the invention (5) ----- 5nm 〇 The light emitting diode system provided by the present invention is a preferred and feasible embodiment. The low-impedance (doping 1015 / cm3) wafer was sequentially washed with acetone, methanol, and deionized water, and then ultrasonically cleaned. The wafer was then placed on a spin coater and rotated at 4,000 rpm for 60 sec. The spin coater contains the cadmium sulfide nano particles obtained by the above-mentioned manufacturing method, and is divided into: (a) a few drops of cds nano solution, after spin coating, under low pressure (75mmHg), room temperature And dried for five minutes to form a first sample.

(2) After a few drops of the Cds nano solution is spin-coated, it is rapidly heated to 425 ° C under low pressure (75 mmHg) and dried for five minutes to form a second sample. (3) Spin-coat a few drops of a one-to-one (volume ratio) i% CdS nano solution and a 6% solution mixed with a 0.02 nanometer / grain liquid phase, then at low temperature (75 mmHg), Quickly warm to 425 1 and dry for five minutes to form a third sample.

After the transfer coating was completed, 3 nm of chromium (Cr) was evaporated on the top and bottom of the wafer, and then a gold (Au) film was evaporated to form a light transmission with an upper electrode (top electrode) of 10 nm. Sex electrode, and the bottom electrode of 15011111. Please refer to Figure 2. When the driving voltage is about 3V, the rectifying diode I-V curve of the light-emitting diode is shown in Figure 2. The first sample emits light at a wavelength of 5 2 6 · 5 nm (as shown in Figure 3a), while the wavelengths of the second and third samples (as shown in Figure 3 β and Figure 3C) move from 526 · 5 nm to 513 · 7 nm, and also emits light at 571 · 5 nm, which belongs to the addition of oxygen. It can be seen that the emission wavelength of 526 · 5nm will increase with the process temperature (room temperature increases to 425 ° c)

Page 8 544950, description of the invention (6) = reduced (513. 7nm), but the intensity will increase; in addition, if it is made in an environment containing oxygen, a new emission wavelength appears at 571.5 nm. The intensity can be increased by a factor of one hundred. The addition of oxygen not only adds one more emission wavelength, but also increases the luminous intensity by more than a hundred times. These changes are unusual and unpredictable in the conventional semiconductor light-emitting diodes. Therefore, a convenient adjustable frequency light-emitting body can be provided. The production also adds the light diode of the present invention, and the development of the diversity of the light emission wavelength is unlimited. Chemically formed luminescent nanocolloidal particles have several benefits:

(1) It can be mass-produced and dispersed in a solvent in a solution state; (2) A conventional coating method such as spraying, dipping or spin coating can be used. The coating method can instantly form a film on any substrate; (3) The speed can reach several micrometers per second (Vm / Sec), which can increase the speed by a thousand times to form a high-density, large-area diode, and its area Limited only by the area of the substrate. Therefore, the light emitting diode with light emitting nano particles of the present invention can reduce the manufacturing cost ^ and can produce a large area light emitting diode.

Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with the art can make some modifications and retouching without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application

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Claims (1)

544950 1 A light-emitting diode with light-emitting nano particles, comprising at least: a first electrode, which is conductive; a substrate, which grows the light-emitting diode; and a light-emitting nano-particle layer ( luminescent nanoparticies), and a second electrode, which is conductive; wherein a current flows through the first electrode and the second electrode through the light-emitting diode having the light-emitting nano particles, so that the light-emitting nano particle layer ^ With glow. 9 to 2. The light-emitting diode according to item 1 of the scope of patent application, wherein the light-emitting nano particles are essentially oxide light-emitting nano particles. ® 3 · The light-emitting diode according to item 1 of Shen Qing's patent scope, wherein the light-emitting nanoparticle is essentially a semiconductor light-emitting nanoparticle. 4. The light-emitting diode according to item 3 of the scope of the patent application, wherein the semiconductor light-emitting nanoparticle is a cadmium sulfide (CdS) nanoparticle. 5. The light-emitting diode according to item 1 of the scope of the patent application, wherein each of the light-emitting nano-particles in the light-emitting nano-particle layer has a specific diameter between 5 nm and 500 nm. 6. The light-emitting diode according to item 1 of the scope of the patent application, wherein the light-emitting nano-particles in the light-emitting nano-particle layer are substantially uniformly dispersed in the spring's light to achieve luminous efficacy of the south. 7. The light-emitting diode according to item 1 of the scope of patent application, wherein the substrate is a semiconductor. 8 · According to the light-emitting diode described in item 1 of the patent application scope, wherein Page 11 544950 4X VI. Scope of patent application Substrate insulator. 9 · The light-emitting diode according to item 7 of the scope of patent application; the diode, wherein the substrate is a silicon wafer. Wherein the MAI) wherein the Shao (A 1) 10. The first electrode of the light-emitting diode according to item 丨 of the scope of the patent application includes a material selected from the group consisting of gold Uu), silver (Ag), and lock (M g ) Group 1 1 · According to the scope of the patent application No. 丨 ^ The second electrode contains a material system] = the first diode described above and the money (Mg) two 4 gold (Au), silver (Ag) Page 12