유전재료와 후면전극에 따른 저전력 소비형 AC Powder EL 소자 제조 및 광전기적 특성

이강렬,박성,Lee, Kang-Ryeol,Park, Sung 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.2

AC powder EL 소자를 절연층의 유전재료와 후면전극의 전기비저항을 변화시켜 스크린 프린팅법으로 제조하였다. 제조된 소자의 광전기적 특성을 평가하기 위하여 인가 전압은 50∼300 $V_{rms}$까지 변화시켜 휘도 및 전류밀도를 측정하였다. 주파수 및 전압공급원은 정현파 발생 장치로서 frequency generator를 이용하였다. 휘도는 luminometer 의해 측정되었으며 전류밀도 측정을 위하여 multimeter를 사용하였다. 또한 유전층에 대한 유전율을 후막 제조 후 impedance analyser(HP 4194 A)를 이용하여 측정하였다. $TiO_2$ 분말을 $BaTiO_3$에 첨가함에 따라 유전율의 향상으로 초저가형 AC powder EL 소자의 유전층에 적용함으로써 거의 비슷한 전류밀도 하에 50 cd/$m^2$ 정도의 향상된 휘도를 얻을 수 있었다. 저전력 소모형 AC powder EL 소자의 유전층에 적용시 상용분말을 이용한 경우보다 용액 연소법에 의해 제조된 $BaTiO_3$ 분말을 이용한 경우가 더욱 향상된 85 cd/$m^2$ 정도의 휘도를 얻을 수 있었다. 또한 후면전극의 전기 비저항을 조절함으로써 AC powder EL 소자의 휘도는 비교적 감소하지만 전류밀도를 낮출 수 있었다. AC powder EL devices were fabricated by screen printing method with the dielectric materials in insulating layer and the electrical resistivity of rear electrode. Brightness and current density were measured at voltage range of 50∼300 $V_{rms}$ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Brightness and current density were measured by luminometer and multimeter. Also, dielectric constant for dielectric layer was measured by impedance analyser after preparing thick film. Dielectric constant was improved with amount of $TiO_2$ to $BaTiO_3$ powder. By applying such a process to dielectric layer of low cost AC powder EL device, brightness was improved to 50 cd/$m^2$ at similar current density. Dielectric constant $BaTiO_3$ powder by solution combustion process is better than commercial $BaTiO_3$ powder. By applying to that of low power consumption AC powder EL device, brightness was improved to 85 cd/$m^2$. Brightness of AC powder EL device was relatively decreased by control of electrical resistivity of rear electrode, current density was also decreased.

LCD 백라이트를 위해 스크린 프린팅법으로 제조된 AC Powder EL 소자의 유기결합제와 막두께가 광전기적 성질에 미치는 영향

이강렬,박성,Lee, Kang-Ryeol,Park, Sung 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.12

고효율 AC powder EL 소자를 초저가형과 저전력 소모형으로 분류하여 막의 두께와 제조된 유기결합제에 따라 스크린 프린팅법으로 제조하였다. 제조된 소자의 광전기적 특성을 평가하기 위하여 인가 주파수는 400Hz~1kHz, 인가 전압은 50~300 $V_{rms}$까지 변화시켜 휘도 및 전류밀도를 측정하였다. 주파수 및 전압공급원은 정현파 발생 장치로서 frequency generator를 이용하였다. 또한 휘도는 luminometer 의해 측정되었으며 전류밀도 측정을 위하여 multimeter를 사용하였다. 초저가형 AC powder EL 소자의 경우에는 가소제를 첨가하지 않고 발광층의 두께는 45~50$\mu\textrm{m}$이며 유전층의 두께는 약 10$\mu\textrm{m}$에서 43cd/$m^2$ 정도의 휘도와 20$\mu$A/$cm^2$정도의 전류밀도를 얻을 수 있었으며 저전력 소모형 AC powder EL 소자의 경우에는 15wt의 가소제 첨가하에 발광층의 두께는 45~50$\mu$m이며 유전층의 두께는 15~20$\mu$m에서 74cd/ $m^2$정도의 휘도와 30~40$\mu$A/ $m^2$정도의 전류밀도를 얻을 수 있었다. 또한 수명시간에 있어서 본 연구에서 제조한 AC powder EL 소자가 타사 제품보다 절대적으로 우수한 특성을 보였다.다. The high efficient AC powder EL devices classified by low cost and low power consumption type fabricated using screen printing method with film thickness and organic binder. Brightness and current density were measured at frequency range of 400Hz∼1kHz and voltage range of 50∼300V$\_$rms/ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Also brightness and current density were measured by luminometer and multimeter. In the case of low cost type AC powder EL device, brightness and current density were about 43 cd/m$^2$and 20$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m under no addition of plasticizer respectively. In the case of low power consumption type AC powder EL device, brightness and current density were about 74 cd/m$^2$and 30∼40$\mu$A/cm$^2$when the thickness of phosphor and dielectric layer was 45∼50$\mu$m and 15∼20$\mu$m under addition of 15wt% plasticizer respectively. Also, AC powder EL device fabricated in this study showed absolutely excellent characteristics as the lifetime was longer than products of other company.

Improvement of Hybrid EL Efficiency in Nanoparticle EL Devices by Insertion of the Layers of PVK and BaF2

이준우,김상식,조경아,김성현,Hyunsuk Kim,Byoungjun Park 한국전기전자재료학회 2005 Transactions on Electrical and Electronic Material Vol.6 No.3

Electroluminescence(EL) and current-voltage(I-V) characteristics of hybrid EL devices containing Pr and Mn co-doped ZnS nanoparticles were investigated in this study. For the insertion of a hole transport layer of poly (N-vinyl carbazole)(PVK), the current level became lower due to the accumulation of electrons at the interface between PVK and nanoparticles. When both PVK and buffer layer BaF2 were simultaneously introduced, the enhanced EL efficiency and improved I-V characteristics were obtained. This results from the additional increase of hole injection owing to the internal field induced by the significant accumulation of electrons at the interface. The presence of buffer layer BaF2 together with PVK makes it possible the charge accumulation enough to induce the sufficient internal field for further hole injection.

Improvement of Hybrid EL Efficiency in Nanoparticle EL Devices by Insertion of the Layers of PVK and BaF₂

Lee, Jun-Woo,Cho, Kyoung-Ah,Kim, Hyun-Suk,Park, Byoung-Jun,Kim, Sang-Sig,Kim, Sung-Hyun The Korean Institute of Electrical and Electronic 2005 Transactions on Electrical and Electronic Material Vol.6 No.3

Electroluminescence(EL) and current-voltage(I-V) characteristics of hybrid EL devices containing Pr and Mn co-doped ZnS nanoparticles were investigated in this study. For the insertion of a hole transport layer of poly (N-vinyl carbazole)(PVK), the current level became lower due to the accumulation of electrons at the interface between PVK and nanoparticles. When both PVK and buffer layer $BaF_2$ were simultaneously introduced, the enhanced EL efficiency and improved I-V characteristics were obtained. This results from the additional increase of hole injection owing to the internal field induced by the significant accumulation of electrons at the interface. The presence of buffer layer $BaF_2$ together with PVK makes it possible the charge accumulation enough to induce the sufficient internal field for further hole injection.

Luminance Characteristics of a Novel Red-Light-Emitting Device Based on Znq2 and Dye

Cho, min-Jeong,Park, Wan-Ji,Lee, Jeong-Gu,Lim, In-Su,Lim, Kee-Joe,Kim, Hyun-Hoo The Korean Institute of Electrical and Electronic 2002 Transactions on Electrical and Electronic Material Vol.3 No.2

In this study, a novel red emitting organic electroluminescent (EL) device was fabricated with the bis(8-oxyquinolino)zinc II (Znq2) doped dye as an emitting layer. The Znq2 was synthesized successfully from zinc chloride (ZnC1$_2$) as an initial material. Then, we fabricated the red organic EL device with a dye (DCJTB) doped and inserted Znq2 between emission layer and cathode for increasing EL efficiency. The hole transporting layer is a N,N'-diphenyl-N,N'-bis-(3-methylphenyl)-1,1'-diphenyl-4,4-diamine (TPD), and the host material of emission layer is Znq2. And the electrical and luminance characteristics of the device were measured. We found that the EL device with Znq2 inserting layer results in the increasing luminance efficiency.

Luminance Characteristics of a Novel Red-Light-Emitting Device Based on Znq2 and Dye

Min-JeongCho,Wan-JiChoi,Jeong-GuLee,Min-SuLim,Kee-JoeLim,Hyun-HooKim 한국전기전자재료학회 2002 Transactions on Electrical and Electronic Material Vol.3 No.2

In this study, a novel red emitting organic electroluminescent (EL) device was fabricated with the bis(8-oxyquinolino)zinc II (Znq2) doped dye as an emitting layer. The Znq2 was synthesized successfully from zinc chloride (ZnCl2) as an initial material. Then, we fabricated the red organic EL device with a dye (DCJTB) doped and inserted Znq2 between emission layer and cathode for increasing EL efficiency. The hole transporting layer is a N,N’-diphenyl-N,N’-bis-(3-methylphenyl)-1,1’-diphenyl-4,4-diamine (TPD), and the host material of emission layer is Znq2. And the electrical and luminance characteristics of the device were measured. We found that the EL device with Znq2 inserting layer results in the increasing luminance efficiency.

Felisberto Hernández y el relato pendiente: el proceso narrativo en El caballo perdido

( Carlos Fernández González ) 한국스페인어문학회(구 한국서어서문학회) 2020 스페인어문학 Vol.0 No.96

This article aims to analyze a very particular plot device, the narrative techniques used by Felisberto Hernández in the construction of one of his most best-known stories: El caballo perdido (1943). The focus is placed on the deliberate delay, interruption and fragmentation of the narrative process which inexorably turns against the traditional plot progression. The relative importance of the story, the child’s perspective in the narrative elaboration, the role of the secrets in the plot, the complexity of the character-narrator, and the writing of the otherness are also explored in detail.

발광층의 성장속도가 SrS:Ce EL 소자의 특성에 미치는 영향

이상태(Sang-Tae Lee),이홍찬(Hong-Chan Lee) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.10

To investigate the influence of phosphor growth rate on electrical and optical characteristics of SrS:Ce EL devices, SrS:Ce phosphor layers are deposited at growth rates of l7㎚/min and l50㎚/min. The devices with lower rates show the good crystallinity and high L-V characteristics.

Synthesis and EL Properties of Blue Light-emitting Poly(arylenevinylene)s

Hwang, Do-Hoon The Korean Infomation Display Society 2002 Journal of information display Vol.3 No.1

A series of fully conjugated polymers containing new arylenevinylene units were synthesized and their light-emitting properties were investigated. A bisphosphonate containing tetraphenyl group was made to react with three different dialdehyde monomers to produce fully conjugated alternating copolymers. The photoluminescence (PL) and the electroluminescence (EL) peak wavelengths of the polymers were varied from 500 nm to 460 nm depending on the polymer structure. Single layer EL devices using the polymers as an emissive layer have been fabricated. The single layer EL devices became visible between 12-22 V and emitted blue light.

적층형 구조를 가지는 3 전극의 고분자 발광 트라이오드

박성흠,조신욱 한국물리학회 2012 새물리 Vol.62 No.6

We report a new architecture for a three-terminal device with two functions, light-emitting and switching. The various layers in the novel three-terminal device are fabricated by casting soluble conjugated polymers from solution. The light-emitting three-terminal device can be described as being comprised of two polymer light-emitting diodes connected back-to-back with an internal common electrode. When the bias voltage between the common buried electrode and the two outer electrodes is controlled, the device can be turned on/off, and the emission intensity can be modulated. 본 연구에서는 공액고분자를 이용하여 발광 기능과 스위칭 기능을 동시에하는 다기능의 3 전극 발광 트라이오드 소자를 개발하였다. 본 연구에서개발한 적층형의 3 전극 발광 트라이오드는 두 개의 고분자 다이오드가하나의 삽입 전극으로 결합되어 있는 구조로 되어 있으며, 소자를구성하는 전극이 세 개로 이루어져 있다. 이때 가운데 삽입된 전극은공통 전극으로 사용되며 양쪽 끝단의 전극은 각각 전자와 정공의주입층으로 사용된다. 그리고 본 발광 트라이오드는 양쪽 전극과 삽입된공통 전극간의 전압 조절을 통하여 발광을 스위칭 할 수 있을 뿐만아니라 발광 세기의 조절이 가능하다. 또한 본 연구에서 제작된 발광트라이오드는 용액 공정을 기반으로 하고 있어서 제조 공정이 매우간단하여 차세대 저가형의 다기능 소자로 응용될 수 있다.