• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.65-65
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• 2015

In this talk, I will introduce two topics. The first topic is the polymer light emitting diodes (PLEDs) using graphene oxide quantum dots as emissive center. More specifically, the energy transfer mechanism as well as the origin of white electroluminescence in the PLED were investigated. The second topic is the facile synthesis of eco-friendly III-V colloidal quantum dots and their application to light emitting diodes. Polymer (organic) light emitting diodes (PLEDs) using quantum dots (QDs) as emissive materials have received much attention as promising components for next-generation displays. Despite their outstanding properties, toxic and hazardous nature of QDs is a serious impediment to their use in future eco-friendly opto-electronic device applications. Owing to the desires to develop new types of nanomaterial without health and environmental effects but with strong opto-electrical properties similar to QDs, graphene quantum dots (GQDs) have attracted great interest as promising luminophores. However, the origin of electroluminescence (EL) from GQDs incorporated PLEDs is unclear. Herein, we synthesized graphene oxide quantum dots (GOQDs) using a modified hydrothermal deoxidization method and characterized the PLED performance using GOQDs blended poly(N-vinyl carbazole) (PVK) as emissive layer. Simple device structure was used to reveal the origin of EL by excluding the contribution of and contamination from other layers. The energy transfer and interaction between the PVK host and GOQDs guest were investigated using steady-state PL, time-correlated single photon counting (TCSPC) and density functional theory (DFT) calculations. Experiments revealed that white EL emission from the PLED originated from the hybridized GOQD-PVK complex emission with the contributions from the individual GOQDs and PVK emissions. (Sci Rep., 5, 11032, 2015). New III-V colloidal quantum dots (CQDs) were synthesized using the hot-injection method and the QD-light emitting diodes (QLEDs) using these CQDs as emissive layer were demonstrated for the first time. The band gaps of the III-V CQDs were varied by varying the metal fraction and by particle size control. The X-ray absorption fine structure (XAFS) results show that the crystal states of the III-V CQDs consist of multi-phase states; multi-peak photoluminescence (PL) resulted from these multi-phase states. Inverted structured QLED shows green EL emission and a maximum luminance of ~45 cd/m2. This result shows that III-V CQDs can be a good substitute for conventional cadmium-containing CQDs in various opto-electronic applications, e.g., eco-friendly displays. (Un-published results).

• 유기물자원화
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• 제27권2호
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• pp.67-73
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• 2019

본 연구에서는 유기성폐자원의 바이오가스 생산 및 이용을 최적화를 위해 현장시설의 정밀모니터링과 시설별 에너지수지를 분석하고, 현장문제 해결방안에 대해서 조사하여 전처리시설 및 발전기 등의 설계 및 운전 가이드라인을 제시하였다. 고품질화 정제설비 운영에 잦은 고장 및 효율 저하를 해결하기 위해서는 가스전처리가 필요하며, 탈황, 제습, 탈실록산, 분진 처리, 휘발성유기화합물 등의 처리공정이 있다. 이 공정들은 고품질화 공정에서도 제거되는 물질들이기에 가스 전처리에서는 정량적 가이드라인은 제시하지 않고, 정성적 가이드라인으로 처리공간에 운영하도록 제시하였다. 특히, 분진, 실록산 및 휘발성유기화합물 등은 가스 전처리에서 제거되지 않으면 고품질화 공정의 잦은 고장의 주원인이된다. 바이오가스 고품질화 공정에 대한 설계 운전 가이드라인은 전체 가스 발생량의 90 % 이상 이용, 2계열화, 여유율 10 % 이상 감안 등이 있으며, 품질기준[메탄함량(프로판 포함) 95 % 이상]을 제시함. 또한 균등한 바이오가스 유입을 위해 가스균등조 설치, 보조연료 균등투입 제어를 위한 열량자동조절장치 설치, 가스압축과정에서 다량 발생하는 수분 제거를 위한 고품질화 후단의 제습장치 설치, 겨울철 설비의 결빙 및 효율 저하 방지를 위한 보온설비 설치, 특히 멤브레인 설비는 실내 설치 등을 제시하였다.