Carbon nanotube induced enhancement of electroluminescence of phosphor

Abstract

Electroluminescence ͑EL͒ was observed on conventional cathodoluminescent ͑CL͒ phosphor with the incorporation of carbon nanotube ͑CNT͒ at ambient air. The role of CNT can be understood as enhancing the local electrical field, which allows electron injection to the active center of phosphor at relatively low operating voltages. In this EL device, the brightness of CL phosphor was significantly improved from no light emission in the case of no addition of CNT to 35 cd/ m 2 with 1 wt % CNT at 10 kHz of ac 300 V.

P.117: Orientation of Fillers in CNT/Polymer Composite Interfacial Layer for Enhancing Charge Transportation

“…Our result shows the local field increases with higher CNT loading which implies higher emission. Thus our result agrees with the literature reports [3,4,5].…”

“…The neighboring CNTs at each junction exert a local electric field E local thinning the tunneling barrier width and promoting the electron emission, which is given by, E local =βV/d (1). Here, V is the applied bias voltage, d is the intertube gap, and β is field enhancement factor determined by the aspect ratio of CNTs [5]. Using equation (1) we calculated the E local for varying CNT concentration shown in Fig.…”

“…Since the emission is intrinsically linked with the charge transportation [3] our study on local electric field behavior indicates the charge transportation efficiency of the composite material at different conditions of the CNTs. The results in the literature [3,4,5] already says that the incorporation of CNT composite interface layer and increase in CNT loading improves emission, but due to high production cost of CNTs the application remains limited. Our results reveal that by tailoring the filler alignment in the interfacial layer, we can obtain higher carrier injection and enhanced emission even at lower CNT loading, offering cost reduction of OLEDs and other optoelectronic devices.…”

“…The geometry of the CNTs helps to increase the local electric field, eventually allowing lower operating voltages and improved emission [4]. Generally in a CNT/polymer composite film, as the CNT loading increases, the number of tunneling junctions is increased, hence it enhances the transport of carriers [3,4,5] through the thin polymer layers between neighboring tubes via fluctuation induced tunneling (FIT) [6]. But due to the high production cost of CNTs, optimizing emission by increasing CNT mass fraction claims higher device cost.…”

Optical Properties of Graphene Doped ZnS:(Cu,Al) Inorganic Electroluminescence Devices by Screen Printing

“…AC 분산형 EL 소자는 투명전극이 형성된 투명한 기판 위에 발광층, 유전층, 배면전극 순으로 적층하여 제작된다. EL 소자의 휘도와 효율 향상을 위한 연 구가 지속적으로 진행되고 있으며, 특히 형광체를 첨가 재료 와 혼합하여 발광 특성을 향상시키기 위한 연구가 활발하게 이루어지고 있다 [3,4] . (1)과 같이 표현할 수 있다 [6] .…”