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[주간세미나] 2015년 12월 14일
관리자 2015-12-02

<채희엽 교수 Lab.>

* 발표자 : 정재학

* 제목 : Electrospray Deposition Process for Quantum Dot Multilayers of White Light Emitting Diodes

* 내용 : The first white QD-LED was conducted by the Li. Y. Q et al group using quantum dots. Most of the white-LED has been studied as a way to mix the QD about emitting layer (EML) by spin coating or micro-contact printing process. But there are inefficient energy transfers by generating non-radiative recombination in the mixed QDs layer. To solve this problem, a stacking type white-QDLED was introduced by kim et al in 2013. They use ‘dry pick-and-place transfer’ method for stacking of blue, green and red quantum dots sequentially. So, they could reduce inefficient energy transfer and implement the pure white light emission in the B/G/B/R system. But, transfer printing is a very difficult process and there are several issues such as severe waste of material and time.
In this study, we present to method of electrospray deposition (ESD) that can be greatly reduced processing time, less waste of material (<10%) and even have no use for orthogonal solvent for stacking QDs because the electrospray is almost dry mode. The dispersion of nanoparticles using electrospray prevents the aggregation and can fabricate thin film having a flat surface. So, applying this method to EML of the QD-LED, we were able to process whole solution (except cathode, Al) and continuous deposition for multilayers of white QD-LED.

* 발표자 : 정수빈

* 제목 : Dispersion of Quantum Dots in Polymer Matrix

* 내용 : Quantum Dots (QDs) has been used in various fields with its luminescence property. Furthermore, researches on quantum dots represent that QDs have high quantum yield, narrow full width half maximum, high color purity and tunable emission wavelength. Since this properties, QDs are applicable in display field for improving wide color gamut and high color purity. But synthesis of QD-polymer film by casting method, it has some problem with photoluminescence (PL) quantum efficiency. When we make a film by casting, the PL efficiency is decreased due to QD aggregation. The aggregation caused many problem such as forster resonance energy transfer (FRET) and contact energy transfer. For solving this problem, I reported a new method for monodispersing QD. Through electrospray method, QD-polymer beads are fabricated and it is shown well dispersion.
[주간세미나] 2015년 12월 7일