나노임프린트 방법을 이용한 2차원 금속산화물 나노입자 광결정층의 제조 방법 및 형광체 막의 효율 향상에 대한 연구

Abstract

Recently there has been growing interest in the use of Y2O3:Eu3+ thin-film phosphors (TFPs) in flat panel displays (FPD) such as field-emission displays (FED), and plasma display panels (PDP) due to their superiority over the powder phosphors, such as thermal stability, reduced out-gassing, improved uniformity, and better adhesion to substrates. Two-dimensional (2D) photonic crystal layers (PCLs) have been applied to various light emitting devices incorporating thin-film luminescent materials in an attempt to enhance their extraction efficiency. In this study, a solution-based material process (sol-gel coating process) has been used to produce Y2O3:Eu3+ TFPs and a facile patterning method (reversal nano-imprint process) have been employed to produce 2D metal oxide (SiO2, TiO2) nanoparticle PCLs on Y2O3:Eu3+ TFPs. Reversal nano-imprint process is considered one of the most reliable processes for fabricating sub-micrometer sized patterns with simple, high throughput and low cost. The Y2O3:Eu3+ TFPs were prepared by Pechini-type sol-gel reactions and spin-coating. The polyurethane acrylate (PUA)/polydimethylsiloxane (PDMS) nano-imprint stamp was replicated from a master mold that was patterned using nanosphere lithography (NSL). The PUA hard stamp was then imprinted into the substrate with a pressure of 10 atm at 100°C for 35 min. The sizes of the metal oxide (SiO2, TiO2) nanoparticle used in patterning 600nm pitch were 10~20 nm. The pitch, diameter, and height of the PCL patterns were 600nm, 400nm, and 170nm, respectively. We compared the enhancement factor of photoluminescence efficiency by 2D photonic crystals with various metal oxide nanoparticle. The extraction efficiency of Y2O3:Eu3+ TFPs with nanoparticle PCLs of SiO2, TiO2 was approximately 2.52, 3.43 times higher than that of the Y2O3:Eu3+ TFPs, respectively.