| 학회 | 한국재료학회 |
| 학술대회 | 2014년 가을 (11/27 ~ 11/28, 대전컨벤션센터) |
| 권호 | 20권 2호 |
| 발표분야 | F. 광기능/디스플레이 재료(Optical Functional and Display Materials) |
| 제목 | Highly Enhanced Upconversion Luminescence of NaYF4:Yb3+/Er3+ Nanocrystals through Gap Surface Plasmon Resonance |
| 초록 | Metal-insulator-metal (MIM) nanostructure has been much studied to confine the electromagnetic field through exciting gap surface plasmon in the spacer between metal layers. The gap surface plasmon resonator consisting of the nanostructured MIM layers is able to extremely enhance the absorption of the electromagnetic field. Here, we study the enhancement of upconversion luminescence (UCL) by the plasmonic MIM nanostructure. The UCL is a nonlinear process to emit photons of higher energies as a result of absorbing photons of lower energies. [1-3]. Different from another nonlinear process, the UCL can be induced by using an incoherent light source, thereby providing possibility to improve the performance of optoelectronic devices. Hexagonal phase NaYF4:Yb3+/Er3+ is most efficient upconverting material. In NaYF4:Yb3+/Er3+ nanocrystals, electrons of the Yb3+ at a lower energy level are excited to a higher energy level by absorbing near-infrared light, and then the excited electrons of Yb3+ are stabilized through energy transfer to Er3+ ions. Finally, visible light is emitted as a result that the Er3+ electrons are stabilized. However, most of the upconverting materials still remain quite low quantum efficiency. In this study, we experimentally and numerically verify that the UCL of β-NaYF4:Yb3+/Er3+ nanocrystals can be highly enhanced by the plasmonic MIM nanostructures. The pattern type, shape and size of the metal nanostructure as well as the insulator thickness in the MIM structure were controlled to optimize the UCL. Compared to the UC nanocrystals on a glass substrate, the MIM nanostructure exhibited over 500-fold enhancement in the UCL. From the finite-difference time-domain (FDTD) simulation and time-resolved photoluminescence (TRPL) measurement, it is believed that the enhanced UCL arises from the enhancement of local near-field and a change in the transition rates, as well as large scattering of the excitation wavelength, owing to the gap plasmon resonance and the localized surface plasmon resonance induced from the MIM structure. [1]. M. Haase and H. Schäfer, Angew. Chem., Int. Ed., 2011, 50, 5808 [2]. J. Shen, Y. Zhu, C. Chen, X. Yang and C. Li, Chem. Commun., 2011, 47, 2580 [3]. S. Schietinger, T. Aichele, H.-Q. Wang, T. Nann and O. Benson, Nano Lett., 2010, 10, 134 |
| 저자 | 고형덕1, 이기용1, 장호성2, 고두현1, 한일기1 |
| 소속 | 1한국과학기술(연), 2연세대 |
| 키워드 | upconversion; plasmon |
