| 초록 |
Local surface plasmon resonance (LSPR), which is generated by the interaction between light and electron plasma waves at a metal/dielectric interface, has attracted both scientific and practical interest for emerging applications of nanoscale metal/oxide heterostructures which can be variously utilized for photocatalysis, enhanced solar cells, and light emitting diodes (LEDs). The crucial optoelectronic application of LSPR at the metal/oxide heterointerface is to improve solar light absorption and UV light emission by inserting nanoparticles (NPs) that promote light scattering and concentration. In this presentation, we demonstrate that the heterointerface of a ruthenium dioxide (RuO2) NP/ZnO nanorod hybrid shows dual enhancement of UV light emission and visible light absorption. The superior properties of ZnO and RuO2 for optical applications make these materials ideal for hybrid LSPR nanostructures. ZnO with a wide bandgap (3.37 eV) has been extensively studied due to its excellent chemical/electrical/optical properties. In particular, ZnO is an important material for nanoscale functional devices, which require a high surface area-to-volume ratio, due to its ease of growth and control of nanostructure morphology. RuO2 is of a great interest as a promising candidate for electrodes in capacitors and optoelectronic devices due to its semi-transparency, extremely low resistivity and excellent chemical and thermal stability. In order to take advantage of these superior properties of ZnO and RuO2 in nanoscale sizes, submetallic RuO2 NP/ ZnO nanorod hybrids were fabricated by an atomic layer deposition (ALD) method, which is highly compatible with current solar cell and LED fabrication technologies. The size and compositional control of RuO2 NPs yields (i) a coherent enhancement of visible light absorption (400% increase) via the SPR effect and intraband transition between partially filled Ru 4d states in RuO2 NPs and (ii) proper interfacial electronic alignment of RuO2/ZnO to allow SP mediated UV light emission (100% increase). The mechanism for SPR mediated UV emission is explained by a coupling between photo-induced carrier doping and radiative recombination enhancement proven by time-resolved photoluminescence analysis. Therefore, this study reports a meaningful technical advance in the application of LSPR to the sophisticated design of a nanostructure heterointerface, which enables dual SPR functionality for light harvesting and emission with a submetallic oxide NP and not a purely metal NP. |
