Lee Changhwan, Park Yujin, Park Jeong Young
Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science Daejeon 305-701 Republic of Korea.
RSC Adv. 2019 Jun 11;9(32):18371-18376. doi: 10.1039/c9ra02601k. eCollection 2019 Jun 10.
The use of metal nanoparticles, including Au, Ag, Cu, and Al, can increase the efficiency of photovoltaic devices by electromagnetic field enhancement, which is driven by the excitation of localized surface plasmon resonance. Direct energy conversion from light into electricity the decay of surface plasmons causing the excitation of hot electron-hole pairs is also a feasible channel. The generation of hot electrons in metal nanostructures can occur through intraband excitation within the conduction band or through interband transition, which is caused by transitions from other bands to the unoccupied conduction band states. Here, we show the distinction between hot electron generation induced by intraband excitation and interband transition on a plasmonic Cu/TiO nanodiode by measuring the current conversion efficiency with a monochromator system. We also show the dependence of the production of photocurrent on the thickness of the Cu layer and the effect of an aluminum oxide protection layer on the hot electron flux oxidation of the Cu layer. Our results can provide a better understanding for copper-based hot electron photovoltaics, which could lead to more efficient plasmonic energy conversion.
包括金、银、铜和铝在内的金属纳米颗粒的使用，可以通过局部表面等离子体共振激发驱动的电磁场增强来提高光伏器件的效率。从光直接转换为电能——表面等离子体的衰减导致热电子 - 空穴对的激发——也是一种可行的途径。金属纳米结构中热电子的产生可以通过导带内的带内激发或通过带间跃迁发生，带间跃迁是由从其他能带跃迁到未占据的导带态引起的。在这里，我们通过用单色仪系统测量电流转换效率，展示了在等离子体铜/二氧化钛纳米二极管上带内激发和带间跃迁引起的热电子产生之间的区别。我们还展示了光电流产生对铜层厚度的依赖性以及氧化铝保护层对热电子通量的影响——铜层的氧化。我们的结果可以为基于铜的热电子光伏提供更好的理解，这可能导致更高效的等离子体能量转换。
