Enhanced hot-carrier extraction in ultra-thin silver nanostructures through localized field enhancement for boosting photovoltaics efficiency
Journal
Journal of Physics D: Applied Physics
Journal Volume
58
Journal Issue
48
Start Page
485108
ISSN
0022-3727
1361-6463
Date Issued
2025-11-27
Author(s)
Lin, Hsin-Ting
Hsu, Wei-Cheng
Dong, Yao-Han
Chang, Ting-Kai
Weng, Han-Shi
Chiang, Po-Hsien
Cheng, Du-Ting
Abstract
Conventional photovoltaic energy conversion primarily relies on semiconductors, but the efficiency of single-junction solar cells (SCs) is fundamentally constrained by the Shockley–Queisser limit. Beyond this limit, alternative approaches have been proposed to utilize excess photon energy or sub-bandgap photons. Among them, metal–semiconductor Schottky junctions offer a distinct mechanism for photoelectric conversion, where energetic (hot) carriers generated in the metal can be injected across the barrier before thermalization to the Fermi-energy level or below. This plasmonic-assisted or hot-carrier driven mechanism differs from the traditional hot-carrier SC concept that aims to suppress thermalization losses within semiconductors. In this study, we show that Ag metal, with its zero bandgap, can directly convert solar energy below the Si bandgap into electricity. By employing an ultra-thin Ag layer to overcome the extremely short hot-carrier lifetime, inverted pyramid structures to enhance light absorption, and a Schottky junction between Ag and Si to extract energetic carriers above the Fermi-energy level of metal, we achieve efficient electron–hole separation and current flow. Additionally, enhanced light intensity, up to 125 780 times using metallic nanostructures, could significantly increase nonlinear hot-carrier extraction, providing valuable insights into solar energy and waste heat harvesting.
Subjects
hot carrier
localized surface plasmon resonance
nanoparticles
nanostructures
silicon photonics
solar cell
Publisher
IOP Publishing
Type
journal article