Plasmonic Enhancement for Colloidal Quantum Dot Photovoltaics

• Main Author: Paz-Soldan, Daniel Alexander
• Other Authors: Sargent, Edward H.
• Language: en_ca
• Published: 2013
• Subjects: photovoltaics; colloidal quantum dots; plasmonics; 0544
• Online Access: http://hdl.handle.net/1807/35660

Colloidal quantum dots (CQD) are used in the fabrication of efficient, low-cost solar cells synthesized in and deposited from solution. Breakthroughs in CQD materials have led to a record efficiency of 7.0%. Looking forward, any path toward increasing efficiency must address the trade-off between short charge extraction lengths and long absorption lengths in the near-infrared spectral region. Here we exploit the localized surface plasmon resonance of metal nanoparticles to enhance absorption in CQD films. Finite-difference time-domain analysis directs our choice of plasmonic nanoparticles with minimal parasitic absorption and broadband response in the infrared. We find that gold nanoshells (NS) enhance absorption by up to 100% at λ = 820 nm by coupling of the plasmonic near-field to the surrounding CQD film. We engineer this enhancement for PbS CQD solar cells and observe a 13% improvement in short-circuit current and 11% enhancement in power conversion efficiency.