Plasmonic Nanocrystal Solar Cells Utilizing Strongly Confined Radiation

Abstract

The ability of metal nanoparticles to concentrate light via the plasmon resonance represents a unique opportunity for funneling the solar energy in photovoltaic devices. The absorption enhancement in plasmonic solar cells is predicted to be particularly prominent when the size of metal features falls below 20 nm, causing the strong confinement of radiation modes. Unfortunately, the ultrashort lifetime of such near-field radiation makes harvesting the plasmon energy in small-diameter nanoparticles a challenging task. Here, we develop plasmonic solar cells that harness the near-field emission of 5 nm Au nanoparticles by transferring the plasmon energy to band gap transitions of PbS semiconductor nanocrystals. The interfaces of Au and PbS domains were designed to support a rapid energy transfer at rates that outpace the thermal dephasing of plasmon modes. We demonstrate that central to the device operation is the inorganic passivation of Au nanoparticles with a wide gap semiconductor, which reduces carrier scattering and simultaneously improves the stability of heat-prone plasmonic films. The contribution of the Au near-field emission toward the charge carrier generation was manifested through the observation of an enhanced short circuit current and improved power conversion efficiency of mixed (Au, PbS) solar cells, as measured relative to PbS-only devices.

Colloidal Quantum Dot Solar Cells

“…The strong confinement of radiation modes provided by ultrasmall plasmonic nanoparticles has been demonstrated as well in a device that rapidly transfers hot electrons produced in 5 nm diameter gold particles to PbS CQDs. 209 This near-field energy transfer scheme resulted in a 41% increase in the short-circuit current and a 5% increase in the power conversion efficiency compared to those of a nonplasmonic device.…”

Advancing colloidal quantum dot photovoltaic technology

“…One study developed plasmonic solar cells which took advantage of the near-field effect in 5 nm Au nanoparticles [243]. Hot electron transfer directly from the excited plasmonic Au nanoparticles to the PbS CQD medium was optimized by the integration of a wide band gap semiconductor (CdS) to passivate the plasmonic nanoparticles.…”

Bimetallic Au-Ag Alloy Nanoparticles Improve Energy Harvesting of a TiO2/CdS Film

“…Plasmonic resonance energy transfer from Au NPs with sizes in the range of 5 to7 nm to PbS nanocrystals of 3.2 nm dimensions, caused band gap and impurity excitations in PbS. This energy transfer ensued in an approximately 41 % increase in short circuit current for the plasmonic cell in comparison to the cell devoid of the Au NPs . In another study, aggregates of Au@SiO 2 @TiO 2 NPs when used in a DSSC yielded an average PCE of 5.52 %, compared to a PCE of 2.81 %, when no NPs were used.…”