Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

Syed Mubeen; Gerardo HERNANDEZ-SOSA; Daniel Moses; Joun Lee; Martin Moskovits

doi:10.1021/nl203457v

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Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

Journal article

Peer reviewed

Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

Syed Mubeen, Gerardo HERNANDEZ-SOSA, Daniel Moses, Joun Lee and Martin Moskovits

Nano letters, Vol.11(12), pp.5548-5552

2011

DOI: 10.1021/nl203457v

PMID: 22040462

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Abstract

A fruitful paradigm in the development of low-cost and efficient photovoltaics is to dope or otherwise photosensitize wide band gap semiconductors in order to improve their light harvesting ability for light with sub-band-gap photon energies.1–8 Here, we report significant photosensitization of TiO2 due to the direct injection by quantum tunneling of hot electrons produced in the decay of localized surface-plasmon polaritons excited in gold nanoparticles (AuNPs) embedded in the semiconductor (TiO2). Surface plasmon decay produces electron–hole pairs in the gold.9–15 We propose that a significant fraction of these electrons tunnel into the semiconductor’s conduction band resulting in a significant electron current in the TiO2 even when the device is illuminated with light with photon energies well below the semiconductor’s band gap. Devices fabricated with (nonpercolating) multilayers of AuNPs in a TiO2 film produced over 1000-fold increase in photoconductance when illuminated at 600 nm over what TiO2 films devoid of AuNPs produced. The overall current resulting from illumination with visible light is ∼50% of the device current measured with UV (ℏω > Eg band gap) illumination. The above observations suggest that plasmonic nanostructures (which can be fabricated with absorption properties that cover the full solar spectrum) can function as a viable alternative to organic photosensitizers for photovoltaic and photodetection applications.

Applied Sciences

Materials Science

Physics

Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Condensed matter: electronic structure, electrical, magnetic, and optical properties

Cross-disciplinary physics: materials science; rheology

Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems

Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures

Electronics

Exact sciences and technology

Molecular electronics, nanoelectronics

Nanocrystalline materials

Nanoscale materials and structures: fabrication and characterization

Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices

Surface and interface electron states

Details

Title: Subtitle: Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers
Creators: Syed Mubeen - University of California, Santa Barbara
Gerardo HERNANDEZ-SOSA - University of California, Santa Barbara
Daniel Moses - University of California, Santa Barbara
Joun Lee - University of California, Santa Barbara
Martin Moskovits - University of California, Santa Barbara
Resource Type: Journal article
Publication Details: Nano letters, Vol.11(12), pp.5548-5552
Publisher: American Chemical Society
DOI: 10.1021/nl203457v
PMID: 22040462
ISSN: 1530-6984
eISSN: 1530-6992
Language: English
Date published: 2011
Academic Unit: Civil and Environmental Engineering; Chemical and Biochemical Engineering
Record Identifier: 9984197167102771

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