Multiple exciton generation induced enhancement of the photoresponse of pulsed-laser-ablation synthesized single-wall-carbon-nanotube/PbS-quantum-dots nanohybrids
| Autor: | Ibrahima Ka, Vincent Le Borgne, Morinobu Endo, Dongling Ma, My Ali El Khakani, Kazunori Fujisawa, Yoong Ahm Kim, Takuya Hayashi |
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| Rok vydání: | 2016 |
| Předmět: |
Photocurrent
Multidisciplinary Materials science Laser ablation business.industry Photoconductivity 02 engineering and technology Carbon nanotube 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Article 0104 chemical sciences law.invention Pulsed laser deposition Multiple exciton generation Quantum dot law Optoelectronics Quantum efficiency 0210 nano-technology business |
| Zdroj: | Scientific Reports |
| ISSN: | 2045-2322 |
| DOI: | 10.1038/srep20083 |
| Popis: | The pulsed laser deposition method was used to decorate appropriately single wall carbon nanotubes (SWCNTs) with PbS quantum dots (QDs), leading to the formation of a novel class of SWCNTs/PbS-QDs nanohybrids (NHs), without resorting to any ligand engineering and/or surface functionalization. The number of laser ablation pulses (NLp) was used to control the average size of the PbS-QDs and their coverage on the SWCNTs’ surface. Photoconductive (PC) devices fabricated from these SWCNTs/PbS-QDs NHs have shown a significantly enhanced photoresponse, which is found to be PbS-QD size dependent. Wavelength-resolved photocurrent measurements revealed a strong photoconductivity of the NHs in the UV-visible region, which is shown to be due to multiple exciton generation (MEG) in the PbS-QDs. For the 6.5 nm-diameter PbS-QDs (with a bandgap (Eg) = 0.86 eV), the MEG contribution of the NHs based PC devices was shown to lead to a normalized internal quantum efficiency in excess of 300% for photon energies ≥4.5Eg. While the lowest MEG threshold in our NHs based PC devices is found to be of ~2.5Eg, the MEG efficiency reaches values as high as 0.9 ± 0.1. |
| Databáze: | OpenAIRE |
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