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Photoluminescence-Downshifting in Nanowire Solar Cells, an Exploration for third Generation Photovoltaics

Näsström, Hampus LU (2018) PHYM01 20181
Department of Physics
Chemical Physics
Abstract
The use of InP nanowires solar cells as a platform for the third generation concept of spectral conversion has been explored by embedding the Coumarin 120 dye between the nanowires of the solar cells. The InP solar cells have been characterised by measuring the external quantum efficiency, EQE, and the current voltage, JV, curve. For the EQE measurement an imaging system was constructed to constrain the light within the 800×800 μm active areas. Through numerical finite element method, FEM, simulations the decrease in EQE for incoming wavelengths below 400 nm was attributed to parasitic absorption in the Indium tin oxide, ITO, conducting layer. To avoid the parasitic absorption in the ITO layer, a blend of Coumarin 120, C120, dye in... (More)
The use of InP nanowires solar cells as a platform for the third generation concept of spectral conversion has been explored by embedding the Coumarin 120 dye between the nanowires of the solar cells. The InP solar cells have been characterised by measuring the external quantum efficiency, EQE, and the current voltage, JV, curve. For the EQE measurement an imaging system was constructed to constrain the light within the 800×800 μm active areas. Through numerical finite element method, FEM, simulations the decrease in EQE for incoming wavelengths below 400 nm was attributed to parasitic absorption in the Indium tin oxide, ITO, conducting layer. To avoid the parasitic absorption in the ITO layer, a blend of Coumarin 120, C120, dye in poly(methyl methacrylate), PMMA, was deposited between the nanowires with the goal of shifting incoming UV photons to longer wavelengths through the Stokes shift of the dye. The application method was optimised for thin films and a mixture of acetone and chlorobenzene, CBZ, was found to be the optimal solvent for drop casting thick homogeneous films. Finally, the coated cells were shown to have a 10 % lower short circuit current than the uncoated ones due to lower EQE throughout the full spectral range which was attributed to reflection caused by the PMMA. The lack of response from the C120 dye appeared due to the low fluorescence quantum yield of the dye in PMMA. Therefore, high quantum yield was established as a key prerequisite for spectral conversion. (Less)
Please use this url to cite or link to this publication:
author
Näsström, Hampus LU
supervisor
organization
course
PHYM01 20181
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Solar cells, Nanowires, Third generation concepts, Spectral conversion
language
English
id
8952351
date added to LUP
2018-06-25 14:10:54
date last changed
2018-06-25 14:10:54
@misc{8952351,
  abstract     = {{The use of InP nanowires solar cells as a platform for the third generation concept of spectral conversion has been explored by embedding the Coumarin 120 dye between the nanowires of the solar cells. The InP solar cells have been characterised by measuring the external quantum efficiency, EQE, and the current voltage, JV, curve. For the EQE measurement an imaging system was constructed to constrain the light within the 800×800 μm active areas. Through numerical finite element method, FEM, simulations the decrease in EQE for incoming wavelengths below 400 nm was attributed to parasitic absorption in the Indium tin oxide, ITO, conducting layer. To avoid the parasitic absorption in the ITO layer, a blend of Coumarin 120, C120, dye in poly(methyl methacrylate), PMMA, was deposited between the nanowires with the goal of shifting incoming UV photons to longer wavelengths through the Stokes shift of the dye. The application method was optimised for thin films and a mixture of acetone and chlorobenzene, CBZ, was found to be the optimal solvent for drop casting thick homogeneous films. Finally, the coated cells were shown to have a 10 % lower short circuit current than the uncoated ones due to lower EQE throughout the full spectral range which was attributed to reflection caused by the PMMA. The lack of response from the C120 dye appeared due to the low fluorescence quantum yield of the dye in PMMA. Therefore, high quantum yield was established as a key prerequisite for spectral conversion.}},
  author       = {{Näsström, Hampus}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Photoluminescence-Downshifting in Nanowire Solar Cells, an Exploration for third Generation Photovoltaics}},
  year         = {{2018}},
}