Abstract

The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell.

Original languageEnglish
Pages (from-to)6139-6146
Number of pages8
JournalACS Nano
Volume10
Issue number6
DOIs
Publication statusPublished - 28 Jun 2016

Fingerprint

Electric space charge
Oxides
space charge
Solar cells
Charge carriers
solar cells
Surface potential
oxides
charge carriers
Carrier transport
Lighting
illumination
Photovoltaic effects
Wavelength
photovoltaic effect
Nanorods
Topography
cross sections
Charge transfer
profiles

Keywords

  • charge carrier
  • interface
  • Kelvin probe force microscopy
  • surface potential
  • ZnO nanorods/CuO

Cite this

@article{f9b27a93349149ecb47e14c662eec7a2,
title = "Observation of Space Charge Dynamics Inside an All Oxide Based Solar Cell",
abstract = "The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell.",
keywords = "charge carrier, interface, Kelvin probe force microscopy, surface potential, ZnO nanorods/CuO",
author = "Shrabani Panigrahi and Tomas Calmeiro and Martins, {Rodrigo Ferr{\~a}o de Paiva} and D. Nunes and Fortunato, {Elvira Maria Correia}",
note = "This study was funded by the European Commission under the FP7 All Oxide PV project {"}Novel Composite Oxides by Combinatorial Material Synthesis for Next Generation All-Oxide-Photovoltaics{"} number 309018 and the FP7 ERC AdG project {"}Transparent Electro-nics{"} number 228144. This work was partially supported by FEDER funds through the COMPETE 2020 Programme and National Funds throught FCT - Portuguese Foundation for Science and Technology under the Project No. UID/CTM/50025/2013. We are thankful to A. Lopes for the help to polish the device for KPFM measurements. FP7 ERC AdG project {"}Transparent Electro-nics{"} (228144)",
year = "2016",
month = "6",
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doi = "10.1021/acsnano.6b02090",
language = "English",
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issn = "1936-0851",
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TY - JOUR

T1 - Observation of Space Charge Dynamics Inside an All Oxide Based Solar Cell

AU - Panigrahi, Shrabani

AU - Calmeiro, Tomas

AU - Martins, Rodrigo Ferrão de Paiva

AU - Nunes, D.

AU - Fortunato, Elvira Maria Correia

N1 - This study was funded by the European Commission under the FP7 All Oxide PV project "Novel Composite Oxides by Combinatorial Material Synthesis for Next Generation All-Oxide-Photovoltaics" number 309018 and the FP7 ERC AdG project "Transparent Electro-nics" number 228144. This work was partially supported by FEDER funds through the COMPETE 2020 Programme and National Funds throught FCT - Portuguese Foundation for Science and Technology under the Project No. UID/CTM/50025/2013. We are thankful to A. Lopes for the help to polish the device for KPFM measurements. FP7 ERC AdG project "Transparent Electro-nics" (228144)

PY - 2016/6/28

Y1 - 2016/6/28

N2 - The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell.

AB - The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell.

KW - charge carrier

KW - interface

KW - Kelvin probe force microscopy

KW - surface potential

KW - ZnO nanorods/CuO

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U2 - 10.1021/acsnano.6b02090

DO - 10.1021/acsnano.6b02090

M3 - Article

VL - 10

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EP - 6146

JO - ACS Nano

JF - ACS Nano

SN - 1936-0851

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