A review of charge transport and recombination in polymer/fullerene organic solar cells

A. Pivrikas; N. S. Sariciftci; G. Juška; R. Österbacka

doi:10.1002/pip.791

A review of charge transport and recombination in polymer/fullerene organic solar cells

A. Pivrikas^*, N. S. Sariciftci, G. Juška, R. Österbacka

^*Corresponding author for this work

Physics

Research output: Contribution to journal › Article › Scientific › peer-review

543 Citations (Scopus)

Abstract

The charge carrier transport and recombination in two types of thermally treated bulk-heterojunction solar cells is reviewed: in regioregularpoly(3- hexylthiophene) (RRP3HT) mixed with 1-(3-methoxycarbonyl)propyll-phenyl-[6,6]- methanofullerene (PCBM) and in the blend of poly[2-methoxy-5-(3,7- dimethyloctyloxy)phenylene vinylene] (MDMO-PPV) mixed with PCBM. The charge carrier mobility and bimolecular recombination coefficient have been comparatively studied by using various techniques including Time-ofFlight (ToF), Charge Extraction by Linearly Increasing Voltage (CELTV), Double Injection (DI) transients, Current-Voltage (I- V) technique. It was found that the carrier mobility is at least an order of magnitude higher in RRP3HT/PCBM blends compared to MDMO-PPV/PCBM. Moreover, all used techniques demonstrate a heavily reduced charge carrier recombination in RRP3HT/PCBM films compared to Langevin-type carrier bimolecular recombination in MDMO-PPV/PCBM blends. As a result of long carrier lifetimes the formation of high carrier concentration plasma in RRP3HT/PCBM blends is demonstrated and plasma extraction methods were used to directly estimate the charge carrier mobility and bimolecular recombination coefficients simultaneously. A weak dependence of bimolecular recombination coefficient on the applied electric field and temperature demonstrates that carrier recombination is not dominated by charge carrier mobility (Langevin-type recombination) in RRP3HT/PCBM blends. Furthermore, we found from CELTV techniques that electron mobility in RRP3HT/PCBM blends is independent on relaxation time in the experimental time window (approx. hundreds of microseconds to tens of milliseconds). This reduced carrier bimolecular recombination in RRP3HT/PCBM blends implies that the much longer carrier lifetimes can be reached at the same concentrations which finally results in higher photocurrent and larger power conversion efficiency of RRP3HT/PCBM solar cells.

Original language	English
Pages (from-to)	677-696
Number of pages	20
Journal	Progress in Photovoltaics: Research and Applications
Volume	15
Issue number	8
DOIs	https://doi.org/10.1002/pip.791
Publication status	Published - Dec 2007
MoE publication type	A1 Journal article-refereed

Keywords

Bimolecular recombination
Bulk-heterojunction
Charge transport
Langevin recombination
Solar cells
Time-of-flight

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10.1002/pip.791

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title = "A review of charge transport and recombination in polymer/fullerene organic solar cells",

abstract = "The charge carrier transport and recombination in two types of thermally treated bulk-heterojunction solar cells is reviewed: in regioregularpoly(3- hexylthiophene) (RRP3HT) mixed with 1-(3-methoxycarbonyl)propyll-phenyl-[6,6]- methanofullerene (PCBM) and in the blend of poly[2-methoxy-5-(3,7- dimethyloctyloxy)phenylene vinylene] (MDMO-PPV) mixed with PCBM. The charge carrier mobility and bimolecular recombination coefficient have been comparatively studied by using various techniques including Time-ofFlight (ToF), Charge Extraction by Linearly Increasing Voltage (CELTV), Double Injection (DI) transients, Current-Voltage (I- V) technique. It was found that the carrier mobility is at least an order of magnitude higher in RRP3HT/PCBM blends compared to MDMO-PPV/PCBM. Moreover, all used techniques demonstrate a heavily reduced charge carrier recombination in RRP3HT/PCBM films compared to Langevin-type carrier bimolecular recombination in MDMO-PPV/PCBM blends. As a result of long carrier lifetimes the formation of high carrier concentration plasma in RRP3HT/PCBM blends is demonstrated and plasma extraction methods were used to directly estimate the charge carrier mobility and bimolecular recombination coefficients simultaneously. A weak dependence of bimolecular recombination coefficient on the applied electric field and temperature demonstrates that carrier recombination is not dominated by charge carrier mobility (Langevin-type recombination) in RRP3HT/PCBM blends. Furthermore, we found from CELTV techniques that electron mobility in RRP3HT/PCBM blends is independent on relaxation time in the experimental time window (approx. hundreds of microseconds to tens of milliseconds). This reduced carrier bimolecular recombination in RRP3HT/PCBM blends implies that the much longer carrier lifetimes can be reached at the same concentrations which finally results in higher photocurrent and larger power conversion efficiency of RRP3HT/PCBM solar cells.",

keywords = "Bimolecular recombination, Bulk-heterojunction, Charge transport, Langevin recombination, Solar cells, Time-of-flight",

author = "A. Pivrikas and Sariciftci, {N. S.} and G. Ju{\v s}ka and R. {\"O}sterbacka",

year = "2007",

month = dec,

doi = "10.1002/pip.791",

language = "English",

volume = "15",

pages = "677--696",

journal = "Progress in Photovoltaics: Research and Applications",

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T1 - A review of charge transport and recombination in polymer/fullerene organic solar cells

AU - Pivrikas, A.

AU - Sariciftci, N. S.

AU - Juška, G.

AU - Österbacka, R.

PY - 2007/12

Y1 - 2007/12

N2 - The charge carrier transport and recombination in two types of thermally treated bulk-heterojunction solar cells is reviewed: in regioregularpoly(3- hexylthiophene) (RRP3HT) mixed with 1-(3-methoxycarbonyl)propyll-phenyl-[6,6]- methanofullerene (PCBM) and in the blend of poly[2-methoxy-5-(3,7- dimethyloctyloxy)phenylene vinylene] (MDMO-PPV) mixed with PCBM. The charge carrier mobility and bimolecular recombination coefficient have been comparatively studied by using various techniques including Time-ofFlight (ToF), Charge Extraction by Linearly Increasing Voltage (CELTV), Double Injection (DI) transients, Current-Voltage (I- V) technique. It was found that the carrier mobility is at least an order of magnitude higher in RRP3HT/PCBM blends compared to MDMO-PPV/PCBM. Moreover, all used techniques demonstrate a heavily reduced charge carrier recombination in RRP3HT/PCBM films compared to Langevin-type carrier bimolecular recombination in MDMO-PPV/PCBM blends. As a result of long carrier lifetimes the formation of high carrier concentration plasma in RRP3HT/PCBM blends is demonstrated and plasma extraction methods were used to directly estimate the charge carrier mobility and bimolecular recombination coefficients simultaneously. A weak dependence of bimolecular recombination coefficient on the applied electric field and temperature demonstrates that carrier recombination is not dominated by charge carrier mobility (Langevin-type recombination) in RRP3HT/PCBM blends. Furthermore, we found from CELTV techniques that electron mobility in RRP3HT/PCBM blends is independent on relaxation time in the experimental time window (approx. hundreds of microseconds to tens of milliseconds). This reduced carrier bimolecular recombination in RRP3HT/PCBM blends implies that the much longer carrier lifetimes can be reached at the same concentrations which finally results in higher photocurrent and larger power conversion efficiency of RRP3HT/PCBM solar cells.

AB - The charge carrier transport and recombination in two types of thermally treated bulk-heterojunction solar cells is reviewed: in regioregularpoly(3- hexylthiophene) (RRP3HT) mixed with 1-(3-methoxycarbonyl)propyll-phenyl-[6,6]- methanofullerene (PCBM) and in the blend of poly[2-methoxy-5-(3,7- dimethyloctyloxy)phenylene vinylene] (MDMO-PPV) mixed with PCBM. The charge carrier mobility and bimolecular recombination coefficient have been comparatively studied by using various techniques including Time-ofFlight (ToF), Charge Extraction by Linearly Increasing Voltage (CELTV), Double Injection (DI) transients, Current-Voltage (I- V) technique. It was found that the carrier mobility is at least an order of magnitude higher in RRP3HT/PCBM blends compared to MDMO-PPV/PCBM. Moreover, all used techniques demonstrate a heavily reduced charge carrier recombination in RRP3HT/PCBM films compared to Langevin-type carrier bimolecular recombination in MDMO-PPV/PCBM blends. As a result of long carrier lifetimes the formation of high carrier concentration plasma in RRP3HT/PCBM blends is demonstrated and plasma extraction methods were used to directly estimate the charge carrier mobility and bimolecular recombination coefficients simultaneously. A weak dependence of bimolecular recombination coefficient on the applied electric field and temperature demonstrates that carrier recombination is not dominated by charge carrier mobility (Langevin-type recombination) in RRP3HT/PCBM blends. Furthermore, we found from CELTV techniques that electron mobility in RRP3HT/PCBM blends is independent on relaxation time in the experimental time window (approx. hundreds of microseconds to tens of milliseconds). This reduced carrier bimolecular recombination in RRP3HT/PCBM blends implies that the much longer carrier lifetimes can be reached at the same concentrations which finally results in higher photocurrent and larger power conversion efficiency of RRP3HT/PCBM solar cells.

KW - Bimolecular recombination

KW - Bulk-heterojunction

KW - Charge transport

KW - Langevin recombination

KW - Solar cells

KW - Time-of-flight

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JO - Progress in Photovoltaics: Research and Applications

JF - Progress in Photovoltaics: Research and Applications

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ER -

A review of charge transport and recombination in polymer/fullerene organic solar cells

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Keywords

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