Measurement of defect densities and Urbach energies of tail states in PTB7 solar cells

Mehran Samiee; Pranav Joshi; Damir Aidarkhanov; Vikram Dalal

doi:10.1063/1.4896782

Measurement of defect densities and Urbach energies of tail states in PTB7 solar cells

Mehran Samiee, Pranav Joshi, Damir Aidarkhanov, Vikram Dalal

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

15 Citations (Scopus)

Abstract

Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is an important material for solar cells. We report on measurement of bulk and interfacial defects in PTB7 devices and measurement of Urbach energies of tail states near the HOMO and LUMO levels. The bulk defects and Urbach energies were measured using sub-gap quantum efficiency techniques and the donor/acceptor interfacial defects using capacitance techniques. Interfacial defects were found to peak at ∼0.7 eV above the HOMO level. Dark current-voltage curve indicated both interfacial and bulk recombination. Urbach energy for tail states near the HOMO level of PTB7 is 33 meV and near the LUMO level 55 meV.

Original language	English
Article number	133511
Journal	Applied Physics Letters
Volume	105
Issue number	13
DOIs	https://doi.org/10.1063/1.4896782
Publication status	Published - Sept 29 2014

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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title = "Measurement of defect densities and Urbach energies of tail states in PTB7 solar cells",

abstract = "Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is an important material for solar cells. We report on measurement of bulk and interfacial defects in PTB7 devices and measurement of Urbach energies of tail states near the HOMO and LUMO levels. The bulk defects and Urbach energies were measured using sub-gap quantum efficiency techniques and the donor/acceptor interfacial defects using capacitance techniques. Interfacial defects were found to peak at ∼0.7 eV above the HOMO level. Dark current-voltage curve indicated both interfacial and bulk recombination. Urbach energy for tail states near the HOMO level of PTB7 is 33 meV and near the LUMO level 55 meV.",

author = "Mehran Samiee and Pranav Joshi and Damir Aidarkhanov and Vikram Dalal",

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T1 - Measurement of defect densities and Urbach energies of tail states in PTB7 solar cells

AU - Samiee, Mehran

AU - Joshi, Pranav

AU - Aidarkhanov, Damir

AU - Dalal, Vikram

PY - 2014/9/29

Y1 - 2014/9/29

N2 - Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is an important material for solar cells. We report on measurement of bulk and interfacial defects in PTB7 devices and measurement of Urbach energies of tail states near the HOMO and LUMO levels. The bulk defects and Urbach energies were measured using sub-gap quantum efficiency techniques and the donor/acceptor interfacial defects using capacitance techniques. Interfacial defects were found to peak at ∼0.7 eV above the HOMO level. Dark current-voltage curve indicated both interfacial and bulk recombination. Urbach energy for tail states near the HOMO level of PTB7 is 33 meV and near the LUMO level 55 meV.

AB - Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is an important material for solar cells. We report on measurement of bulk and interfacial defects in PTB7 devices and measurement of Urbach energies of tail states near the HOMO and LUMO levels. The bulk defects and Urbach energies were measured using sub-gap quantum efficiency techniques and the donor/acceptor interfacial defects using capacitance techniques. Interfacial defects were found to peak at ∼0.7 eV above the HOMO level. Dark current-voltage curve indicated both interfacial and bulk recombination. Urbach energy for tail states near the HOMO level of PTB7 is 33 meV and near the LUMO level 55 meV.

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JO - Applied Physics Letters

JF - Applied Physics Letters

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M1 - 133511

ER -

Measurement of defect densities and Urbach energies of tail states in PTB7 solar cells

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