Polychiral Semiconducting Carbon Nanotube–Fullerene Solar Cells

Gong, Maogang; Shastry, Tejas A.; Xie, Yu; Bernardi, Marco; Jasion, Daniel; Luck, Kyle A.; Marks, Tobin J.; Grossman, Jeffrey C.; Ren, Shenqiang; Hersam, Mark C.

doi:10.1021/nl5027452

Cited by 111 publications

(191 citation statements)

References 38 publications

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“…5,14,15 The low values found for L D , in both SWCNT and C 60 thin films, suggest that SWCNT/ fullerene device efficiencies will likely benefit from bulk heterojunction geometries, as demonstrated in recent studies. 9,10 However, the low fill factor of these initial demonstrations of bulk heterojunctions 9,10 suggests that the source of significant recombination losses should be explored and mitigated. 22 In this study, we utilized femtosecond transient absorption spectroscopy and kinetic modeling to determine a singlet exciton diffusion length of approximately 5 nm in thin films of C 60 .…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions

Dowgiallo

Mistry

Johnson

et al. 2016

J. Phys. Chem. Lett.

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The efficiency of thin-film organic photovoltaic (OPV) devices relies heavily upon the transport of excitons to type-II heterojunction interfaces, where there is sufficient driving force for exciton dissociation and ultimately the formation of charge carriers. Semiconducting single-walled carbon nanotubes (SWCNTs) are strong near-infrared absorbers that form type-II heterojunctions with fullerenes such as C60. Although the efficiencies of SWCNT-fullerene OPV devices have climbed over the past few years, questions remain regarding the fundamental factors that currently limit their performance. In this study, we determine the exciton diffusion length in the C60 layer of SWCNT-C60 bilayer active layers using femtosecond transient absorption measurements. We demonstrate that hole transfer from photoexcited C60 molecules to SWCNTs can be tracked by the growth of narrow spectroscopic signatures of holes in the SWCNT "reporter layer". In bilayers with thick C60 layers, the SWCNT charge-related signatures display a slow rise over hundreds of picoseconds, reflecting exciton diffusion through the C60 layer to the interface. A model based on exciton diffusion with a Beer-Lambert excitation profile, as well as Monte Carlo simulations, gives the best fit to the data as a function of C60 layer thickness using an exciton diffusion length of approximately 5 nm.

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Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions

Dowgiallo

Mistry

Johnson

et al. 2016

J. Phys. Chem. Lett.

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“…26 Their utility has already been demonstrated as high conductivity channels for field effect transistors, 27-28 photoabsorbers in solar cells, [29][30][31][32] and NIR light emitters. [33][34] For all of these applications, semiconducting carbon nanotubes are required, which must be purified from their metallic counterparts.…”

Section: Introductionmentioning

confidence: 99%

Polarization-Controlled Two-Dimensional White-Light Spectroscopy of Semiconducting Carbon Nanotube Thin Films

et al. 2016

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Polarized two-dimensional white-light (2D-WL) spectra are reported for thin films of semiconducting carbon nanotubes. The orientational responses for 4-point correlation functions are derived for samples that are isotropic in two dimensions. Spectra measured using <-45°,+45°,0°,90°> polarizations eliminate the diagonal peaks in the spectra arising from S1 transitions to uncover cross peaks to a weaker transition that is assigned to radial breathing modes. In nanotubes purified by unwrapping PFO-BPY polymer using metal chelation, an absorption at 1160 nm is observed that is assigned to hole doping that forms trions. The trion peak may have a transition dipole non-parallel to the S1 transitions, and so its cross peak is prominent in polarized 2D WL spectra. Energy transfer of photoexcitons to the trion peak occurs within 1 ps. Identifying and understanding the effects of purification on the electronic structure of thin films of semiconducting carbon nanotubes is important for learning how the inherent photophysics of individual carbon nanotubes translates to coupled nanotube thin film materials.

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“…During the last decade or so, the potential benefits of using carbon nanotubes in solar cells has been explored from both a fundamental theory point of view [1–2], as well as experimentally in a host of different device architectures, including as additives in dye solar cells [3–4], organic photovoltaics [5–6], and perovskites [7–8] and as the active light absorbing component in conjunction with acceptors such as fullerenes [9–12]. Carbon nanotube–silicon heterojunctions can also function as solar cells [13–14] and over the last few years of development the power conversion efficiency (PCE) of these devices has been steadily increasing [15–22], with the most recent high efficiency record by Wang et al now standing at ≈17% [23].…”

Section: Introductionmentioning

confidence: 99%

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

Stolz¹,

Tune

Flavel³

2016

Beilstein J. Nanotechnol.

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SummaryRecent results in the field of carbon nanotube–silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning – in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube–silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared.

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Polychiral Semiconducting Carbon Nanotube–Fullerene Solar Cells

Cited by 111 publications

References 38 publications

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions

Polarization-Controlled Two-Dimensional White-Light Spectroscopy of Semiconducting Carbon Nanotube Thin Films

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

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Polychiral Semiconducting Carbon Nanotube–Fullerene Solar Cells

Cited by 111 publications

References 38 publications

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C60 Heterojunctions

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C60 Heterojunctions

Polarization-Controlled Two-Dimensional White-Light Spectroscopy of Semiconducting Carbon Nanotube Thin Films

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

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Product

Resources

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Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions

Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube–C₆₀ Heterojunctions