The Mobility and Decay Kinetics of Charge Carriers in Pulse-Ionized Microcrystalline PCBM Powder

Haas, Matthijs P. de; Warman, John M.; Anthopoulos, Thomas D.; Leeuw, Dago M. de

doi:10.1002/adfm.200500882

Cited by 68 publications

(93 citation statements)

References 38 publications

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“…31 Assuming that ∑µ in 2:PCBM is dominated by carriers in the crystalline PCBM domains, and taking the value for their mobility to be in the range 0.04-0.07 cm 2 /(V s), 30 the data from Figure 5 allow us to estimate the yield for free-carrier generation per photon absorbed, φ, to be in the range 0.28-0.49 and possibly even lower when the highest range of the ∑µ in PCBM crystallites (up to 0.3 cm 2 / (V s)) 26 is considered. By contrast, the yield in poly(3-hexylthiophene) with just 1% PCBM is 0.75 and increases in blends with higher PCBM content.…”

Section: Resultsmentioning

confidence: 99%

“…30 A value of >0.04 cm 2 /(V s) has also been measured for the ∑µ of PCBM powders using pulse radiolysis. 26 For Figure 5. The φ∑µ product for both neat dendrimers and dendrimer:PCBM blends as a function of photon flux.…”

Section: Resultsmentioning

confidence: 99%

“…The crystalline PCBM phase that is only present in 2:PCBM blends increases ∆G due to the high electron mobility in this phase, as has been reported previously. 26 The photoconductivity signal from 1:PCBM includes contributions from both holes in 1 and electrons in PCBM, but poor phase separation present in this blend most likely reduces the electron mobility in the PCBM. When comparing the normalized photoconductivity decays of the blends (Figure 4d), the carrier lifetime is unchanged in 1:PCBM compared to the neat film of 1, while the carriers are longer lived in 2:PCBM.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Conjugated Thiophene Dendrimer with an Electron-Withdrawing Core and Electron-Rich Dendrons: How the Molecular Structure Affects the Morphology and Performance of Dendrimer:Fullerene Photovoltaic Devices

et al. 2010

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The combination of electron-rich and electron-poor moieties in conjugated molecules is frequently utilized in order to red shift the absorption spectrum and improve photon harvesting in bulk heterojunction photovoltaic devices. In this study we characterize a conjugated thiophene dendrimer that has an electron-withdrawing core and electron-rich dendrons in order to investigate the effects of this design approach on the salient properties that influence the performance of photovoltaic devices with this dendrimer donor. Beside the absorption onset, these properties are the morphology of dendrimer:fullerene films and the dynamics of photoinduced carrier generation and loss. For comparison we also characterize a control dendrimer with the same structure but without the electron-withdrawing core. In addition to lowering the band gap by ca. 0.5 eV, the electron-withdrawing core also planarizes the dendrimer resulting in enhanced order in bulk heterojunction films. We observe longer photocarrier lifetimes in this ordered structure compared to the films of the predominantly amorphous control. The characterization of dendrimer:fullerene bulk heterojunction photovoltaic devices shows no voltage loss despite the decreased absorption onset. The properties of the device are consistent with the improved photocarrier lifetimes, but they are limited by a low short-circuit photocurrent density. We attribute this to electron confinement in the core that hinders transfer to the fullerene acceptor.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Conjugated Thiophene Dendrimer with an Electron-Withdrawing Core and Electron-Rich Dendrons: How the Molecular Structure Affects the Morphology and Performance of Dendrimer:Fullerene Photovoltaic Devices

et al. 2010

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“…[10][11][12][13]. The study of PC 61 BM microcrystalline powder by pulse-radiolysis time-resolved microwave conductivity provides the sum of electron and hole mobility in the range of 4 Á 10 À2 -3 Á 10 À1 cm 2 /(V s) [14]. This may be considered as being approximately equal to the half of the electron mobility, since the hole mobility in PC 61 BM is by orders of magnitude lower.…”

Section: Introductionmentioning

confidence: 99%

Time-independent, high electron mobility in thin PC 61 BM films: Relevance to organic photovoltaics

Devižis

Hertel

Meerholz

et al. 2014

Organic Electronics

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a b s t r a c tUltrafast optical probing of electric field by means of electroabsorption combined with conventional photocurrent measurements was employed to investigate the drift and mobility dynamics of photo-generated charge carriers in the pristine PC 61 BM film and in the blend with a merocyanine dye. Electrons passed a 40 nm thick PC 61 BM film within a few picoseconds with time-independent and weakly dispersive mobility. The electron mobility is 1 cm 2 /(V s) at 1 MV/cm and an estimate of the zero-field mobility yields 5 Á 10 À2 cm 2 /(V s). The initial electron mobility in the blend is of the order of 10 À2 cm 2 / (V s) and decreases rapidly. We conclude that electron motion in PC 61 BM based organic bulk hetero-junction solar cells is limited by barriers between PC 61 BM domains rather than by intrinsic PC 61 BM properties.

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“…The kinetics of charge carriers in PCBM monitored from the nanosecond to the millisecond regime in the absence of electric field have been the object of study in a recent publication. 26 In this work the population of charge carriers were generated with 2 ns ionizing high energy pulses and probe by monitoring changes in the microwave conductivity. It turned out that the kinetics followed stretched exponential law with a long decay component extending to the millisecond regime.…”

Section: Discussionmentioning

confidence: 99%

Subpicosecond photoinduced Stark spectroscopy in fullerene-based devices

et al. 2007

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We present a detailed study of the charge photogeneration and decay kinetics in ͓6,6͔-phenyl C61-butyric acid methyl ester by performing subpicosecond Stark spectroscopy measurements. Owing to the large photogenerated charge density and the strength of the applied field, progressive quenching of the Stark signal is observed during the first 20 ps, followed by a slow recovery at longer time scales. The quenching regime provides information on the average e-h separation and drift motion within the e-h pair whereas the recovery is related to the kinetics of charges and their recombination probability.

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The Mobility and Decay Kinetics of Charge Carriers in Pulse-Ionized Microcrystalline PCBM Powder

Cited by 68 publications

References 38 publications

Conjugated Thiophene Dendrimer with an Electron-Withdrawing Core and Electron-Rich Dendrons: How the Molecular Structure Affects the Morphology and Performance of Dendrimer:Fullerene Photovoltaic Devices

Conjugated Thiophene Dendrimer with an Electron-Withdrawing Core and Electron-Rich Dendrons: How the Molecular Structure Affects the Morphology and Performance of Dendrimer:Fullerene Photovoltaic Devices

Time-independent, high electron mobility in thin PC 61 BM films: Relevance to organic photovoltaics

Subpicosecond photoinduced Stark spectroscopy in fullerene-based devices

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