Frequency analysis on poly(3-hexylthiopene) rectifier using impedance spectroscopy

Kang, Chan‐mo; Kim, Seohee; Hong, Yongtaek; Lee, Changhee

doi:10.1016/j.tsf.2009.07.110

Cited by 25 publications

(20 citation statements)

References 18 publications

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“…This value is comparable to the values of 4.4 Â 10 -2 and 2 Â 10 -1 cm 2 V -1 s -1 reported for the trap-free mobility of holes in P3HT derived from FET 9 and TOF 18 experiments, respectively. In general, reported hole mobilities for P3HT ranges between 2 Â 10 -1 and 1 Â10 -4 cm 2 V -1 s -1 , whether measured by FET, 12,16,21,37 TOF, 10,18,23 SCLC,7 or pulse radiolysis TRMC. 8,9 The trap distribution parameter observed here is consistent with that observed in P3HT/PCBM devices; however, the hole mobilities here are higher due to observation at higher charge concentrations.…”

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confidence: 99%

“…For example, not only are high μ values required for the efficient collection of charge in polymer photovoltaics, but hole mobility limits the frequency response of organic transistors. 7 There are many approaches available to measure μ, each with inherent difficulties and limitations. For example, timeof-flight (TOF), field-effect transistors (FET) measurements, and space-charge-limited conduction (SCLC) are measured on devices and will thus include effects of processes that occur at the electrode interfaces.…”

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confidence: 99%

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Concentration-Dependent Hole Mobility and Recombination Coefficient in Bulk Heterojunctions Determined from Transient Absorption Spectroscopy

Eng

Barnes

Durrant

2010

J. Phys. Chem. Lett.

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A simple analytical function, based on the multiple trapping model, is used to describe the bimolecular recombination of charge carriers in a bulk heterojunction (BHJ) film in the presence of an exponential energetic tail of localized hole "trap" states. The function is used to fit charge carrier decay data from an unannealed P3HT/PCBM film measured by transient absorption. The analysis assumes that only free holes participate in recombination and transport. This implies an effective recombination rate coefficient which varies with the ratio of free to trapped holes. The fit parameters yield a bimolecular recombination constant for free holes with free electrons (k 0 = 3.4 Â 10 -12 cm 3 s -1 ) and information about the distribution of trap states (trap distribution parameter β = 0.29). Assuming the Langevin recombination limit, the analysis yields a concentrationdependent effective hole mobility saturating at μ 0 ≈ 7 Â 10 -2 cm 2 V -1 s -1 . This approach should be useful to compare BHJs in a consistent and meaningful manner.SECTION Electron Transport, Optical and Electronic Devices, Hard Matter E fficient photoinduced charge separation has been widely observed in organic film blends employing materials with different chemical potentials. There are extensive efforts to use such charge photogeneration for the photovoltaic conversion of solar energy. 1 The formation of a bulk heterojunction (BHJ), which is an interpenetrating network of different organic materials where the domain size of each phase is on the nanometre scale, facilitates efficient photoinduced charge separation. This is because the dissociation of photogenerated excitons into charge-carrying polarons (electrons and holes) generally occurs at the interface between the materials, and exciton diffusion lengths are typically only a few nanometers. 2 However, the enhanced charge dissociation achieved within a BHJ relative to that in a standard heterojunction comes at the cost of increased bimolecular recombination (recombination of electron and hole polaron charge carriers) due to the high interfacial area between the phases and the longer charge collection pathways in a photovoltaic device.Recently, it was shown that bimolecular recombination can severely limit the performance (particularly the opencircuit photovoltage, V oc ) of BHJ organic solar cells. 3 The work also indicated that the mobility of charge carriers was dependent on the concentration of separated charge in the device. 4 This is thought to be related to trapping of charge carriers in localized electronic states within the band gap of bulk organic materials. 5 Numerical simulations based on trapping/detrapping events using an exponential distribution of trap states have proven very successful in describing bimolecular recombination in BHJs, where recombination events are limited by the transport of charge carriers through a trap-rich medium. 6 To understand and optimize the function of devices based on organic materials, it is important to have a set of characterization tools enabling fu...

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confidence: 99%

mentioning

confidence: 99%

Concentration-Dependent Hole Mobility and Recombination Coefficient in Bulk Heterojunctions Determined from Transient Absorption Spectroscopy

Eng

Barnes

Durrant

2010

J. Phys. Chem. Lett.

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“…The hole mobilities can be measured precisely by fitting the dark JeV curves for single carrier devices to the SCLC model at low voltages. Here, the current is given by J ¼ 9ε 0 ε r mV 2 /8L 3 , where ε 0 ε r is the permittivity of the polymer, m is the carrier mobility, and L is the device thickness [18]. For the device without AN, the calculated hole mobility is 2.0 Â 10 À4 cm 2 /V s whereas the calculated hole mobility for the device with AN decreased by about a factor of two to 9.0 Â 10 À5 cm 2 /V s. The mobility results obtained from the SCLC analysis are exactly opposite the results obtained from the FET devices.…”

Section: Resultsmentioning

confidence: 99%

The effects of P3HT crystallinity in bilayer structure organic solar cells

Kim

Park

Nho

et al. 2014

Current Applied Physics

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“…R s demonstrated the contact resistance conceivably developed from the anode electrode (ITO), Since the value of L s is minimal (order of 10 − 18 ), the contribution of L s can be neglected, and the value of R s can be extracted at relatively high frequency (about 1 MHz) [66,67]. We can attribute the R 1 -C 1 and R 2 -C 2 components to the NRI bulk layer and NRI/Al junction, respectively [68]. Extracted values of the equivalent circuit elements are tabulated (Table 6).…”

Section: Equivalent Circuit Model Of Nri Devicementioning

confidence: 99%

“…Our group [20] extracted the mobility of iodine doped natural rubber using J-V analysis with the help of trap-free SCLC formula [21]. However, the mobility obtained using this method always smaller than the actual bulk mobility of the semiconductor [22]. Finally, electrochemical impedance spectroscopy (EIS) is found as the ideal tool to describe the charge carrier transport inside an organic layer sandwiched between anode and cathode electrodes, and it is valid for thin films also.…”

Section: Introductionmentioning

confidence: 99%

Charge transport properties of semiconducting natural rubber (Cis 1,4-polyisoprene)

Praveen

Mandin²,

Sauvage³

2020

Microelectronic Engineering

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For the first time, an effort has been made to evaluate the charge transport properties of semiconducting natural rubber. Four different ratios of iodine-rubber composites are synthesised and tested for charge transport by current density-voltage characteristics (J-V) and impedance spectroscopy. The optimal doping ratio for best mobility value is identified, and the effect of injection barrier height on mobility is discussed. An attempt has also been made to correlate the density of states (DOS) with mobility and doping ratio. The transport properties of semiconducting natural rubber are compared with one of the most popular p-type material, Poly(3-hexylthiophene-2,5-diyl) (P3HT) under the same ambience and experimental conditions to demonstrate its potential as a cost-effective and green alternative organic semiconductor.

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Frequency analysis on poly(3-hexylthiopene) rectifier using impedance spectroscopy

Cited by 25 publications

References 18 publications

Concentration-Dependent Hole Mobility and Recombination Coefficient in Bulk Heterojunctions Determined from Transient Absorption Spectroscopy

Concentration-Dependent Hole Mobility and Recombination Coefficient in Bulk Heterojunctions Determined from Transient Absorption Spectroscopy

The effects of P3HT crystallinity in bilayer structure organic solar cells

Charge transport properties of semiconducting natural rubber (Cis 1,4-polyisoprene)

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