The effect of PbS quantum dots on molecular dynamics and conductivity of PTB7:PC71BM bulk heterojunction as revealed by dielectric spectroscopy

Asăndulesa, Mihai; Kostromin, Sergei; Aleksandrov, A. E.; Тамеев, А. Р.; Bronnikov, Sergei

doi:10.1039/d2cp00770c

Cited by 5 publications

(6 citation statements)

References 53 publications

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“…Previous reports stated that a linear decrease of ε" towards higher frequencies with a slope close to -1 in the log-log presentation is a clear response for the presence of free charge carriers in the bulk material. 14,15 This regime correlates well with that of space charge polarization observed in the ε'(f) profiles. On the other hand, in the high frequency region, the dipolar signal is slightly deviated from the straight line, typically for the relaxation processes of the material.…”

Section: Resultssupporting

confidence: 80%

“…This regime is characteristic for σdc component and may be assigned to the transport of free charge carriers through the material in the presence of an external electrical field. 14 At higher frequencies, the conductivity increases progressively with frequency increase, as a typical behavior for the σac regime. The latter is attributed to the dipolar relaxation processes of the material.…”

Section: Resultsmentioning

confidence: 90%

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Electrical properties of poly(3,4-ethylenedioxythiophene) threaded by cucurbit[7]uril

Asăndulesa¹,

Resmeriță²,

Farcas³

2023

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies XI

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Supramolecular PEDOT∙CB7-PS polypseudorotaxane and PEDOT∙CB7-PR polyrotaxane were prepared by threading the cucurbit[7]uril (CB7) molecules over the 3,4-ethylenedioxythiophene (EDOT) monomer, followed by oxidative polymerization . The dielectric parameters of these encapsulated compounds were investigated by means of broadband dielectric spectroscopy. The evolution of dielectric constant with frequency clearly emphasizes two distinct regimes, assigned with the space charge polarization (at low frequencies) and the ‘intrinsic’ dipolar activity (at high frequencies). The spectra of dielectric loss vs. frequency reveal a dominant signal for conductivity of free charge carriers. Furthermore, frequency dependences of conductivity profiles are strongly correlated with the dielectric constant and dielectric loss components and disclose the clear signal of electrical conductivity. The conductivity of PEDOT∙CB7-PR was found to be with one order of magnitude higher than that of the pristine PEDOT.

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Section: Resultssupporting

confidence: 80%

Section: Resultsmentioning

confidence: 90%

Electrical properties of poly(3,4-ethylenedioxythiophene) threaded by cucurbit[7]uril

Asăndulesa¹,

Resmeriță²,

Farcas³

2023

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies XI

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“…Moreover, at temperatures higher than 0 °C, ε′ shows a pronounced decrease, especially at low frequencies. According to the literature, this behavior of ε′ is produced by the accumulation of charge carriers at the interface between the sample surfaces and the electrodes used to perform the dielectric measurements [ 46 , 47 ]. Undoubtedly, the electrode polarization process of the blocked charges affects the dipolar-type signal.…”

Section: Resultsmentioning

confidence: 99%

Multi-Functional Materials Based on Cu-Doped TiO2 Ceramic Fibers with Enhanced Pseudocapacitive Performances and Their Dielectric Characteristics

Pascariu¹,

Homocianu²,

Vacareanu³

et al. 2022

Polymers

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In this work, pure TiO2 and Cu (0.5, 1, 2%)-doped TiO2 composites prepared by electrospinning technique followed by calcination at 900 °C, and having high pseudocapacitive and dielectric characteristics were reported. These nanocomposites were characterized by scanning electron microscopy, X-ray diffraction, and dynamic water sorption vapor measurements. The structural characterization of these nanostructures highlighted good crystallinity including only the rutile phase. The electrochemical characteristics were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements, which were performed in a KOH electrolyte solution. Among the Cu-doped TiO2 nanostructures that were prepared, the one containing 0.5% Cu exhibited superior electrochemical properties, including high specific gravimetric capacitance of 1183 F·g−1, specific capacitance of 664 F·g−1, energy density of 45.20 Wh·kg−1, high power density of 723.14 W·kg−1, and capacitance retention of about 94% after 100 cycles. The dielectric investigation shows good dielectric properties for all materials, where the dielectric constant and the dielectric loss decreased with the frequency increase. Thus, all the interconnected studies proved that these new materials show manifold ability and real applicative potential as pseudocapacitors and high-performance dielectrics. Future work and perspectives are anticipated for characterizing electrochemical and dielectric properties for materials including larger amounts of Cu dopant.

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“…The dispersion of ε at low frequencies and the enhancement of ε towards increasing temperatures are due to the occurrence of space-charge polarization. When the external electric field is applied, the space charges start to move and agglomerate at the contacts between the sample surfaces and electrodes used for dielectric spectroscopy measurements [51,52]. The latter effect is limited at low frequencies.…”

Section: Broadband Dielectric Spectroscopy (Bds) Studymentioning

confidence: 99%

Optimization of Nanocomposite Films Based on Polyimide–MWCNTs towards Energy Storage Applications

Chiriac¹,

Damaceanu²,

Asăndulesa³

et al. 2023

Energies

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In order to obtain polyimide-based composite materials for energy storage applications, four synthetic methods towards a polyimide matrix with 2 wt.% pristine or acid-functionalized MWCNTs have been developed. The polyimide is derived from a nitrile aromatic diamine and a fluorene-containing dianhydride which allowed the formation of flexible free-standing nanocomposite films. The films were thoroughly characterized by means of structural identification, morphology, mechanical, thermal and dielectric behavior, as well as the charge storage performance. The obtained data indicated higher homogeneity of the composites loaded with acid-functionalized MWCNTs that enabled significantly increased dielectric properties compared to the matrix. To assess the electrical charge storage capability, cyclic voltammetry and galvanostatic charge–discharge measurements were employed in a three-electrode cell configuration. Due to the higher conductivity of pristine MWCNTs compared to acid-functionalized ones, increased capability to store charges was achieved by the nanocomposites containing these fillers, despite their lower homogeneity. An attempt to increase the carbonaceous material content was made by applying a thin carbon layer onto the nanocomposite film surface, which led to higher capacitance.

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The effect of PbS quantum dots on molecular dynamics and conductivity of PTB7:PC71BM bulk heterojunction as revealed by dielectric spectroscopy

Abstract: The ternary photovoltaic blend containing the PTB7 donor component, the PC71BM acceptor component, and colloidal quantum dots of lead sulfide (PbS QDs) was investigated with broadband dielectric spectroscopy. In the...

Cited by 5 publications

References 53 publications

Electrical properties of poly(3,4-ethylenedioxythiophene) threaded by cucurbit[7]uril

Electrical properties of poly(3,4-ethylenedioxythiophene) threaded by cucurbit[7]uril

Multi-Functional Materials Based on Cu-Doped TiO2 Ceramic Fibers with Enhanced Pseudocapacitive Performances and Their Dielectric Characteristics

Optimization of Nanocomposite Films Based on Polyimide–MWCNTs towards Energy Storage Applications

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