Carrier Dynamics in Pentacene|C<sub>60</sub> Bilayer Solar Cell Investigated through the Magnetoconductance

Omori, Takuya; Wakikawa, Yusuke; Miura, Tomoaki; Yamaguchi, Yuji; Nakayama, Keiichi I.; Ikoma, Tadaaki

doi:10.1021/jp508799j

Cited by 13 publications

(13 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…V ON of the J – V curve in dark is very close to the built-in potential estimated from the transit times that appeared in transient photocurrent for the SJ-cell (see Section S1). The dependence of MC ∞ with a peak was also observed for the SJ-cell that consisted of pentacene and fullerene in our previous report, and this is interpreted in terms of the balance between the dissociation and recombination rate constants ( k dis and k rec ) of nongeminate e–h pairs formed at the D/A-interface. In the SJ-cell, the increase in the internal electric field in the D-to-A direction (forward bias) promotes drift motions of hole and electron toward the D/A-interface, which results in promotion of recombination and inhibition of dissociation of the e–h pair; namely, the ratio k dis / k rec monotonically decreases.…”

Section: Resultssupporting

confidence: 79%

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester

et al. 2018

Self Cite

View full text Add to dashboard Cite

The magnetoconductance (MC) effect was investigated for two types of organic solar cells with single junction (SJ) and bulk junction (BJ) of poly(3-hexylthiophene) (P3HT) as donor (D) and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) as acceptor (A). Three components with different half-field-at-half-maximums ( B 1/2 ) of 4 ± 1, 20 ± 15 and >400 mT, hereafter referred to MC S,M,B in a sequence, were observed in the magnetic field dependence of the MC effects measured under dark and light conditions. The magnitude of the MC S,M,B components is sensitive to not only the junction structure of the cell but also the presence or absence of incident light. The bias voltage ( V ) dependence of the MC effect in the dark for the SJ-cell is maximized around the turn-on voltage ( V ON ) of the dark current, where a flat band condition of the active layer is achieved. The B 1/2 for the MC M component of the SJ-cell increases with V beyond V ON . In light, the BJ-cell exhibits the MC effect, whereas no effect is detected for the SJ-cell. The MC S,M components for the BJ-cell in light increase with the incident light power. The transient MC S,M components for the BJ-cell measured using a nanosecond pulse laser increases with the delay time after the flash. By integrating these phenomena and the phase of the MC effect, it is concluded that all of the MC components arise from the magnetic field effect on the spin conversion of nongeminate electron (e)–hole (h) pairs with spin-dependent charge recombinations at the D/A-interface. The B 1/2 values for MC S,M,B are, respectively, understood by the spin conversion due to the hyperfine interaction, the spin relaxation, and the g -factor difference for e (PCBM – ) and h (P3HT + ). Kinetic simulations of the MC S,M components for the BJ-cell observed at the short-circuit condition in light yield an efficiency of ca. 40% for the nongeminate recombination, which is accompanied by the generation of triplet excitons as well as relaxation to a ground singlet state. The loss mechanism of moderate triplet recombination suggests an important possibility to improve the power conversion efficiency by harvesting of the triplet excitons.

show abstract

Section: Resultssupporting

confidence: 79%

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…E–h pairs are one of the main elements that give rise to MFEs such as MC and magneto-EL in organic semiconductors, − and the degree of the MFEs is correlated with the EDMR intensity, as has recently been demonstrated . The present study shows that the EDMR intensity of intrinsic P3HT diodes is very small; thus, the P3HT diode would not be suitable for MFE application.…”

Section: Resultsmentioning

confidence: 49%

“…However, the properties of e–h pairs have recently been attracting attention. For instance, the pair has been believed to be the main element causing magnetic field effects (MFEs) (e.g., magneto-conductance and magneto-electroluminescence (EL)) in organic light-emitting diodes (OLEDs). − Also, e–h pairs have been exploited as quantum sources because they form entangled quantum states between the spin sublevels of singlet and triplet e–h pairs (SPs and TPs, respectively). − Despite such interesting features of e–h pairs, their behaviors have not been sufficiently addressed because effective experimental techniques for probing the pair have not been established. However, electrically detected and optically detected magnetic resonance (EDMR and ODMR, respectively) techniques have recently been shown to enable selective detection of e–h pairs. − The EDMR and ODMR techniques detect a change in the current and emission intensity during the ESR transition, respectively, and both signals are expected to arise from the ESR transition at the e–h pairs.…”

Section: Introductionmentioning

confidence: 99%

Electron–Hole Pairs Generated in the Crystalline Phase of Polymer Diodes Studied by Electrically Detected Magnetic Resonance Techniques

Iwamoto¹,

Hayakawa²,

Hatanaka³

et al. 2019

J. Phys. Chem. C

View full text Add to dashboard Cite

The properties of electron−hole (e−h) pairs generated in a working poly(3-hexylthiophene) (P3HT) diode are investigated by electrically detected magnetic resonance (EDMR) techniques. The EDMR intensity is shown to increase with increasing density of injected electrons for a given hole density, demonstrating that the EDMR signal arises from an e−h pair. The EDMR spectrum consists of two Gaussian curves, one of which gives a g-value very similar to that of hole carriers, suggesting that the EDMR spectrum is given by the sum of electron spin resonance (ESR) spectra from hole and electron carriers forming e−h pairs. Bias-dependent correlation between carriers and e−h pairs under diode operation is examined directly from independent measurements of near-infrared (NIR) spectroscopy for carriers and EDMR for e−h pairs. When the bias is increased to above a threshold, the EDMR signal is strongly reduced despite a gradual increase in the NIR signals, providing evidence that the e−h pairs are dissociated by an electric field in the bias region. Because of this property of the pair, the correlation between the carriers and e−h pairs inside the diode changes depending on the bias magnitude: the carriers and e−h pairs coexist or only the carriers exist. The e−h pair is presumed to be formed across different lamellae because of the crystalline phase of the P3HT film. Although the intensity of the EDMR signal from the interlamellar e−h pair is small, the intensity increases substantially when the sample is exposed to air, suggesting the formation of a magnetoreactive species that incorporates oxygen.

show abstract

“…Clarification of such an effect on the lowfield spin dynamics of long-lived RPs would make it possible for us to quantitatively extract the molecular dynamics and spin− spin interactions of the RPs from the low-field spin dynamics. Such a methodology would also contribute greatly to the analysis of electron transfer mechanisms in photofunctional materials such as organic semiconductor 26 and quantum dots, 27 which frequently exhibit MFEs due to the RP mechanism.…”

Section: Introductionmentioning

confidence: 99%

Effect of Molecular Diffusion on the Spin Dynamics of a Micellized Radical Pair in Low Magnetic Fields Studied by Monte Carlo Simulation

Miura

Murai

2015

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

Magnetic field effect is a powerful tool to study dynamics and kinetics of radical pairs (RPs), which are one of the most important intermediates for organic photon-energy conversion reactions. However, quantitative discussion regarding the relationship between the modulation of interelectron interactions and spin dynamics at low magnetic fields (<10 mT) is still an open question. We have studied the spin dynamics of a long-lived RP in a micelle by newly developed Monte Carlo simulation, in which fluctuations of the exchange and magnetic dipolar interactions by in-cage diffusion are directly introduced to the time-domain spin dynamics calculation. State-dependent relaxation/dephasing times of a few to a few tens of nanoseconds are obtained by simulations without hyperfine interactions (HFIs) as a function of the mutual diffusion constant (∼10(-6) cm(2)/s). Simulations with the HFIs exhibit incoherent singlet-triplet (S-T) mixings resulting from interplay between the HFIs and the fluctuating spin-spin interactions. The experimentally observed incoherent S-T mixing of ∼20 ns at 3 mT for a singlet-born RP in a sodium dodecyl sulfate micelle is reproduced by the simulation with reasonable diffusion coefficients. The computational method developed here contributes to quantitative detection of molecular motion that governs the recombination efficiency of RPs.

show abstract

Carrier Dynamics in Pentacene|C₆₀ Bilayer Solar Cell Investigated through the Magnetoconductance

Cited by 13 publications

References 42 publications

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester

Electron–Hole Pairs Generated in the Crystalline Phase of Polymer Diodes Studied by Electrically Detected Magnetic Resonance Techniques

Effect of Molecular Diffusion on the Spin Dynamics of a Micellized Radical Pair in Low Magnetic Fields Studied by Monte Carlo Simulation

Contact Info

Product

Resources

About

Carrier Dynamics in Pentacene|C60 Bilayer Solar Cell Investigated through the Magnetoconductance

Cited by 13 publications

References 42 publications

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C61-butyric Acid Methyl Ester

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C61-butyric Acid Methyl Ester

Electron–Hole Pairs Generated in the Crystalline Phase of Polymer Diodes Studied by Electrically Detected Magnetic Resonance Techniques

Effect of Molecular Diffusion on the Spin Dynamics of a Micellized Radical Pair in Low Magnetic Fields Studied by Monte Carlo Simulation

Contact Info

Product

Resources

About

Carrier Dynamics in Pentacene|C₆₀ Bilayer Solar Cell Investigated through the Magnetoconductance

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester

Magnetoconductance Study on Nongeminate Recombination in Solar Cell Using Poly(3-hexylthiophene) and [6,6]-Phenyl-C₆₁-butyric Acid Methyl Ester