Blend ratio and applied voltage effects on the charge recombination in bulk heterojunction polymer solar cells based on anthracene-containing poly(arylene-ethynylene)-alt-poly(arylene-vinylene) studied using magnetoconductance

Radaoui, M.; Taboubi, Oumayma; Fredj, A. Ben; Romdhane, S.; Egbe, Daniel Ayuk Mbi; Bouchriha, H.

doi:10.1016/j.jpcs.2021.110190

Cited by 4 publications

(4 citation statements)

References 52 publications

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“…As the magnetic field is increased, the amount of pair states mixed with the singlet state decreases, resulting in a decrease in singlet e–h pair recombination and, as a result, an increase in current. To calculate the recombination probability P r , we use the Stochastic Liouville equation (SLE) in the framework of the e–h pair model to calculate the density matrix from its equation of motion. − The first term is the Liouville term, which describes how the density matrix evolves under the influence of the system’s Hamiltonian H . Hyperfine interactions ( ) and Zeeman splitting of the triplets ( ), where g ≈ 2 is the polaron g factor, μ B is the Bohr magneton, H⃗ app is the applied magnetic field, H⃗ hyp, i is the hyperfine field, S⃗ i is the spin operator of the individual polarons, and i denotes electron or hole, are included in this Hamiltonian.…”

Section: Results and Discussionmentioning

confidence: 99%

Static, Dynamic, Dielectric, and Magnetic Investigations on AnE-PVstat: PCBM Polymer Solar Cells under Open-Circuit Conditions

et al. 2021

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We report on the enhancement in the efficiency of inverted polymer solar cells because of increased open-circuit voltage and short-circuit current by using an electron collecting an interfacial layer of an aluminum-doped zinc oxide (AZO). The efficiency of polymer solar cells comprising a bulk heterojunction photoactive film of an anthracene containing poly(p-aryleneethynylene)-alt-poly(p-arylenevinylene)/1-(3methoxycarbonyl)propyl-1-phenyl [6,6] and phenyl-C 60 -butyric acid methyl ester has increased from 3.6% to 4.6% from the standard to the inverted architecture with Al concentrations of 0.6%, respectively. After this concentration, the efficiency starts to decrease. The reasons for these results are discussed based on the AC electrical process and magnetoconductance (MC) measurements under open-circuit conditions at room temperature. The frequency ( f) dependence of the real part (Z′) and the imaginary part (Z′′) of the complex impedance with various Al concentrations at open-circuit conditions at room temperature show three f regimes: low, mid, and high f. The Cole−Cole plots (Z′′ vs Z′) demonstrate an increase in the semicircle radius from the standard to the inverted architectures for Al concentrations of 0.2% and 0.6%, respectively. After this concentration (0.6%), the semicircle radius starts to decrease. Afterward, the present proposed impedance model shows some important physical parameters such as electron diffusion time (τ diff ), the recombination time (τ rec ), the diffusion constant (D n ), the diffusion length (L n ), and the electron mobility (μ n ). From the dielectric measurements, all devices have a unique relaxation process, which is the property of the Debye relaxation mechanism. Moreover, the dielectric constant (ε′) showed a strong dependence on f and the type of architecture. In addition, the dielectric loss (ε″) decreased significantly with f, and as a result, it has sparked a lot of interest in these materials' possible uses in electrical energy storage. The dielectric loss tangent (tan(δ))) peaks shifted a little bit toward higher f from the standard to the inverted structures, indicating reduction of relaxation time. Furthermore, we found an MC memory effect in the inverted cells. Then the mechanism responsible for the MC was determined with the current density versus the applied voltage in the log−log scale for the different elaborated cells at V OC . The results suggested that the applied voltage (V OC ) corresponds to the trapped charge limited current (TCLC) regime, with traps acting as recombination centers for electron−hole (e−h) pairs, preventing the formation of double carriers MC. For this reason, the MC in the device may be described using a stochastic Liouville equation in the context of the e−h pair model.

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Section: Results and Discussionmentioning

confidence: 99%

Static, Dynamic, Dielectric, and Magnetic Investigations on AnE-PVstat: PCBM Polymer Solar Cells under Open-Circuit Conditions

et al. 2021

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“…could take place under spin thermal equilibrium conditions at room temperature [4,16], which is different from that of those inorganic giant magnetoresistances (MRs) generated by spin polarization. This implies that new mechanisms are responsible for OMR [17][18][19][20][21][22]. So far, three typical mechanisms have been mainly invoked to interpret the OMR phenomenon: the bipolaron model, the exciton-charge interaction model and the singlet-triplet conversion (STC) model.…”

Section: Introductionmentioning

confidence: 99%

“…In this model, the interaction between excitons and charges with spin of 1/2 is B dependent, causing a negative or positive OMR. The STC model was generally used to explain OMR in devices with bipolar carrier injection [20,21]. When a magnetic field suppresses the spin mixing between singlet and triplet excitons by hyperfine fields, OMR is generated since the singlets are easier to dissociate and recombine than triplets.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature organic magnetoresistance based on interfacial ground charge transfer state

Qu,

Qiao,

et al. 2023

J. Phys. D: Appl. Phys.

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We propose the organic magnetoresistance (OMR) based on weak interfacial ground charge transfer (IGCT) state at m-MTDATA/Alq3 heterojunction. The maximum OMR reaches 13.2% at room temperature under the external magnetic field of 300 mT, which is well interpreted by the different roles of singlet and triplet IGCT states in hole transport. As demonstrated, the hole transport is blocked by the singlet IGCT and passed through by the triplet IGCT. By manipulating the Larmor frequencies (∆ω=∆gµBB/ℏ) of mixing singlet and triplet IGCT states through Δg mechanism under external magnetic field, the hole current is modulated, thus generating OMR. Furthermore, OMR can be further enhanced to 15.4% at 300 mT and 27.9% at 1000 mT by inserting a thin BCP interlayer between m-MTDATA and Alq3 layers. This picture will help to implement a giant OMR by interfacial CT states in the future.

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“…Moreover, the low carrier mobilities of the conducting polymers and the short lifetime of the exciton restrict the active layer thickness below 200 nm, so it is not possible to boost optical absorption by merely increasing the thickness [8][9][10][11][12][13][14]. Thus, in addition to the absorber layer composition and device architecture, the PCE in TFPSCs depends on the augmentation of the open-circuit voltage and the fill factor (FF) [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Suppressing charge recombination in disordered polymers blend medium

Hamed

Abdallah

Mola

2023

J. Phys. D: Appl. Phys.

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Charge recombination is one of the critical factors that inﬂuence the performance of thin ﬁlm polymer solar cells (TFPSC). In this investigation metal, plasmonic nano-particles are employed to suppress charge recombination and energy loss in TFPSC. Trimetallic nano-composite was successfully synthesized, composed of copper, nickel, and silver (Cu/Ni/Ag) using wet chemistry. The nano-composite was incorporated into polymer based solar absorber layers at diﬀerent concentrations. The absorber layer is a fullerene-based bulk-heterojunction design using poly-3-hexylthiophene (P3HT) donor polymer. The results show that the power conversion eﬃciency (PCE) of the device doped with nano-composite has improved by 85% compared to the undoped one. The incorporation of tri-metallic nano-composite into the polymer blend solar absorber resulted in enhanced optical absorption and improved collection of photo-current as reﬂected by recorded high short circuit current density (Jsc) and ﬁll factor (FF). The enhancement of the performance is due to the occurrence of local surface plasmon resonances in polymer medium. The experiment indicated that there is some increment in an open circuit voltage, which is attributed to the low energy losses as the result of improved exciton dissociation, charge carrier transport, and collection.

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Blend ratio and applied voltage effects on the charge recombination in bulk heterojunction polymer solar cells based on anthracene-containing poly(arylene-ethynylene)-alt-poly(arylene-vinylene) studied using magnetoconductance

Cited by 4 publications

References 52 publications

Static, Dynamic, Dielectric, and Magnetic Investigations on AnE-PVstat: PCBM Polymer Solar Cells under Open-Circuit Conditions

Static, Dynamic, Dielectric, and Magnetic Investigations on AnE-PVstat: PCBM Polymer Solar Cells under Open-Circuit Conditions

Room-temperature organic magnetoresistance based on interfacial ground charge transfer state

Suppressing charge recombination in disordered polymers blend medium

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