Merocyanines for vacuum-deposited small-molecule organic solar cells

Chen, Ko-Wei; Huang, Chong-Wei; Lin, Shao-Yu; Liu, Yi-Hung; Chatterjee, Tanmay; Hung, Wen‐Yi; Liu, Shun‐Wei; Wong, Ken‐Tsung

doi:10.1016/j.orgel.2015.07.050

Cited by 15 publications

(2 citation statements)

References 42 publications

(52 reference statements)

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“…The quantitative prediction and comprehension of low-lying excitations in MC molecules are fundamentally interesting and technologically important. For instance, the calculation of excitation energies provides valuable insights into the photophysical properties of MCs, ,, including absorption spectra, , fluorescence emission, and photochemical behavior. , A standard approach to calculating molecular excitation spectra is time-dependent density-functional theory (TD-DFT) based on various density-functional approximations (DFA). In previous studies, it was found that the first excitation energy is overestimated by about 0.3 eV with TD-DFT, even with fourth-rung DFA such as CAM-B3LYP .…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Optoelectronic Properties of Merocyanine-Dyes

Tomar,

Bernasconi,

Fazzi

et al. 2023

J. Phys. Chem. A

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Merocyanines, as prototypes of highly polar π-conjugated molecules, have been intensively investigated for their self-assembly and optoelectronic properties, both experimentally and theoretically. However, an accurate description of their structural and electronic properties remains challenging for quantum-chemical methods. We assessed several theoretical approaches, TD-DFT, GW-BSE, STEOM-DLPNO-CCSD, and CASSCF/ NEVPT2-FIC for their reliability in reproducing optoelectronic properties of a series of donor/acceptor (D/A) merocyanines, focusing on the first excitation energy. Additionally, we tested an all-electron perturbative method based on time-dependent coupled-perturbed density functional theory, denoted as TDCP-DFT. Particular focus was set on direct and indirect solvent effects, which affect excited-state energies by electrostatic interaction and molecular geometry. The molecular configuration space was sampled at the semiempirical tight-binding level. Our results corroborate previous investigations, showing that the S 0 − S 1 excitation energy strongly depends on the merocyanine molecular structure and the dielectric constant of the solvent. We found significant effects of the polar solution environment on the geometry of the merocyanines, which strongly affect the calculated excitation energies. Taking these effects into account, the best agreement between calculated and measured excitation energies was obtained with TDCP-DFT and GW-BSE. We also calculated excitation energies of molecular crystals at the TDCP-DFT level and compared the results to the corresponding monomers.

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Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Optoelectronic Properties of Merocyanine-Dyes

Tomar,

Bernasconi,

Fazzi

et al. 2023

J. Phys. Chem. A

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“…Such configuration allows for using small molecules and deposition under vacuum. Small molecules have a number of benefits such as easy preparation and purification and a unique final molecule that prevents the problem of batch-to-batch reproducibility [13][14][15]. Furthermore, the thermal deposition technique allows for easy fabrication of multilayer devices with precise control of the thickness of each layer [16,17].…”

Section: Introductionmentioning

confidence: 99%

Semi-Transparent Organic Photovoltaic Cells with Dielectric/Metal/Dielectric Top Electrode: Influence of the Metal on Their Performances

et al. 2021

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In order to grow semi-transparent organic photovoltaic cells (OPVs), multilayer dielectric/metal/dielectric (D/M/D) structures are used as a transparent top electrode in inverted OPVs. Two different electrodes are probed, MoO3/Ag/MoO3 and MoO3/Ag/Cu:Ag/ZnS. Both of them exhibit high transmission in visible and small sheet resistance. Semi-transparent inverted OPVs using these electrodes as the top anode are probed. The active organic layers consist in the SubPc/C60 couple. The dependence of the OPV performances on the top electrode was investigated. The results show that far better results are achieved when the top anode MoO3/Ag/MoO3 is used. The OPV efficiency obtained was only 20% smaller in comparison with the opaque OPV, but with a transparency of nearly 50% in a broad range of the visible light (400–600 nm). In the case of MoO3/Ag/Cu:Ag/ZnS top anode, the small efficiency obtained is due to the presence of some Cu diffusion in the MoO3 layer, which degrades the contact anode/organic material.

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The Influence of Deposition Rates on Properties of AlPcCl Thin Films and on the Performance of Planar Organic Solar Cells

Mohammed-Krarroubik

Morsli

Khelil

et al. 2017

Physica Status Solidi (a)

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The performance of organic photovoltaic cells depends on different properties of the organic materials, such as carrier mobility, band structure, morphology, and crystallinity. For AlPcCl, it is shown that these properties are dependent on the layer deposition rates. As the deposition rate increases, the surface roughness of AlPcCl layers decreases. In contrast, the crystallinity of the layers increases as the deposition rate decreases, thereby increasing the hole mobility value. These effects are opposed: the former effect allows higher open circuit voltages to be obtained as the deposition rate increases, whereas the latter increases the short circuit current as the deposition rate decreases. Therefore, there is a trade‐off between open and short circuit current values, and it is necessary to find the best deposition rate for AlPcCl. Here, it is shown that the highest mobility carriers in layers deposited slowly allow the use of thicker AlPcCl layers, which permits acceptable open circuit voltage values and optimum photovoltaic cell efficiencies to be obtained. This results in an optimum efficiency value of 3.97% for a 26‐nm‐thick AlPcCl film that is deposited at 0.02–0.03 nm s−1.

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Merocyanines for vacuum-deposited small-molecule organic solar cells

Cited by 15 publications

References 42 publications

Theoretical Study on the Optoelectronic Properties of Merocyanine-Dyes

Theoretical Study on the Optoelectronic Properties of Merocyanine-Dyes

Semi-Transparent Organic Photovoltaic Cells with Dielectric/Metal/Dielectric Top Electrode: Influence of the Metal on Their Performances

The Influence of Deposition Rates on Properties of AlPcCl Thin Films and on the Performance of Planar Organic Solar Cells

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