Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

McLeod, John A.; Pitman, Amy L.; Kurmaev, E.Z.; Finkelstein, L. D.; Savva, Achilleas; Moewes, A.

doi:10.1063/1.4936898

Cited by 19 publications

(17 citation statements)

References 51 publications

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“…Although the absolute values of the HOMO‐LUMO gap differ significantly between PBE, B3LYP, and ω B97X, the overall trend of an increased gap with increasing departure from planarity of the P3HT oligomer is maintained by all xc functionals. Other theoretical studies report values of 1.81 and 1.99 eV for the HOMO‐LUMO gap in isolated P3HT and 0.37 eV for the P3HT/PCBM mixture using GGA functionals. Experimental work has reported band gaps of 2.1‐2.5 eV for P3HT and a band gap of 2.6 eV for a P3HT/PCBM mixture .…”

Section: Resultsmentioning

confidence: 97%

“…Other theoretical studies report values of 1.81 and 1.99 eV for the HOMO‐LUMO gap in isolated P3HT and 0.37 eV for the P3HT/PCBM mixture using GGA functionals. Experimental work has reported band gaps of 2.1‐2.5 eV for P3HT and a band gap of 2.6 eV for a P3HT/PCBM mixture . The B3LYP HOMO‐LUMO gap is closest to the experimental band gap values for the isolated P3HT and the P3HT/PCBM mixture.…”

Section: Resultsmentioning

confidence: 97%

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Van der Waals effects on structure and optical properties in organic photovoltaics

Götz

Rodríguez

Castillo-Alvarado

et al. 2019

Int J of Quantum Chemistry

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We have recently reported that dispersion forces can have drastic effects on the structure and charge separation in organic photovoltaics (OPVs) (Martinez et al., J. Phys. Chem. C 121, 20 134 [2017]). Here we investigate dimer complexes formed by the polymer P3HT and the fullerene derivative PCBM. We show how van der Waals (vdW) interactions affect the geometrical structure, which has strong effects on the electronic structure and UV‐Vis absorption spectrum. Time‐dependent density functional theory calculations demonstrate that the experimentally observed blue‐shift of the absorption maximum of P3HT/PCBM OPV cells with respect to pure P3HT results mainly from distortions in P3HT due to vdW interactions between donor and acceptor fragments. Reduced absorption in the red region of the UV‐Vis spectrum results from distortions of P3HT and small charge transfer between P3HT and PCBM. These results are in qualitative agreement with experiments and recent theoretical results on the corresponding solid‐state films.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 97%

Van der Waals effects on structure and optical properties in organic photovoltaics

Götz

Rodríguez

Castillo-Alvarado

et al. 2019

Int J of Quantum Chemistry

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“…As can be observed, three emission peaks of P3HT centered at 648 nm 710 and 780 nm, which correspond to the vibronic structures of P3HT. The PL emission peak at about 648 nm (1.91 eV) is associated with pure electronic transition of P3HT and the peaks at 710 nm (1.74 eV) to the first vibronic band [25][26][27]. However, the PL emission at 780 nm (1.5 eV) shows an order in the lamellar structure of P3HT, which could promote vertical segregation of P3HT and PCBM molecules and as a consequence the electronic communication between the donor and acceptor layers.…”

Section: Electrical and Photophysical Characterization Of Penmentioning

confidence: 99%

Morphological and micro-structural interface characterization in multilayer inverted polymer-fullerene bulk heterojunction solar cells

Jouane

Moubah

Schmerber

et al. 2018

Solar Energy Materials and Solar Cells

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Inverted polymer solar cells based on P3HT/PCBM bulk heterojunction were prepared on flexible polyethylene naphthalate (PEN) substrate. The effect of annealing of the PEN/ITO/ZnO multilayer and ZnO/P3HT:PCBM on the structural, morphological, photophysical and photovoltaic properties was investigated and scrutinized directly on the OPV devices using atom probe tomography (APT), scanning electron microscopy (SEM) and microfocus X-rays techniques. We carried out a 3D reconstruction of the interfaces of the multilayer containing PEN/ITO, ZnO/ITO and P3HT:PCBM/ZnO to address the interface micro-structure and its influence on the morphology of the photoactive film. The analyses show that the morphology of the interfaces is affected by the structure of each layer of the BHJ devices causing orientation of P3HT crystals with PCBM aggregates and ZnO, which in turn leads to a significant change of the charge transport across each layer and therefore photovoltaic performances.

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“…This can be attributed to order aggregation resulting from the presence of hydrogen bonding (Xiao et al, 2014). In BHJ organic solar cells, electron donor and acceptor molecules are mixed to fabricate films used as active layers (McLeod et al, 2015;You et al, 2011). The donor phase aggregated by PDAK molecules in the active layer would be similar to the structure of the film of PDAK; therefore, the UV-Vis absorption spectrum of the PDAK film may be used to evaluate optical absorption and molecular orbital energy levels.…”

Section: Optical Properties Of Pdakmentioning

confidence: 99%

Optical properties of (Z)-2-(2-phenylhydrazinylidene)acenaphthen-1(2H)-one: a potential electron donor in organic solar cells

Zhang

Ming

2017

Acta Crystallogr C Struct Chem

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Electron-donating molecules play an important role in the development of organic solar cells. (Z)-2-(2-Phenylhydrazinylidene)acenaphthen-1(2H)-one (PDAK), CHNO, was synthesized by a Schiff base reaction. The crystal structure shows that the molecules are planar and are linked together forming `face-to-face' assemblies held together by intermolecular C-H...O, π-π and C-H...π interactions. PDAK exhibits a broadband UV-Vis absorption (200-648 nm) and a low HOMO-LUMO energy gap (1.91 eV; HOMO is the highest occupied molecular orbital and LUMO is the lowest unoccupied molecular orbital), while fluorescence quenching experiments provide evidence for electron transfer from the excited state of PDAK to C. This suggests that the title molecule may be a suitable donor for use in organic solar cells.

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Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

Cited by 19 publications

References 51 publications

Van der Waals effects on structure and optical properties in organic photovoltaics

Van der Waals effects on structure and optical properties in organic photovoltaics

Morphological and micro-structural interface characterization in multilayer inverted polymer-fullerene bulk heterojunction solar cells

Optical properties of (Z)-2-(2-phenylhydrazinylidene)acenaphthen-1(2H)-one: a potential electron donor in organic solar cells

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