Variations of the elastic modulus perpendicular to the surface of rubrene bilayer films

Jhou, Yen Wei; Yang, Chun Kai; Sie, Siang Yu; Chiu, Hsiang Chih; Tsay, Jyh-Jong

doi:10.1039/c8cp07062h

Cited by 11 publications

(16 citation statements)

References 44 publications

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“…We found qualitatively similar results in all simulations. This is reasonable as halide perovskites have surprisingly low Young's moduli for inorganic semiconductors, comparable to those of relevant organic crystals [37][38][39][40] .…”

Section: Tetracene Molecules On Halide Perovskite Surfacesmentioning

confidence: 66%

“…The distance between adjacent halide perovskite and adjacent tetracene layers was at least as large as the vacuum spacing required to prevent interaction between adjacent layers of the same material in the non-periodic direction. As tetracene and halide perovskites have comparable Young's moduli, we allowed lattice parameters to vary in geometry relaxations 37,38 .…”

Section: Tetracene-halide Perovskite Thin Film Interfacementioning

confidence: 99%

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A study of singlet fission-halide perovskite interfaces

Bowman¹,

Stranks²,

Monserrat³

2021

Preprint

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Singlet fission/halide perovskite interfacesA method for improving the efficiency of solar cells is combining a low-bandgap semiconductor with a singlet fission material (which converts one high energy singlet into two low energy triplets following photoexcitation). Here we present a study of the interface between singlet fission molecules and low-bandgap halide pervoskites. We briefly show a range of experiments screening for triplet transfer into a halide perovskite. However, in all cases triplet transfer was not observed. This motivated us to understand the halide perovskite/singlet fission interface better by carrying out first-principles calculations using tetracene and cesium lead iodide. We found that tetracene molecules/thin films preferentially orient themselves parallel to/perpendicular to the halide perovskite's surface, in a similar way to on other inorganic semiconductors. We present formation energies of all interfaces, which are significantly less favourable than for bulk tetracene, indicative of weak interaction at the interface. It was not possible to calculate excitonic states at the full interface due to computational limitations, so we instead present highly speculative toy interfaces between tetracene and a halide-perovskite-like structure. In these models we focus on replicating tetracene's electronic states correctly. We find that tetracene's singlet and triplet energies are comparable to that of bulk tetracene, and the triplet is strongly localised on a single tetracene molecule, even at an interface. Our work provides new understanding of the interface between tetracene and halide perovskites, explores the potential for modelling excitons at interfaces, and begins to explain the difficulties in extracting triplets directly into inorganic semiconductors.

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Section: Tetracene Molecules On Halide Perovskite Surfacesmentioning

confidence: 66%

Section: Tetracene-halide Perovskite Thin Film Interfacementioning

confidence: 99%

A study of singlet fission-halide perovskite interfaces

Bowman¹,

Stranks²,

Monserrat³

2021

Preprint

View full text Add to dashboard Cite

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“…The topographical and nanomechanical properties of PANI-SBu thin films were investigated simultaneously by using the PeakForce quantitative nanomechanical property mapping (PF-QNM) technique with an atomic force microscope (MultiMode 8, Bruker, Santa Barbara, CA, USA). The PF-QNM technique has been widely used to study the nanomechanical properties of soft matter, polymers, and organic semiconductors. − The accuracies of the obtained elastic moduli are comparable to those acquired using the conventional instrumented nanoindentation testing methods . During the PF-QNM experiment, the AFM cantilever approaches the sample from approximately 150 nm above the sample surface.…”

Section: Materials and Methodsmentioning

confidence: 90%

Correlation between Nanoscale Elasticity, Semiconductivity, and Structural Order in Functionalized Polyaniline Thin Films

et al. 2020

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The correlation between structural order, elasticity, and semiconductivity for butylthio-functionalized polyaniline (PANI-SBu) thin films was investigated using atomic force microscopy (AFM)-based techniques with X-ray diffraction (XRD) and scanning electron microscopy (SEM). After different stirring times, the thin films were cast from the solution of PANI-SBu in N-methyl-2-pyrrolidone that was continuously stirred at a constant rate of 150 rpm in an airtight round-bottom flask. According to the XRD and SEM results, the cross-sectional film structure evolved from being generally holey to highly lamellar with an increase in the stirring time. However, some new types of disordered structures began emerging beyond the optimal stirring time, possibly caused by the formation of disordered packing structures as contributed from the overoxidized polyaniline backbones during the additional stirring time. Moreover, according to the investigation results obtained using AFM-based techniques, the outof-plane elastic moduli and charge mobilities of the PANI-SBu films were consistently smaller for disordered thin films and larger for structurally more ordered ones. The shear force resulting from the mechanical stirring of the PANI-SBu solution may gradually disentangle the polymer chains and thus help transform the individual polyaniline molecule from a coil-like chain conformation to a better extended rodlike chain conformation. Therefore, when cast into a film, the stretched polymer chains facilitate self-organization among the PANI-SBu backbones during the film formation process. Thus, an improved structural order in the film is attained. Our results demonstrate an unambiguous correlation between the structure order, elasticity, and conductivity in PANI-SBu thin films, which may have useful applications in conducting polymer-based flexible electronics.

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“…As tetracene and halide perovskites have comparable Young’s moduli, we allowed lattice parameters to vary in geometry relaxations. 41 , 42 …”

Section: Tetracene–halide Perovskite Thin-film Interfacementioning

confidence: 99%

Investigation of Singlet Fission–Halide Perovskite Interfaces

2022

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A method for improving the efficiency of solar cells is combining a low-band-gap semiconductor with a singlet fission material (which converts one high-energy singlet into two low-energy triplets following photoexcitation). Here, we present a study of the interface between singlet fission molecules and low-band-gap halide pervoskites. We briefly present 150 experiments screening for triplet transfer into a halide perovskite. However, in all cases, triplet transfer was not observed. This motivated us to understand the halide perovskite–singlet fission interface better by carrying out first-principles calculations using tetracene and cesium lead iodide. We found that tetracene molecules/thin films preferentially orient themselves parallel to/perpendicular to the halide perovskite’s surface. This result is in agreement with simulations of tetracene (and other rodlike molecules) on a wide range of inorganic semiconductors. We present formation energies of all interfaces, which are significantly less favorable than for bulk tetracene, indicative of weak interaction at the interface. It was not possible to calculate excitonic states at the full interface due to computational limitations, so we instead present highly speculative toy interfaces between tetracene and a halide-perovskite-like structure. In these models, we focus on replicating tetracene’s electronic states correctly. We find that tetracene’s singlet and triplet energies are comparable to that of bulk tetracene, and the triplet is strongly localized on a single tetracene molecule, even at an interface. Our work provides new understanding of the interface between tetracene and halide perovskites, explores the potential for modeling excitons at interfaces, and begins to explain the difficulties in extracting triplets directly into inorganic semiconductors.

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Variations of the elastic modulus perpendicular to the surface of rubrene bilayer films

Abstract: We propose a structural bilayer model successfully explaining the layered nature or characteristics of rubrene films.

Cited by 11 publications

References 44 publications

A study of singlet fission-halide perovskite interfaces

A study of singlet fission-halide perovskite interfaces

Correlation between Nanoscale Elasticity, Semiconductivity, and Structural Order in Functionalized Polyaniline Thin Films

Investigation of Singlet Fission–Halide Perovskite Interfaces

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