Hole-injection barrier across the intermolecular interaction mediated interfacial DNTT layer

Mandal, Subhankar; Roy, Saugata; Saifuddin,; Hazra, S.

doi:10.1016/j.apsusc.2022.153696

Cited by 5 publications

(20 citation statements)

References 40 publications

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“…With thermal annealing, though the coverage of the interfacial layer increases but the coverage of the crystalline domains above it decreases. 26 This kind of molecular orientation was also observed in pentacene molecular thin films on the HOPG surface. 29,35 The ϕ Bh in the 3 Å DNTT/HOPG film was found around 1.3 eV and no significant change was observed due to the increase in the film thickness and also after thermal annealing.…”

Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 61%

“…32 Subsequently, the DNTT layers of different cumulative nominal thickness (D CN = 3, 6, 9, 16, and 32 Å) were deposited on it in steps and annealed at 100 °C for 1 h was used as a reference level to calibrate the XPS spectra of the films. 26,32 The PeakFit, CasaXPS, and OriginPro software were used for analyzing the spectroscopic data. The well-known Shirley method was used for the XPS background subtraction, whereas the Gaussian−Lorentzian sum function was used to fit all the XPS core-level spectra.…”

Section: Methodsmentioning

confidence: 99%

“…Atomic force microscopy (AFM) images or topography of the DNTT film on HOPG, as reported before, however, suggests that the coverage of the DNTT molecular layer is very low and it gets even lower with thermal annealing. 26 These complementary results essentially suggest that the DNTT molecules adsorbed on the HOPG substrate in flat-lying orientation to form an interfacial layer and then form small dewetted domains of bulk crystalline structure due to the interfacial stress arising from the miss-match in the molecular orientation between the interfacial layer and the bulk crystalline domain layer. With thermal annealing, though the coverage of the interfacial layer increases but the coverage of the crystalline domains above it decreases.…”

Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 95%

“…29,34 This actually reflects the non-active nature of the HOPG surface and eliminates the possibility of formation of any interfacial dipole. 26,32 Such non-active nature of the HOPG surface toward organic molecules actually reduces the unintentional interaction at the interface, which is useful to study the molecular dipole-induced effect and thus makes it a perfect choice as a substrate.…”

Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 99%

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Molecular Dipole Layer and Alkyl Side-Chain Induced Improvement in the Energy Level Alignment and Wetting of Dinaphthothienothiophene Thin Films

Mandal,

Jana,

Roy

et al. 2023

J. Phys. Chem. C

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The evolution of electronic structures and morphology of dinaphthothienothiophene (DNTT) thin films on highly oriented pyrolytic graphite, due to the incorporation of a polar chlorogallium phthalocyanine (ClGaPc) molecular layer at the interface, substitution of DNTT with alkyl side-chain-incorporated S-shaped DNTT (S-DNTT-C10), and thermal annealing, were investigated using photoelectron spectroscopic techniques to check the possibility of proper energy level alignment at the metal− organic interface, which is one of the key challenges to improve the charge transport in organic semiconductor-based devices. A significant modulation in the vacuum level (VL) and a small downward shift in the highest occupied molecular orbital (HOMO) level with an intermediate charge injection level (CIL) are evident in the DNTT thin film due to the incorporation of the ClGaPc layer at the interface. This is a clear signature of the molecular dipole layer (of well-ordered Cl-up orientated ClGaPc molecules)-induced realignment of the molecular energy levels of the DNTT thin films. On the other hand, a noticeable downward shift in the VL, a signature of an improvement in the bulk coverage, is evident in the S-DNTT-C10 film, which can be attributed to the presence of aliphatic hydrocarbons in the alkyl side-chain incorporated molecule. Furthermore, a double-peak-like HOMO level is evident in the S-DNTT-C10 film, which can be attributed to the two distinct orientations/arrangements of the molecules, one at the interface and other in the remaining part of the film. The formation of an intermediate CIL, through incorporation of a molecular dipole layer at the interface, is helpful to overcome the large hole injection barrier, while the enhancement of molecular coverage at the metal−organic interface and thereafter, through molecular engineering, is useful to increase the hole injection area, both of which are of immense importance in improving the device performances.

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Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 95%

Section: Ups Study Of Dntt/hopg Systemmentioning

confidence: 99%

See 2 more Smart Citations

Molecular Dipole Layer and Alkyl Side-Chain Induced Improvement in the Energy Level Alignment and Wetting of Dinaphthothienothiophene Thin Films

Mandal,

Jana,

Roy

et al. 2023

J. Phys. Chem. C

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“…Semiconducting organic molecules and polymers open an alternate path for the development of devices featuring low cost, easy fabrication, light weight, and high flexibility. − Owing to the solution processing ability and commercial prospect, poly(3-hexylthiophene) [P3HT] has been studied extensively as one of the more promising semiconducting polymers for organic thin-film transistors (OTFTs). − However, P3HT forms a semicrystalline morphology consisting of crystalline and amorphous regions. Hence, the orientation (edge-on or face-on), amount (fraction of crystallites), and quality (planarity, local order, and average conjugation length) of the crystalline aggregates and the interconnection between the aggregates, especially near the film–substrate interface, play significant roles in tuning the charge carrier mobility. − On the other hand, nanomaterials (NMs), like nanoparticles (NPs) or nanorods (NRs), are space-confined objects, which show distinguishing properties as compared to their bulk counterpart. , …”

Section: Introductionmentioning

confidence: 99%

Nanoparticle Mediated Improved Crystallinity and Connectivity of Semiconducting Polymer Thin Films

Saifuddin

Biswas

Roy

et al. 2023

ACS Appl. Polym. Mater.

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Polymer nanocomposites (PNCs), i.e., nanoparticle (NP) incorporated semiconducting polymers (SPs), constitute a class of active materials where the dispersion and locations of the NPs and the crystallinity of the SPs play important roles in deciding their device performances. Herein Au nanoparticle (AuNP) mixed poly(3-hexylthiophene) [P3HT] was taken as a model PNC system, and a unique combination of complementary techniques was utilized to address these dispersion-related structural issues, viz the organization and/or dispersion of AuNPs, its evolution with thermal annealing (TA), and their effects on the ordering or crystallization of the P3HT matrix. The layering of AuNPs near the interfaces, namely confined or near monolayer thick layer at the film−substrate interface and fluctuated or near bilayer thick layer at the film−air interface, are evident in the as-cast PNC thin films, indicating self-organization and phase separation tendencies of the similar and dissimilar materials (i.e., dominant decrease of enthalpic energy over entropy) and different (hard and soft) boundary conditions of the interfaces. On the other hand, appreciable dispersion of AuNPs inside P3HT matrix is evident after TA, suggesting thermal energy induced diffusion of AuNPs through amorphous P3HT regions, overcoming the selforganization and phase separation (i.e., dominant increase of entropic energy over enthalpy). Such dispersion enhances the quantity (fraction or amount) and quality (planarity or conjugation length) of P3HT crystallites (and thus validates the dispersion of AuNPs in the amorphous P3HT regions) and their edge-on orientation and connectivity. This information or understanding is very useful for optimizing the structures of the PNC-based active layers for their better charge carrier mobility and device performances.

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Sputter-cleaning modified interfacial energetic and molecular structure of DNTT thin film on ITO substrate

Jana,

Mandal,

Roy

et al. 2024

Applied Surface Science

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Hole-injection barrier across the intermolecular interaction mediated interfacial DNTT layer

Cited by 5 publications

References 40 publications

Molecular Dipole Layer and Alkyl Side-Chain Induced Improvement in the Energy Level Alignment and Wetting of Dinaphthothienothiophene Thin Films

Molecular Dipole Layer and Alkyl Side-Chain Induced Improvement in the Energy Level Alignment and Wetting of Dinaphthothienothiophene Thin Films

Nanoparticle Mediated Improved Crystallinity and Connectivity of Semiconducting Polymer Thin Films

Sputter-cleaning modified interfacial energetic and molecular structure of DNTT thin film on ITO substrate

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