Work Function Modification in P3HT H/J Aggregate Nanostructures Revealed by Kelvin Probe Force Microscopy and Photoluminescence Imaging

Baghgar, Mina; Barnes, Michael D.

doi:10.1021/acsnano.5b03422

Cited by 51 publications

(50 citation statements)

References 58 publications

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“…As illustrated in Fig. 4, this vertical phase separation can be a limiting factor for efficient charge transport since the HOMO level is energetically lower for a more crystalline polymer morphology, like in the bulk3031. It can result in a loss channel since the hole transport is suppressed and charge generation is getting less efficient due to a loss of wavefunction delocalization at the interface as discussed by Herrmann et al.…”

Section: Resultsmentioning

confidence: 93%

H-aggregate analysis of P3HT thin films-Capability and limitation of photoluminescence and UV/Vis spectroscopy

Ehrenreich

Birkhold

Zimmermann

et al. 2016

Sci Rep

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Polymer morphology and aggregation play an essential role for efficient charge carrier transport and charge separation in polymer-based electronic devices. It is a common method to apply the H-aggregate model to UV/Vis or photoluminescence spectra in order to analyze polymer aggregation. In this work we present strategies to obtain reliable and conclusive information on polymer aggregation and morphology based on the application of an H-aggregate analysis on UV/Vis and photoluminescence spectra. We demonstrate, with P3HT as model system, that thickness dependent reflection behavior can lead to misinterpretation of UV/Vis spectra within the H-aggregate model. Values for the exciton bandwidth can deviate by a factor of two for polymer thicknesses below 150 nm. In contrast, photoluminescence spectra are found to be a reliable basis for characterization of polymer aggregation due to their weaker dependence on the wavelength dependent refractive index of the polymer. We demonstrate this by studying the influence of surface characteristics on polymer aggregation for spin-coated thin-films that are commonly used in organic and hybrid solar cells.

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Section: Resultsmentioning

confidence: 93%

H-aggregate analysis of P3HT thin films-Capability and limitation of photoluminescence and UV/Vis spectroscopy

Ehrenreich

Birkhold

Zimmermann

et al. 2016

Sci Rep

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“…For example, the archetypal anode ITO has a WF of −4.7 eV, which is significantly higher than that of the HOMO levels (valence bands) of most common organic donor materials (e.g. P3HT , WF = −5.2 to −4.8 eV). This mismatch of energy levels leads to non‐ohmic contact and decreased hole transport.…”

Section: Role Of the Interfacial Layermentioning

confidence: 99%

Molecular design of interfacial layers based on conjugated polythiophenes for polymer and hybrid solar cells

Houston

Richeter

Clément

et al. 2017

Polymer International

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In the past two decades, bulk heterojunction organic photovoltaic (OPV) devices have emerged as attractive candidates for solar energy conversion due to their lightweight design and potential for low‐cost, high‐throughput, solution‐phase processability. Interfacial engineering is a proven efficient approach to achieve OPV devices with high power conversion efficiencies. This mini‐review provides an overview of the key structural considerations necessary when undertaking the molecular design of conjugated polyelectrolytes, for application as interfacial layers (ILs). The different roles of ILs are outlined, together with the advantages and disadvantages of competing classes of IL materials. Particular emphasis is placed on the design and synthesis of water‐soluble polythiophene‐based IL materials and the influence of their structural characteristics on their performance as a promising class of IL material. Finally, the challenges and opportunities for polythiophenes as IL materials for OPV devices and other solution‐processed solar cell technologies (e.g. perovskite solar cells) are discussed. © 2017 Society of Chemical Industry

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“…Moreover, CV measurement was explored to examine the oxidation potential and estimation of the HOMO level of developed polymer thin film as shown in Figure d. It is well reported in the literature that work function (HOMO) of conjugated polymers are directly governed by morphology which is directly associated with the thin film processing condition and the methodology adapted . Therefore, the HOMO level of developed polymer thin film was estimated using equation E HOMO = −e(4.41+ E ox(onset) )V and found to be −5.03 eV.…”

Section: Resultsmentioning

confidence: 99%

Fast Development of Self‐Assembled, Highly Oriented Polymer Thin Film and Observation of Dual Sensing Behavior of Thin Film Transistor for Ammonia Vapor

Sahu

Chandra

Pandey

et al. 2019

Macro Chemistry & Physics

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The technological demand for polymer thin film transistors (PTFTs) is continuously increasing because of their potential applications in various kinds of sensor designs. Despite this, there is need for development of a facile technique that can produce high performance low cost PTFTs. Therefore, a facile method is presented for ultrafast formation of large area self‐assembled, highly orientated, crystalline polymer thin films at high surface free energy mobile air–liquid interface named “floated polymer thin film over fluid substrate.” The grown thin film over different solid substrates is studied by multiple‐characterization techniques viz. high resolution‐transmission electron microscopy, grazing incident X‐ray diffraction, absorption spectroscopy, and cyclic voltammetry. Finally, the PTFTs having bottom gate and top contact configuration with the variations in source‐drain (S/D) electrode is fabricated for ammonia sensing. A synergistic enhanced ammonia vapor sensing performance with dual sensing characteristics through Pd‐electrode based PTFTs is observed when it is operated in two different modes of operation, that is, ON state to OFF state and vice‐versa. However, this transition is absent in Au‐electrode based PTFTs. Further, the observation of high gas response and dual sensing phenomena for ammonia vapor is argued by the evidence from a higher (approximately threefold) mobility, scanning electron microscopy (SEM), and atomic force microscopy (AFM) images.

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Work Function Modification in P3HT H/J Aggregate Nanostructures Revealed by Kelvin Probe Force Microscopy and Photoluminescence Imaging

Cited by 51 publications

References 58 publications

H-aggregate analysis of P3HT thin films-Capability and limitation of photoluminescence and UV/Vis spectroscopy

H-aggregate analysis of P3HT thin films-Capability and limitation of photoluminescence and UV/Vis spectroscopy

Molecular design of interfacial layers based on conjugated polythiophenes for polymer and hybrid solar cells

Fast Development of Self‐Assembled, Highly Oriented Polymer Thin Film and Observation of Dual Sensing Behavior of Thin Film Transistor for Ammonia Vapor

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