A grand challenge in materials science is to identify the impact of molecular composition and structure across a range of length scales on macroscopic properties. We demonstrate a unified ...experimental-theoretical framework that coordinates experimental measurements of mesoscale structure with molecular-level physical modeling to bridge multiple scales of physical behavior. Here we apply this framework to understand charge transport in a semiconducting polymer. Spatially-resolved nanodiffraction in a transmission electron microscope is combined with a self-consistent framework of the polymer chain statistics to yield a detailed picture of the polymer microstructure ranging from the molecular to device relevant scale. Using these data as inputs for charge transport calculations, the combined multiscale approach highlights the underrepresented role of defects in existing transport models. Short-range transport is shown to be more chaotic than is often pictured, with the drift velocity accounting for a small portion of overall charge motion. Local transport is sensitive to the alignment and geometry of polymer chains. At longer length scales, large domains and gradual grain boundaries funnel charges preferentially to certain regions, creating inhomogeneous charge distributions. While alignment generally improves mobility, these funneling effects negatively impact mobility. The microstructure is modified in silico to explore possible design rules, showing chain stiffness and alignment to be beneficial while local homogeneity has no positive effect. This combined approach creates a flexible and extensible pipeline for analyzing multiscale functional properties and a general strategy for extending the accesible length scales of experimental and theoretical probes by harnessing their combined strengths.
A model reduction scheme for polymer semiconductors is presented that can be utilized to compute intra‐chain charge‐carrier mobility from the monomer sequence. The reduced model can be used in ...conjunction with any quantum dynamics approach, but it is explored here assuming that transport takes place through incoherent hopping events between states of different degrees of delocalization. The procedure is illustrated by considering 28 realistic polymers for which a quantitative correlation is established between charge localization characteristics and charge mobility. The data set helps in establishing plausible ranges for all the microscopic parameters of the model and it can therefore be used to determine the maximum plausible improvement in mobility. The reduced model is also used to provide some insight on the observation that the highest mobility polymers do not have very broad valence bands: there is indeed a range of the inter‐monomer coupling for which this parameter has little effect on the mobility.
An effective model reduction scheme for polymer semiconductors is developed to rapidly compute intra‐chain hole mobility from monomer sequence within choices of quantum dynamics method. The procedure is illustrated considering 28 realistic polymers, and the maximum plausible improvement in polymer mobility within realistic range of microscopic parameters as well as correlation between charge localization characteristics and mobility are established.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Semiconductors are widely used in electron devices. With the development of wearable soft-electron devices, conventional inorganic semiconductors are unable to meet the demand because of their high ...rigidity and high cost. Thus, scientists construct organic semiconductors with high charge mobility, low cost, eco-friendly, stretchable, etc. Due to the excellent performance of stretchable organic semiconductors, they can be widely used as wearable soft-electron devices, such as stretchable organic field-effect transistors (OFETs), organic solar cells (OSCs), etc. Contains flexible display devices and flexible power sources, which are of great interest for applications of future electron devices. However, there are still some challenges that need to be solved. Commonly, enhancing the stretchability may cause the degradation of charge mobility, because of the destruction of the conjugated system. Currently, scientists find that hydrogen bonding can enhance the stretchability of organic semiconductors with high charge mobility. Thus in this review, based on the structure and design strategies of hydrogen bonding, various hydrogen bonding induced stretchable organic semiconductors are introduced. In addition, the applications of the hydrogen bonding induced stretchable organic semiconductors are reviewed. Finally, the stretchable organic semiconductors design concept and potential evolution trends are discussed. The final goal is to outline a theoretical scaffold for the design of high-performance wearable soft-electron devices, which can also further advance the development of stretchable organic semiconductors for applications.
•α-6T as an electron donor is firstly introduced to fabricate a low-cost TPSC.•Obvious improvement of PCE with an increase of JSC and FF is achieved.•Performance improvement is mainly due to the FRET ...and enhanced charge mobility.•α-6T decreases the resistance and provide more pathways for charge transportation.•α-6T can also modulate the morphology of the active layer.
In this study, the enhanced performance of a conventional bulk heterojunction (BHJ) system based on poly({4,8-bis(2-ethylhexyl)oxybenzo1,2-b:4,5-b′dithiophene-2,6-diyl}{3-fluoro-2-(2-ethylhexyl)carbonylthieno3,4-bthiophenediyl}) (PTB7):6,6-phenyl C71-butyric acid methyl ester (PC71BM) is realized by adding a high charge mobility and low-cost small-molecular material of alpha-hexathienyl (α-6T) as an electron donor. Both the short circuit current (JSC) and fill factor (FF) are facilitated by adding 2 wt% α-6T to form a ternary system, resulting in a 22.2% improvement of power conversion efficiency (PCE) compared with the control binary device. The state-of-art BHJ layer was characterized by UV–Vis absorption, steady-state photoluminescence, space-charge-limited current, atomic force microscopy, and impedance spectra, and the enhanced device performance is mainly attributed to the Förster resonance energy transfer effect from α-6T to PTB7 and the increased charge mobility. The result also showed that the blend morphology can be modulated by the introduction of α-6T electron donor. Moreover, the incorporation of α-6T can contribute to the formation of more potential pathways for charge transportation in the active layer, and decrease the resistance of device.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Organic semiconductors are the focus of numerous studies; they are used in electronic devices. Modern research involves the production of neuromorphic organic materials, including those based on ...liquid crystal materials. The purpose of this work involves the theoretical modeling of molecules (the "core with branches" type) to construct a discotic mesophase capable of performing the functions of a neuromorphic material. For this purpose, the conductivity of crystal porphine, which can act as the nucleus of a molecule of the "core with branches" type, was investigated. The Marcus theory charge mobility values for the hole and electron were 0.148 and 0.088 cm
/V·s, respectively (the MOO method for calculating transfer integrals), and 0.561 and 0.160 cm
/V·s (DIPRO method). Based on TD-HF (HF-3c level of theory) calculations, possible structures of molecules for the formation of a discotic mesophase are proposed.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We have investigated the electronic structures and carrier mobility of two dimensional (2D) metal coordination polyporphyrin (PP) sheets using density functional theory combined with Boltzmann ...transport method with relaxation time approximation. Two families of metal coordination atoms are studied: 1) 3d-transition metals (TM) Fe and Co; and 2) nonferrous metals (NM) Li and Zn. It is shown that 2H-PP, 2Li-PP and Zn-PP are direct gap semiconductors, while Fe-PP and Co-PP are spin-splitting and behave like half-metallic. Moreover, the charge mobilities have been carried out under periodic boundary conditions for infinite 2D PP systems, and found that the electron mobility is higher than that of the hole's, which indicating the n-type semiconducting characteristic. Furthermore, we also found the hole mobility in all systems show anisotropy in-plane.
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•Charge mobility and half-metallicity in two dimensional metal coordination PP sheets.•All 2D metal coordination PP sheets show n-type semiconducting.•The hole mobility in all systems show anisotropy in-plane.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A tunneling‐enabled hopping mechanism is proposed, providing a pratical tool to quantitatively assess charge mobility in organic semiconductors. The paradoxical phenomena in TIPS‐pentacene is well ...explained in that the optical probe indicates localized charges while transport measurements show bands of charge.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A computationally simple yet predictive multi-scale simulation scheme is introduced to estimate zero-field charge mobilities for amorphous OSC materials. A percolating charge model is utilized to ...describe inhomogeneity of hopping trajectories of carriers in amorphous media. The prediction scheme is composed of the following stages: quantum chemical calculation of Marcus inner sphere reorganization energies, molecular dynamics simulations of the amorphous condensed phase bulk structure, automated quantum chemical calculations of the electronic coupling for dimer pairs in the amorphous solid, and calculation of the Marcus theory charge hopping rates and an estimated bulk mobility using the Einstein relation, corrected for the inhomogeneous hopping network of the solid. Comparisons with independent experimental measurements of hole mobility for ten OSC compounds show that this approach gives good correlation between predictions and measurements suitable for ranking systems, and useful quantitative agreement. This low-cost model with minimal complexity is well-suited for incorporation into a virtual materials discovery framework for advanced OSC solutions.
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•A method for estimating charge mobility of amorphous molecular solids is proposed.•The model tempers simple diffusion with a correction based on hopping connectivity.•The approach is well suited for initial screening of organic semiconductors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Temperature can change the charge injection and migration characteristics in the liquid, affecting the insulation performance. First, the influence of temperature on the permittivity and Kerr ...constant of the liquid dielectric is studied. Also, the results prove that the permittivity and Kerr constant of propylene carbonate (PC) decrease with the increase of temperature. Moreover, to explore the influence of temperature on the insulation performance of propylene carbonate, we build a temperature-controllable breakdown test platform under voltage impulse, and the breakdown voltage of PC increases slightly with the increase in temperature. Based on the electrooptic effect, an optical platform is built to measure the electric field under the switching overvoltage. In addition, the space charge distribution is calculated, and the results indicated that the temperature in the range of 10 °C-40 °C is negatively correlated with the net space charge injection. Finally, the temperature effect on the rate of change and mobility of the space charges is explored.
Three new molecular A-π-D-π-A type donors, P1, P2 and P3, comprising an alkylthiothienyl substituted porphyrin electron donor core (D) and two 3-ethylrhodanine electron acceptor moieties (A) ...connected peripherally to the porphyrin core via respectively a monomeric, dimeric or trimeric phenylethynyl π-linkage, are synthesized and studied for their optoelectronic, charge transport, and photovoltaic properties. The hole mobilities of their blend films with PC71BM follow the order of P3> P2 > P1 in hole-only device. When used as electron donors with fullerene acceptor, PC71BM, in conventional bulk heterojunction organic solar cells, the optimal device with P1 donors shows a lower FF, but an intensity stronger and broader EQE, the highest JSC and VOC. As a whole, the PCEs of their optimal devices follow the order of P1> P2 > P3, corresponding to 8.61%, 8.20% and 7.82%, respectively. These results clearly demonstrate the decisive influence of π–linkage length over photovoltaic performance, and that the shorter the π–linkage length the better the photovoltaic performance.
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•Three new A-π-D-π-A donors with mono, di and trimeric phenylethynyl π-linkages are synthesized.•The π–linkages influence their optoelectronic, charge transport, and photovoltaic properties.•The donor with trimeric phenylethynyl π-linkages shows the highest hole mobility.•The donor with monomeric phenylethynyl π-linkage performs the best in photovoltaics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
