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  • Unifying Energetic Disorder...
    Karki, Akchheta; Wetzelaer, Gert‐Jan A. H.; Reddy, Gollapalli Narayana Manjunatha; Nádaždy, Vojtech; Seifrid, Martin; Schauer, Franz; Bazan, Guillermo C.; Chmelka, Bradley F.; Blom, Paul W. M.; Nguyen, Thuc‐Quyen

    Advanced functional materials, May 16, 2019, Letnik: 29, Številka: 20
    Journal Article

    Characterizing the density of states (DOS) width accurately is critical in understanding the charge‐transport properties of organic semiconducting materials as broader DOS distributions lead to an inferior transport. From a morphological standpoint, the relative densities of ordered and disordered regions are known to affect charge‐transport properties in films; however, a comparison between molecular structures showing quantifiable ordered and disordered regions at an atomic level and its impact on DOS widths and charge‐transport properties has yet to be made. In this work, for the first time, the DOS distribution widths of two model conjugated polymer systems are characterized using three different techniques. A quantitative correlation between energetic disorder from band‐bending measurements and charge transport is established, providing direct experimental evidence that charge‐carrier mobility in disordered materials is compromised due to the relaxation of carriers into the tail states of the DOS. Distinction and quantification of ordered and disordered regions of thin films at an atomic level is achieved using solid‐state NMR spectroscopy. An ability to compare solid‐state film morphologies of organic semiconducting polymers to energetic disorder, and in turn charge transport, can provide useful guidelines for applications of organic conjugated polymers in pertinent devices. A quantitative correlation between energetic disorder from charge transport and band bending measurements is established for two organic semiconducting polymers providing direct experimental evidence that charge carrier mobility is compromised due to the relaxation of charge carriers into the tail states of the density‐of‐states distribution. Ordered and disordered regions of polymer films were distinguished and quantified at an atomic‐scale.