Unifying Energetic Disorder from Charge Transport and Band Bending in Organic Semiconductors

Unifying Energetic Disorder from Charge Transport and Band Bending in Organic Semiconductors

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 r...

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Bibliographic Details
Published in:Advanced functional materials Vol. 29; no. 20
Main Authors: 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
Format: Journal Article
Language:English
Published: Hoboken Wiley Subscription Services, Inc 16-05-2019
Wiley
Wiley Blackwell (John Wiley & Sons)
Series:Advanced Functional Materials
Subjects:
band bending
Carrier mobility
characterization techniques
Charge transport
Chemical Sciences
crystallinity
Current carriers
Density of states
density‐of‐state widths
energetic disorder
Inorganic chemistry
Materials science
Morphology
NMR spectroscopy
organic conjugated polymers
Organic semiconductors
Polymers
solid‐state NMR
Thin films
Transport properties
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Summary: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.
Bibliography:DE‐AC02‐05CH11231
USDOE
ISSN:1616-301X
1616-3028
DOI:10.1002/adfm.201901109