TY - JOUR
T1 - From Amorphous to Polycrystalline Rubrene
T2 - Charge Transport in Organic Semiconductors Paralleled with Silicon
AU - Euvrard, Julie
AU - Gunawan, Oki
AU - Kahn, Antoine
AU - Rand, Barry P.
N1 - Funding Information:
J.E. acknowledges the support of a Distinguished Postdoctoral Fellowship from the Andlinger Center for Energy and the Environment at Princeton University. The authors acknowledge a Princeton University School of Engineering and Applied Science Project X award, and the IBM Research Exploratory Science program. The authors acknowledge the use of Princeton's Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials (PCCM), a National Science Foundation (NSF)-MRSEC program (DMR-2011750).
Funding Information:
J.E. acknowledges the support of a Distinguished Postdoctoral Fellowship from the Andlinger Center for Energy and the Environment at Princeton University. The authors acknowledge a Princeton University School of Engineering and Applied Science Project X award, and the IBM Research Exploratory Science program. The authors acknowledge the use of Princeton's Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials (PCCM), a National Science Foundation (NSF)‐MRSEC program (DMR‐2011750).
Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2022/12/2
Y1 - 2022/12/2
N2 - While progress has been made in the design of organic semiconductors (OSCs) with improved transport properties, the understanding of the mechanisms involved is still limited, hindering further development. In this study, the interplay between structural order and transport considering one single OSC, analogous to past research on silicon is investigated. Rubrene (C42H28) is selected as it spans transport mechanisms from thermally activated hopping in its amorphous form to band-like in highly ordered crystals in the orthorhombic polymorph. Transport characterizations including variable temperature conductivity, advanced Hall effect, and magnetoresistance measurements are performed on rubrene films with varying levels of order (polycrystalline vs amorphous), crystal phase (orthorhombic vs triclinic), and morphologies (platelet-like vs spherulitic grains). A conductivity tuning range over four orders of magnitude between polycrystalline (platelet-like) orthorhombic and amorphous films is reported. As observed in silicon, transport in polycrystalline orthorhombic rubrene is limited by energy barriers at grain boundaries. Additionally, a gradual transition from predominantly band-like to predominantly hopping transport with increasing disorder, reminiscent of observations in silicon is shown. Nevertheless, OSCs differ from covalently bonded silicon by their weak intermolecular interaction. This study highlights that molecular packing must be optimized in OSCs to favor advantageous π-orbital overlap and optimized transport properties.
AB - While progress has been made in the design of organic semiconductors (OSCs) with improved transport properties, the understanding of the mechanisms involved is still limited, hindering further development. In this study, the interplay between structural order and transport considering one single OSC, analogous to past research on silicon is investigated. Rubrene (C42H28) is selected as it spans transport mechanisms from thermally activated hopping in its amorphous form to band-like in highly ordered crystals in the orthorhombic polymorph. Transport characterizations including variable temperature conductivity, advanced Hall effect, and magnetoresistance measurements are performed on rubrene films with varying levels of order (polycrystalline vs amorphous), crystal phase (orthorhombic vs triclinic), and morphologies (platelet-like vs spherulitic grains). A conductivity tuning range over four orders of magnitude between polycrystalline (platelet-like) orthorhombic and amorphous films is reported. As observed in silicon, transport in polycrystalline orthorhombic rubrene is limited by energy barriers at grain boundaries. Additionally, a gradual transition from predominantly band-like to predominantly hopping transport with increasing disorder, reminiscent of observations in silicon is shown. Nevertheless, OSCs differ from covalently bonded silicon by their weak intermolecular interaction. This study highlights that molecular packing must be optimized in OSCs to favor advantageous π-orbital overlap and optimized transport properties.
KW - Hall effect
KW - band-like charge transports
KW - charge transport
KW - hopping charge transports
KW - magnetoresistance
KW - organic semiconductors
KW - polycrystalline films
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U2 - 10.1002/adfm.202206438
DO - 10.1002/adfm.202206438
M3 - Article
AN - SCOPUS:85139392675
SN - 1616-301X
VL - 32
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 49
M1 - 2206438
ER -