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Hall Effect in Polycrystalline Organic Semiconductors: The Effect of Grain Boundaries
Author(s) -
Choi Hyun Ho,
Paterson Alexandra F.,
Fusella Michael A.,
Panidi Julianna,
Solomeshch Olga,
Tessler Nir,
Heeney Martin,
Cho Kilwon,
Anthopoulos Thomas D.,
Rand Barry P.,
Podzorov Vitaly
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201903617
Subject(s) - materials science , organic semiconductor , rubrene , grain boundary , crystallite , delocalized electron , thin film , semiconductor , electron mobility , hall effect , optoelectronics , thin film transistor , field effect transistor , condensed matter physics , transistor , nanotechnology , composite material , organic chemistry , electrical resistivity and conductivity , electrical engineering , chemistry , metallurgy , layer (electronics) , microstructure , engineering , voltage , physics
Highly crystalline thin films in organic semiconductors are important for applications in high‐performance organic optoelectronics. Here, the effect of grain boundaries on the Hall effect and charge transport properties of organic transistors based on two exemplary benchmark systems is elucidated: (1) solution‐processed blends of 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C 8 ‐BTBT) small molecule and indacenodithiophene‐benzothiadiazole (C 16 IDT‐BT) conjugated polymer, and (2) large‐area vacuum evaporated polycrystalline thin films of rubrene (C 42 H 28 ). It is discovered that, despite the high field‐effect mobilities of up to 6 cm 2 V −1 s −1 and the evidence of a delocalized band‐like charge transport, the Hall effect in polycrystalline organic transistors is systematically and significantly underdeveloped, with the carrier coherence factor α < 1 (i.e., yields an underestimated Hall mobility and an overestimated carrier density). A model based on capacitively charged grain boundaries explaining this unusual behavior is described. This work significantly advances the understanding of magneto‐transport properties of organic semiconductor thin films.