Hall Effect in Polycrystalline Organic Semiconductors: The Effect of Grain Boundaries

• DOI: 10.1002/adfm.201903617
• Publication Date: 2019-07-11T13:44:08Z
• Authors: Hyun Ho Choi; Alexandra F. Pate...; Michael A. Fusella; Julianna Panidi; Olga Solomeshch; Nir Tessler; Martin Heeney; Kilwon Cho; Thomas D. Anthopo...; Barry P. Rand; Vitaly Podzorov
• Keywords: Organic semiconductor; Rubrene; Electron Mobility

Abstract Highly crystalline thin films in organic semiconductors are important for applications high‐performance optoelectronics. Here, the effect of grain boundaries on Hall and charge transport properties transistors based two exemplary benchmark systems is elucidated: (1) solution‐processed blends 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C 8 ‐BTBT) small molecule indacenodithiophene‐benzothiadiazole 16 IDT‐BT) conjugated polymer, (2) large‐area vacuum evaporated polycrystalline rubrene 42 H 28 ). It discovered that, despite high field‐effect mobilities up to 6 cm 2 V −1 s evidence a delocalized band‐like transport, systematically significantly underdeveloped, with carrier coherence factor α < 1 (i.e., yields an underestimated mobility overestimated density). A model capacitively charged explaining this unusual behavior described. This work advances understanding magneto‐transport semiconductor films.