TY - JOUR
T1 - The influence of film morphology in high-mobility small-molecule: Polymer blend organic transistors
T2 - Polymer blend organic transistors
AU - Smith, Jeremy
AU - Hamilton, Richard
AU - Qi, Yabing
AU - Kahn, Antoine
AU - Bradley, Donal D.C.
AU - Heeney, Martin
AU - McCulloch, Iain
AU - Anthopoulos, Thomas D.
N1 - Generated from Scopus record by KAUST IRTS on 2023-02-14
PY - 2010/7/23
Y1 - 2010/7/23
N2 - Organic field-effect transistors (OFETs) based upon blends of small molecular semiconductors and polymers show promise for high performance organic electronics applications. Here the charge transport characteristics of high mobility p-channel orpnic transistors based on 2,8-difluoro-5,11- bis(triethylsilylethynyl) anthradithiophene:poly(triarylamine) blend films are investigated. By simple alteration of the film processing conditions two distinct film microstructures can be obtained: one characterized by small spherulitic grains (SG) and one by large grains (LC). Charge transport measurements reveal thermally activated hole transport in both SC and LG film microstructures with two distinct temperature regimes. For temperatures >115 K, gate voltage dependent activation energies (EA) in the range of 25-60 meV are derived. At temperatures <115 K, the activation energies are smaller and typically in the range 5-30 meV. For both film microstructures hole transport appears to be dominated by trapping at the grain boundaries. Estimates of the trap densities suggests that LG films with fewer grain boundaries are characterized by a reduced number of traps that are less energetically disordered but deeper in energy than for small SG films. The effects of source and drain electrode treatment with self-assembled monolayers (SAMs) on current injection is also investigated. Fluorinated thiol SAMs were found to alter the work function of gold electrodes by up to ∼1 eV leading to a lower contact resistance. However, charge transport analysis suggests that electrode work function is not the only parameter to consider for efficient charge injection.
AB - Organic field-effect transistors (OFETs) based upon blends of small molecular semiconductors and polymers show promise for high performance organic electronics applications. Here the charge transport characteristics of high mobility p-channel orpnic transistors based on 2,8-difluoro-5,11- bis(triethylsilylethynyl) anthradithiophene:poly(triarylamine) blend films are investigated. By simple alteration of the film processing conditions two distinct film microstructures can be obtained: one characterized by small spherulitic grains (SG) and one by large grains (LC). Charge transport measurements reveal thermally activated hole transport in both SC and LG film microstructures with two distinct temperature regimes. For temperatures >115 K, gate voltage dependent activation energies (EA) in the range of 25-60 meV are derived. At temperatures <115 K, the activation energies are smaller and typically in the range 5-30 meV. For both film microstructures hole transport appears to be dominated by trapping at the grain boundaries. Estimates of the trap densities suggests that LG films with fewer grain boundaries are characterized by a reduced number of traps that are less energetically disordered but deeper in energy than for small SG films. The effects of source and drain electrode treatment with self-assembled monolayers (SAMs) on current injection is also investigated. Fluorinated thiol SAMs were found to alter the work function of gold electrodes by up to ∼1 eV leading to a lower contact resistance. However, charge transport analysis suggests that electrode work function is not the only parameter to consider for efficient charge injection.
UR - https://onlinelibrary.wiley.com/doi/10.1002/adfm.201000427
UR - http://www.scopus.com/inward/record.url?scp=77955411861&partnerID=8YFLogxK
U2 - 10.1002/adfm.201000427
DO - 10.1002/adfm.201000427
M3 - Article
AN - SCOPUS:77955411861
SN - 1616-301X
VL - 20
SP - 2330
EP - 2337
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 14
ER -