Influence of Semiconductor Thickness and Molecular Weight on the Charge Transport of a Naphthalenediimide-Based Copolymer in Thin-Film Transistors.
ACS Appl Mater Interfaces
; 7(23): 12478-87, 2015 Jun 17.
Article
en En
| MEDLINE
| ID: mdl-25781339
ABSTRACT
The N-type semiconducting polymer, P(NDI2OD-T2), with different molecular weights (MW=23, 72, and 250 kg/mol) was used for the fabrication of field-effect transistors (FETs) with different semiconductor layer thicknesses. FETs with semiconductor layer thicknesses from â¼15 to 50 nm exhibit similar electron mobilities (µ's) of 0.2-0.45 cm2 V(-1) s(-1). Reduction of the active film thickness led to decreased µ values; however, FETs with â¼2 and â¼5 nm thick P(NDI2OD-T2) films still exhibit substantial µ's of 0.01-0.02 and â¼10(-4) cm2 V(-1) s(-1), respectively. Interestingly, the lowest molecular weight sample (P-23, MW≈23 kg/mol, polydispersity index (PDI)=1.9) exhibited higher µ than the highest molecular weight sample (P-250, MW≈250 kg/mol, PDI=2.3) measured for thicker devices (15-50 nm). This is rather unusual behavior because typically charge carrier mobility increases with MW where improved grain-to-grain connectivity usually enhances transport events. We attribute this result to the high crystallinity of the lowest MW sample, as confirmed by differential scanning calorimetry and X-ray diffraction studies, which may (over)compensate for other effects.
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1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
ACS Appl Mater Interfaces
Asunto de la revista:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Alemania