Effect of [6,6]-Phenyl-C61 butyric acid methyl ester (PCBM) agglomerated nanostructure on device performance in organic thin-film transistors

Abstract

The influence of [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM) agglomerated nanostructure on device performance of pentacene-based organic thin-film transistors (OTFTs) were reported. The presence of PCBM layers on a SiO₂ gate dielectric resulted in a good electrical characteristics of pentacene-based OTFTs, including a relatively high mobility (μ = 0.95-2.2 cm² V^-1 s^-1), low threshold voltages (V_th = -1.1 - -5.4 V), a high on/off current ratio (I_on/I_off = 10⁴), and a high value of subthreshold slope (SS = 6.5 V/decade). The surface topography studies reveal that the PCBM nanostructure could favor the reduction of grain boundaries, which resulted in a better transistor performance of pentacene-based OTFTs. The influence of PCBM on the molecular microstructure of pentacene thin films elucidates a reasonable explanation for higher performance on OTFTs.