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Pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) have been used as organic semiconductors for the fabrication of p-type and n-type organic thin-film transistors (OTFTs). Both types of semi-conductors are well-established and demonstrate good performance in singledevices, but few competitive results have been reported in complementary circuits. In this manuscript, we show the fabrication, electrical characterization and simulation of an organic complementary inverter using pentaceneand PTCDI-C13 as active semiconductors. Simulation was done using a model with physical aspects. The fitting of the parameters of the OTFT model is performed using an optimized parameter extraction technique which is using fuzzy logic to adjust the parameters to its optimal value. We also report good fitting of p-type and n-type parameters for the OTFT model and good results for DC transfer characteristics of the organic complementary inverter. In order to account for the presence of important parasitic elements, we show that the DC characteristics are best simulated using a transient analysis, instead of a DC.

Shallow traps play a significant role in influencing charge dynamics through organic molecular thin films, such as pentacene. Sandwich cells of pentacene capped by gold electrodes are an excellent specimen to study the nature of underlying charge dynamics. In this paper, self-consistent numerical simulation of I–V characteristics is performed at various temperatures. The results have revealed negative value of Poole Frenkel coefficient. The location of trap energy level is found to be located at 0.24 eV above the highest occupied molecular orbit (HOMO) level of pentacene. Other physical parameters related to trap levels, such as density of states due to traps and effective carrier density due to traps, have also been estimated in this study.

The organic thin film transistor (OTFT) on flexible substrate electroplated electrodes has many advantages as in the fabrication of low cost sensors, e-paper, smart cards, and flexible displays. In this study, we simulated the mechanical and electrical characteristics of the OTFT with various voltage conditions by using COMSOL. The model consisting of a channel, source and drain was employed to investigate the temperature distribution and thermal stress concentration. The channel length is 40 µm and the voltage ranged between -20V and -40V. The OTFT was fabricated using pentacene as a semiconducting layer and electroplated Ni as a gate electrode. Mechanical properties of the fabricated OTFT were characterized by thermal stress which was predicted with the result of stress distribution.

In order to investigate the feasibility of gating organic field-effect transistors (OFETs) using a photosensitive photoresist material, pentacene-based OFETs were fabricated on indium tin oxide (ITO) glass. The gate dielectric was found to be easily patterned by spin coating and UV exposure, and has an excellent surface roughness of 0.22 nm and good insulating properties, resulting in a low leakage current (49 nA at 2 MV/cm) at a dielectric thickness of 290 nm. The OFET with photopatterned gate dielectric exhibited good electric characteristics, including a high field-effect mobility of 0.15 cm²/Vs, a threshold voltage of -9.9 V, and on/off current ratio of ~10⁴. The high matching of surface free energy between the gate dielectric and pentacene is proved to be contributed to the good performance of the device.

A short channel organic field effect transistors (OFET) based on Pentacene, having channel length in the range of sub-micrometer, has been numerically modelled for low values of drain voltage. The output characteristics show a nonlinear concave increase of drain current for all values of gate voltages. This anomalous current-voltage behavior, which resembles sub-threshold characteristics of silicon FETs, shows a good match with earlier experimental reports on OFET at low drain voltages. The sub-threshold-like characteristics has been interpreted in light of thermionic-emission model because of the presence of hole injection barrier at drain (gold)/Pentacene interface. The associated analysis has facilitated to obtain a significant parameter, effective channel thickness $(t_{\mathrm{\text{eff}}})$, for the first time in case of OFETs. It came out to be roughly 4 nm and 8 nm for experimental devices of poly(3-hexylthiophene-2,5-diyl) and Pentacene, respectively, while the numerically modelled device yielded a value of about 60 nm. Increase of $t_{\mathrm{\text{eff}}}$ with transverse gate electric field is also observed. Physical explanation of the observations is also presented.

The isomeric effects on the adsorption geometry of di-halobenzene (C₆H₄X₂; X = F, Cl, Br, I) and pentacene (C₂₂H₁₄) on the idealized non-interacting substrate are analyzed both qualitatively and quantitatively by means of Monte Carlo simulations. The shape of pentacene isomers and the relative positions of halogen atoms in di-halobenzene may be important in determination of the favored adsorption geometry, contributing to the thermodynamic and chemical factors affecting the determination of the adsorbate geometry for these system. These simple methods may be applied to any planar molecules to quantify the contributions to the adsorption geometry that arises solely from the topological or geometrical isomeric differences in the molecules of interest.

An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO₂ as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (μ_FET), values, threshold voltages (V_T) and on/off current ratios (I_on/I_off). OTFTs exhibited saturation at the order of μ_FET of 3.92 cm²/Vs and 0.86 cm²/Vs at different thicknesses. I_on/I_off and V_T are also thickness dependent. I_on/I_off is 1 × 10³, 2 × 10² and V_T is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous.

The electronic conductance characteristics of a pentacene molecular tap has been investigated theoretically by a Green's function approach based on an empirical tight-binding theory in which only one π orbital electron per carbon atom is considered. The quantum transmission probability for electrons through the pentacene tap from an input to three other outputs is obtained. A strong dependence of the transmission probability on the incident electron energy and the molecular energy levels is evident for all three input–output combinations. The electronic current distributions inside the pentacene tap are calculated by a current density method based on the Fisher–Lee formula for two electron energies (E = ± 0.68 and ±1.31 eV) at which the transmission spectra peaks. The current distributions are in good agreement with the Kirchhoff quantum current momentum conservation law.

The synthesis of a ruthenium(II) tetramer (Ru(L${}_{pc}$)${}_4$Cl${}_2)$ bearing pyridyl pentacene-based ligands and its corresponding model complex lacking pentacene moieties (Ru(L${}_{ref}$)${}_4$Cl${}_2)$ is presented. The formation of these tetramers is corroborated by ¹H, ${}^{13}$C NMR, and IR spectroscopies, as well as X-ray crystallography and mass spectrometry. Photophysical properties of the tetramers are probed by steady-state and time-resolved transient absorption spectroscopy. Steady-state absorption and fluorescence assays suggest weak ground-state interactions between the pentacene moieties of Ru(L${}_{pc}$)${}_4$Cl${}_2$ and sizeable metal-to-ligand interactions, which are ruthenium-to-pentacene based. Time-resolved transient absorption measurements reveal an ultrafast singlet-to-triplet transition that occurs on the femtosecond timescale and that yields vibrationally hot and solvent unrelaxed triplet excited states. After relaxation, these triplet excited states deactivate back to the ground state in less than 3 $\mu$s. These observations lead us to conclude that intersystem crossing outperforms photophysical processes such as singlet fission.

We propose a "field-induced polymorphous disorder" model to explain bias-stress instability in molecular organic thin-film transistors, based on the experimental results showing the strong correlation between the micro-structural change in semiconductor layer composed of penrtacene molecules and the threshold voltage (Vth) shift due to electron trapping in a reversible manner under the successive bias-stress, thermal annealing, and light irradiation.