The dark current-voltage characteristics of poly (3-hexylthiophene) (P3HT)/$n$ -type crystalline silicon solar cells were analyzed using an electrical equivalent circuit. We found that without illumination transport occurs due to hopping between localized states at the P3HT/silicon interface not only at low voltages, through multitunneling capture emission, but also at medium voltages, through tunneling-enhanced recombination. At high voltages the current is limited by series resistance and space-charge limited mechanisms. At low reverse voltages the current is limited by shunt resistance. From the temperature dependence of the equivalent circuit’s fitting parameters, we were able to estimate some physical parameters of the P3HT layer, namely the electron affinity, the charge carrier concentration and the characteristic temperature of the exponential trap distribution. The extracted P3HT values are in good agreement with previously reported values obtained using different methods but our approach takes into account that the P3HT layer is in a solar cell.

The mechanisms limiting the dark current in pentacene (Pc)/${\text{C}}_{60}$ solar cell were determined using the temperature dependence of the current-density-voltage characteristics. Our analysis allowed us to calculate the effective barrier height for electrons and holes at the interface. We then determined the built-in potential of the heterojunction and the effective doping concentration of the active layers, using capacitance-voltage characteristics. These physical parameters were used to simulate a band-energy diagram for a Pc/${\text{C}}_{60}$ solar cell in equilibrium. Finally, we determined a relation between the effective barrier height and the built-in potential.

The authors present an analytical and continuous model for the total charges at the gate, drain and source electrodes for organic thin-film transistors (OTFTs), from which analytical expressions of the total capacitances are obtained. Under the quasi-static approximation, the model parameters are extracted using the previously developed unified model and parameter extraction method (UMEM). The capacitance model is valid above threshold voltage. It guarantees continuity of the expressions for the capacitance at the transition between linear and saturation regimes, as well as takes into account the overlap capacitance. Comparisons between modelled and experimental C_GG values are shown.

Bottom-contact organic thin-film transistors with active layers made of n-type small-molecule perylene diimide Polyera ActivinkTM N1400 were fabricated and were compared with those of 6,13-bis (triisopropylsilylethinyl)pentacene and poly(triarylamine) (PTAA). For the three devices, the mobility values and the distribution of the density of states (DOS) were estimated from current-voltage measurements. The mobility value of the N1400 samples increases up to four orders of magnitude within the measured voltage range, reaching the PTAA mobility values at high gate voltages. Finally, we analyze the effect of the distribution of the DOS on the mobility by studying the free-charge sheet concentration.