RESUMEN
We prepared an indium-free metal oxide thin-film transistor (TFT) using a double-active-layers structure at room temperature. We changed the growth sequence of Al-doped zinc oxide (AZO) and zinc oxide (ZnO) double-active-layers on Si/SiO2 substrates by magnetron sputtering deposition to regulate the field-effect performance of TFTs. According to the analysis of field-effect properties before and after annealing in different atmospheres, the performance of TFT devices with ZnO/AZO/SiO2/Si double-active-layers was obviously better than that with single AZO or ZnO active layer and inverted AZO/ZnO/SiO2/Si double-active-layers in the device structure. The active layer with higher carrier concentration (AZO in this case) was closer to the dielectric layer, which was more favorable for carrier regulation in TFT devices. In addition, the annealed device had a lower on/off ratio (Ion/Ioff), easier-to-reach on-state, and higher mobility. Furthermore, the performance of the devices annealed under vacuum condition was obviously better than that annealed under air atmosphere. The Ion/Ioff could reach 6.8 × 105 and the threshold voltage was only 2.9 V.
RESUMEN
Double-walled carbon nanotubes (DWNTs) have shown potential as promising alternatives to conventional transparent electrodes owing to their solution processability as well as high conductivity and transparency. However, their DC to optical conductivity ratio is limited by the surrounding surfactants that prevent the p-doping of the DWNTs. To maximize the doping effectiveness, the surfactants are removed from the DWNTs, with negligible damage to the nanotubes, by calcination in an Ar atmosphere. The effective removal of the surfactants is characterized by various analyses, and the results show that the optimal calcination temperature is 400 °C. The conductivity of the DWNTs films improves when doped by triflic acid. While the conductivity increase of the surfactants-wrapped DWNT films is 31.9%, the conductivity increase of the surfactants-removed DWNT is found to be 59.7%. Using the surfactants-removed, p-doped, solution-processed transparent electrodes, inverted-type perovskite solar cells are fabricated, resulting in a power conversion efficiency of 17.7% without hysteresis. This work advances the application of DWNTs in transparent conductors, as the efficiency obtained is the highest value achieved to date for carbon nanotube electrode-based perovskite solar cells and solution-processable transparent electrode-based solar cells.
RESUMEN
In this study, for high-performance indium-free metal oxide channel layer, we synthesize Zn-Sn-O (ZTO) precursor solutions in which formamide is incorporated as an additive for catalyzing the subsequent sol-gel reactions and the evolution of chemical structure. It is revealed that the formamide plays a critical chemical role in evolving a chemical structure with more oxygen-deficient oxide lattice and with less hydroxide, allowing for high field-effect mobility over 7 cm(2)/V·s. Furthermore, it is for the first time demonstrated that electrically active metal-oxide films can be patterned, using an air-brush printing technique, by directly depositing formamide-mediated ZTO-precursor solutions in patterned geometries.