Role of the electronically-active amorphous state in low-temperature processed In2O3 thin-film transistors

Improvement of Open-Circuit Voltage Deficit via Pre-Treated NH4 + Ion Modification of Interface between SnO2 and Perovskite Solar Cells

Passivation is a popular method to increase power conversion efficiency (PCE), reduce hysteresis related to surface traps and defects, and adjust mismatched energy levels. In this paper, an approach is reported using ammonium chloride (AC) to enhance passivation effects by controlling chlorine (Cl) and ammonium ions (NH₄ ⁺ ) on the front and back side of tin oxides (SnO₂ ). AC pre-treatment is applied to indium tin-oxide (ITO) prior to SnO₂ deposition to advance the passivation approaches and compare the completely separated NH₄ ⁺ and Cl passivation effects, and sole NH₄ ⁺ is successfully isolated on the SnO₂ surface, the counterpart of AC-post-treatment, generating ammonia (NH₃ ) and Cl. It is demonstrated that multifunctional healing effects of NH₄ ⁺ are ascribed from AC-pre-treatment being the basis of SnO₂ crystallization and adjusting bifacial interface energy levels at ITO/SnO₂ and SnO₂ /perovskite to enhance photo-carrier transport. As calculated by density functional theory, how the change of the passivation agent from Cl to NH₄ ⁺ more effectively suppresses non-radiative recombination ascribed to hydrated SnO₂ surface defects is explained. Consequently, enhancement of photo-carrier transport significantly improves a superior open-circuit voltage of 1.180 V and suppresses the hysteresis, which leads to the PCE of 22.25% in an AC-pre-treated device 3.000% higher than AC-post-treated devices.

Recent Advances in Metal−Oxide Thin−Film Transistors: Flexible/Stretchable Devices, Integrated Circuits, Biosensors and Neuromorphic Applications

Thin−film transistors using metal oxides have been investigated extensively because of their high transparency, large area, and mass production of metal oxide semiconductors. Compatibility with conventional semiconductor processes, such as photolithography of the metal oxide offers the possibility to develop integrated circuits on a larger scale. In addition, combinations with other materials have enabled the development of sensor applications or neuromorphic devices in recent years. Here, this paper provides a timely overview of metal−oxide−based thin−film transistors focusing on emerging applications, including flexible/stretchable devices, integrated circuits, biosensors, and neuromorphic devices. This overview also revisits recent efforts on metal oxide−based thin−film transistors developed with high compatibility for integration to newly reported applications.