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An all-inorganic heterojunction phototransistor using a highly stable perovskite (CsPbIxBr3−x) and amorphous In–Ga–Zn–O (IGZO) double-layer is introduced to enhance the sensing performance of optoelectronic devices and to expand their detecting range from the ultraviolet to the visible light region. Despite the high-performance photoelectric properties of CsPbI3 perovskites retaining the α-phase, actual applications of the perovskite film are considerably hindered by the phase instability under ambient conditions. Here, in order to improve the long-term stability of the α-phase perovskite, we propose a multiple anion strategy in the perovskite structure. The developed CsPbIxBr3−x film is applied with bi-anion IxBr3−x instead of I3 by adding CsBr and PbBr2 in the CsPbI3 precursor solution. Using the optimized CsPbIxBr3−x film with 12 wt% of the additives CsBr and PbBr2 in the CsPbI3 precursor solution, we demonstrate an all-inorganic visible light detector based on a heterojunction phototransistor with a p++-Si/SiO2/IGZO/CsPbIxBr3−x/Ti–Al–Ti structure, in which IGZO and CsPbIxBr3−x are used as a charge transport layer and a light absorption layer, respectively. The phototransistor exhibits a responsivity of 26.48 A W−1, a detectivity of 8.42 × 1014 Jones, and an external quantum efficiency of 51% under visible light illumination (635 nm). In particular, it shows excellent stability over 1 month under ambient conditions. [ABSTRACT FROM AUTHOR]

Alloy nanoparticles have been widely investigated due to their unique properties and various applications. In particular, electrodes based on alloy nanomaterials can be good alternatives for advanced electrode fabrication due to their inherent, unique properties. Herein, we suggest a simple one-pot synthesis of Cu3Sn nanoparticles with high oxidation-resistivity, straightforward processability, and good electron conductivity. In addition, we introduce fabrication of pressure-assisted electrodes at room temperature with the synthesized Cu3Sn nanoparticles, which have good potential for various functional devices on a plastic substrate. [ABSTRACT FROM AUTHOR]

Solution-processed high-K dielectrics for oxide thin-film transistors (TFTs) have been widely studied with the objective of achieving high performance and low-cost TFTs for next-generation displays. In this study, we introduce an amorphous hafnium-lanthanum oxide (HfLaOx) gate insulator with high electrical permittivity which was fabricated by the simple spin-coating method. In particular, the solution-processed HfLaOx dielectric layer, which was achieved by a mixture of two Hf and La metal hydroxide precursors, showed amorphous properties, a low leakage current and a high dielectric constant. The solution-processed HfLaOx dielectric layers showed a breakdown voltage as high as 5 MV cm−1 in strength and a dielectric constant above 22. Based on their implementation as a gate insulator, the solution-processed ZnO/HfLaOx TFTs showed good and stable performances during operation at a low voltage. A mobility of μ = 1.6 cm2 V−1 s−1, an on/off current ratio of 106, and a threshold voltage of 0.0015 V were obtained under a 5 V gate bias. Our results show the possibility of the solution-processed amorphous HfLaOx dielectric layer as a gate insulator for oxide TFTs. We believe that this amorphous HfLaOx dielectric has good potential for next-generation high-performance TFT devices. [ABSTRACT FROM AUTHOR]

A solution-processed ionic amorphous Al2O3 dielectric with a low temperature annealing process at 350 °C shows good compatibility and high performance in metal oxide semiconductor thin film transitors (TFTs) such as Li–ZnO TFTs and In–ZnO TFTs. The Li–ZnO/Al2O3 and In–ZnO/Al2O3 TFTs, with solution-processability and low temperature annealing at a maximum of 350 °C, exhibited field-effect mobilities of 46.9 cm2 V−1 s−1 in crystalline Li–ZnO/Al2O3 TFTs and 44.2 cm2 V−1 s−1 in amorphous In–ZnO/Al2O3 TFTs with an on/off current ratio of more than 105. The proton mobile ion, such as hydrogen ion (H+) from chemisorbed water, in the ionic Al2O3 dielectric remarkably induces a high performance capacitance by the formation of an electrical double layer. The chemisorbed water was monitored by FT-IR and ellipsometric porosimetry measurements. Furthermore, the addition of H2O2 to the ionic Al2O3 dielectric precursor successfully suppressed the oxygen vacancies in the dielectric layer, which caused the electrical trap and pass, and confirmed the stable operation. These ionic amorphous Al2O3 dielectrics show good potential as switching TFTs devices in advanced displays, because they can satisfy the various demands of next-generation high-performance TFTs, such as low-cost, solution-processability, and a relatively low-temperature process. [ABSTRACT FROM AUTHOR]