Abstract: A method of ligand-induced regional modification of a perovskite film of perovskite optoelectronic device can include generating a ligand atmosphere, exposing a perovskite optoelectronic device in the ligand atmosphere, and removing the perovskite optoelectronic device from the ligand atmosphere. Methods for improving the performance and stability of perovskite optoelectronic devices are performed by using a ligand-induced modification of complete devices at room temperature. This post-device treatment, completely separated from the fabrication process of common perovskite optoelectronic devices, provides a general strategy to improve the stability of different completed perovskite optoelectronic devices (i.e., perovskite solar cells, perovskite light-emitting diodes, and photodetectors) without introducing any undesirable impurities during device fabrication.

Abstract: Methods for preparation of surfactant-free ultra-small spinel ternary metal oxide nanoparticles are provided. A method comprises dissolving first and second metal salts in deionized water in a specific mole ratio to form a solution comprising two different metal ions, applying a coprecipitation method and adding an alkaline solution to the solution to form a colloidal suspension, wherein a colloid of the colloidal suspension is a metal hydroxide, adjusting the amount and the addition rate of the alkaline solution to form a specific structure of metal hydroxide precipitate; washing and drying the metal hydroxide to form a structured metal hydroxide powder, and applying a calcination method to the structured metal hydroxide powder to form a surfactant-free spinel-type (AB2O4) ternary metal oxide, wherein A and B each respectively comprise a metal element.

Abstract: A solid-liquid-solid phase transformation (SLSPT) approach is used for fabrication of perovskite periodic nanostructures. The pattern on a mold is replicated by perovskite through phase change of perovskite from initially solid state, then to liquid state, and finally to solid state. The LED comprising perovskite periodic nanostructure shows better performance than that with flat perovskite. Further, the perovskite periodic nanostructure from SLSPT can be applied in many optoelectronic devices, such as solar cells, light emitting diodes (LED), laser diodes, transistors, and photodetectors.

Abstract: A solid-liquid-solid phase transformation (SLSPT) approach is used for fabrication of perovskite periodic nanostructures. The pattern on a mold is replicated by perovskite through phase change of perovskite from initially solid state, then to liquid state, and finally to solid state. The LED comprising perovskite periodic nanostructure shows better performance than that with flat perovskite. Further, the perovskite periodic nanostructure from SLSPT can be applied in many optoelectronic devices, such as solar cells, light emitting diodes (LED), laser diodes, transistors, and photodetectors.

Abstract: Methods for preparation of surfactant-free ultra-small spinel ternary metal oxide nanoparticles are provided. A method comprises dissolving first and second metal salts in deionized water in a specific mole ratio to form a solution comprising two different metal ions, applying a coprecipitation method and adding an alkaline solution to the solution to form a colloidal suspension, wherein a colloid of the colloidal suspension is a metal hydroxide, adjusting the amount and the addition rate of the alkaline solution to form a specific structure of metal hydroxide precipitate; washing and drying the metal hydroxide to form a structured metal hydroxide powder, and applying a calcination method to the structured metal hydroxide powder to form a surfactant-free spinel-type (AB2O4) ternary metal oxide, wherein A and B each respectively comprise a metal element.

Abstract: A method of ligand-induced regional modification of a perovskite film of perovskite optoelectronic device can include generating a ligand atmosphere, exposing a perovskite optoelectronic device in the ligand atmosphere, and removing the perovskite optoelectronic device from the ligand atmosphere. Methods for improving the performance and stability of perovskite optoelectronic devices are performed by using a ligand-induced modification of complete devices at room temperature. This post-device treatment, completely separated from the fabrication process of common perovskite optoelectronic devices, provides a general strategy to improve the stability of different completed perovskite optoelectronic devices (i.e., perovskite solar cells, perovskite light-emitting diodes, and photodetectors) without introducing any undesirable impurities during device fabrication.