The present invention relates to additive manufacturing methods, in which crystalline materials can be formed by using a liquid precursor. In particular embodiments, the crystalline material is a perovskite. The methods include the use of a thermal voxel, which can be translated to form any arbitrary pattern of initial crystalline seed structure(s). Then, the seed structure can be incubated to promote crystal growth and/or crystal dissolution, thereby providing a patterned crystalline material.

A method for growing a crystalline composition, the first crystalline composition may include gallium and nitrogen. The crystalline composition may have an infrared absorption peak at about 3175 cm.sup.1, with an absorbance per unit thickness of greater than about 0.01 cm.sup.1. In one embodiment, the composition may have an amount of oxygen present in a concentration of less than about 310.sup.18 per cubic centimeter, and may be free of two-dimensional planar boundary defects in a determined volume of the first crystalline composition.

A solution deposition method includes: applying a liquid precursor solution to a substrate, the precursor solution including an oxide of a first metal, a hydroxide of the first metal, or a combination thereof, dissolved in an aqueous ammonia solution; evaporating the precursor solution to directly form a solid seed layer on the substrate, the seed layer including an oxide of the first metal, a hydroxide of the first metal, or a combination thereof, the seed layer being substantially free of organic compounds; and growing a bulk layer on the substrate, using the seed layer as a growth site or a nucleation site.

A solution deposition method includes: applying a liquid precursor solution to a substrate, the precursor solution including an oxide of a first metal, a hydroxide of the first metal, or a combination thereof, dissolved in an aqueous ammonia solution; evaporating the precursor solution to directly form a solid seed layer on the substrate, the seed layer including an oxide of the first metal, a hydroxide of the first metal, or a combination thereof, the seed layer being substantially free of organic compounds; and growing a bulk layer on the substrate, using the seed layer as a growth site or a nucleation site.

The present process provides a method for synthesizing difficult to make oxide-free nanometals and such as Zn, Sn and Ti and alloys of the period 4 and 5 transition metal elements in a free and reduced state using a solution phase synthesis process. Also provided is a method for stabilizing their associated colloidal metal and alloy dispersions under kinetic control at modest temperatures (<95 degrees Celsius). A solution of an organic reducing agent containing at least two proximal nitrogen atoms is reacted with a separate solution containing one or more metal-organic salts dissolved in the same or different low molecular weight solvent as the reducing agent. The reaction products are stabilized with Lewis bases and Lewis acids and optionally can be concentrated by removing a portion of the volatile low molecular weight solvent by either the use of a partial vacuum or by chemical extraction into another phase.

The present process provides a method for synthesizing difficult to make oxide-free nanometals and such as Zn, Sn and Ti and alloys of the period 4 and 5 transition metal elements in a free and reduced state using a solution phase synthesis process. Also provided is a method for stabilizing their associated colloidal metal and alloy dispersions under kinetic control at modest temperatures (<95 degrees Celsius). A solution of an organic reducing agent containing at least two proximal nitrogen atoms is reacted with a separate solution containing one or more metal-organic salts dissolved in the same or different low molecular weight solvent as the reducing agent. The reaction products are stabilized with Lewis bases and Lewis acids and optionally can be concentrated by removing a portion of the volatile low molecular weight solvent by either the use of a partial vacuum or by chemical extraction into another phase.

Provided herein are mechanically interlocked air-stable persistent organic radicals. The radical compositions may access a multiplicity of radical, cationic redox states as well as a fully cationic redox state. A composition comprises a first ring mechanically interlocked with a second ring or a salt thereof, wherein the first ring comprises a 4,4-bipyridinium subunit or a derivative thereof and a diazapyrenium subunit or a derivative thereof and the second ring comprises a 4,4-bipyridinium subunit or a derivative thereof. In some embodiments, the second ring further comprises a diazapyrenium subunit or a derivative thereof. Methods of preparing the compositions are also provided.

Provided herein are mechanically interlocked air-stable persistent organic radicals. The radical compositions may access a multiplicity of radical, cationic redox states as well as a fully cationic redox state. A composition comprises a first ring mechanically interlocked with a second ring or a salt thereof, wherein the first ring comprises a 4,4-bipyridinium subunit or a derivative thereof and a diazapyrenium subunit or a derivative thereof and the second ring comprises a 4,4-bipyridinium subunit or a derivative thereof. In some embodiments, the second ring further comprises a diazapyrenium subunit or a derivative thereof. Methods of preparing the compositions are also provided.

Microfluidic structures and methods for manipulating fluids and reactions are provided. Such structures and methods may involve positioning fluid samples, e.g., in the form of droplets, in a carrier fluid (e.g., an oil, which may be immiscible with the fluid sample) in predetermined regions in a microfluidic network. In some embodiments, positioning of the droplets can take place in the order in which they are introduced into the microfluidic network (e.g., sequentially) without significant physical contact between the droplets. Because of the little or no contact between the droplets, there may be little or no coalescence between the droplets. Accordingly, in some such embodiments, surfactants are not required in either the fluid sample or the carrier fluid to prevent coalescence of the droplets. Structures and methods described herein also enable droplets to be removed sequentially from the predetermined regions.

Microfluidic structures and methods for manipulating fluids and reactions are provided. Such structures and methods may involve positioning fluid samples, e.g., in the form of droplets, in a carrier fluid (e.g., an oil, which may be immiscible with the fluid sample) in predetermined regions in a microfluidic network. In some embodiments, positioning of the droplets can take place in the order in which they are introduced into the microfluidic network (e.g., sequentially) without significant physical contact between the droplets. Because of the little or no contact between the droplets, there may be little or no coalescence between the droplets. Accordingly, in some such embodiments, surfactants are not required in either the fluid sample or the carrier fluid to prevent coalescence of the droplets. Structures and methods described herein also enable droplets to be removed sequentially from the predetermined regions.