Abstract: A solar vapor generator system and method are provided. In some embodiments, the system has near perfect energy conversion efficiency in the process of solar vapor generation below room temperature. Remarkably, when the operation temperature of the system is below that of the surroundings, the total vapor generation will be higher than the upper limit that can be produced by the input solar energy.

Abstract: Structures and methods for Surface-Enhanced Raman Spectroscopy (SERS) are presented. In some embodiments, a SERS structure includes a ground plate with a spacer layer disposed thereon. A first plurality of metallic nanostructures is disposed on the spacer layer such that a portion of the spacer layer is exposed in gaps formed between the nanostructures of the first plurality of metallic nanostructures. In some embodiments, a first metallic layer is annealed to form the first plurality of metallic nanostructures. A second plurality of metallic nanostructures is disposed on the spacer layer in the gaps of the first plurality of metallic nanostructures. In some embodiments, a second metallic layer is annealed to form the second plurality of metallic nanostructures.

Abstract: Disclosed herein are systems and methods for passively cooling water vapor to enable efficient condensation, and methods of making such systems. A passive cooler can include a thermally conductive substrate having a first side and a second side opposite the first side, a coating disposed on at least a portion of the first side of the substrate, and a housing having one or more insulative walls. The insulative walls may define a vapor flow channel from an inlet to an outlet of the housing such that the second side of the substrate is exposed to water vapor flowing through the vapor flow channel.

Abstract: A passive cooler of the disclosure includes a thermal emitter having a substrate and a coating disposed on at least a portion of a first side of the substrate. The cooler has a beam guide made from a material having a high absorption to solar wavelengths and high reflectance at mid-infrared wavelengths. The beam guide is configured such that at least a portion of incident light is acted on by the beam guide before reaching the thermal emitter. In some embodiments, the beam guide has a graded optical index.

Abstract: Disclosed herein are systems and methods for passively cooling water vapor to enable efficient condensation, and methods of making such systems. A passive cooler can include a thermally conductive substrate having a first side and a second side opposite the first side, a coating disposed on at least a portion of the first side of the substrate, and a housing having one or more insulative walls. The insulative walls may define a vapor flow channel from an inlet to an outlet of the housing such that the second side of the substrate is exposed to water vapor flowing through the vapor flow channel.

Abstract: Optoelectronic devices that use very thin single-crystalline inorganic semiconductor films as phonon-absorbing layers in combination with non-lattice optical cavities are provided.

Abstract: A solar vapor generator system and method are provided. In some embodiments, the system has near perfect energy conversion efficiency in the process of solar vapor generation below room temperature. Remarkably, when the operation temperature of the system is below that of the surroundings, the total vapor generation will be higher than the upper limit that can be produced by the input solar energy.

Abstract: Optoelectronic devices that use very thin single-crystalline inorganic semiconductor films as phonon-absorbing layers in combination with non-lattice optical cavities are provided.