Abstract: The present invention relates to methods and systems for volumetric printing a three-dimensional object. The methods and systems include achieving polymerization in a photopolymerizable liquid at the intersection of a first optical projection of excitation light and second optical projection of excitation light comprising a sheet of excitation light.

Abstract: Articles and methods for increasing the triplet upconversion threshold, e.g., by utilizing a triplet exciton acceptor lower in energy than the sensitizer or upconverter, are generally described. Some embodiments, for example, are directed to articles and methods that use a triplet sensitizer, an upconverter, and an acceptor to produce upconverted photons (e.g., light of a second energy). The light can be used to polymerize a polymerizable species. Other upconversion configurations can also be used in other embodiments. In some cases, this may allow true 3D printing to be achieved due to improved control of light absorption, e.g., without needing to “print” on a layer-by-layer basis.

Abstract: The present invention generally relates to photon upconversion nanocapsules for 3D printing and other applications. For example, one aspect is generally related to nanocapsules that contain an upconversion material. Light, such as laser light, focused on a region of liquid containing nanocapsules may be upconverted by the upconversion material to produce wavelengths sufficient to cause polymerization of a polymerizable entity to occur. However, in contrast, although other regions may receive some light, that light may not be of sufficient focus or intensity to be upconverted, and thus, the polymerizable entity in those regions would generally not polymerize. In such a fashion, the extent of polymerization can be controlled, for example, by controlling where light is applied to the liquid. The light could be focused at arbitrary regions within the liquid, thus allowing true 3D-printing to occur.

Abstract: Various exemplary photoreactions can be provided, including reactions generally based on triplet-triplet annihilation upconversion. Representative photosensitizers include PdPc(OBu)8 and PtTPTNP. Representative annihilators include FDPP and TTBP. Such exemplary photoreactions, systems and methods may be used in a variety of applications, including various biological or physical applications. Exemplary methods can also be provided for making or using such systems, photoreactions, kits including such systems, or the like.

Abstract: The present invention generally relates to composition and methods for downconverting light. In some embodiments, the composition and methods comprise an organic material, a nanocrystal, and a ligand capable of facilitating energy transfer between the organic material and the nanocrystal. In certain embodiments, the nanocrystal has a first excited energy state with an energy less than a triplet energy state of the organic material. The organic material, in some embodiments, may be aromatic and/or include one or more pi-conjugated carbon-carbon double bonds. In some cases, incident light may be absorbed by the organic material to produce two triplet excitons. The triplet excitons may then transfer to the nanocrystal via the ligand, where they can undergo recombination, resulting in the formation low energy photons.

Abstract: The present invention generally relates to composition and methods for upconverting light. In some embodiments, the composition and methods comprise an organic material, a nanocrystal, and a ligand capable of facilitating energy transfer between the nanocrystal and the organic material. In certain embodiments, the nanocrystal has a first excited energy state with an energy greater than a triplet state of the organic material. The organic material, in some embodiments, may be aromatic and/or include one or more pi-conjugated carbon-carbon double bonds. In some cases, incident light may be absorbed by the nanocrystal to produce triplet excitons. The triplet excitons may then transfer from the nanocrystal to the organic material and undergo triplet-triplet annihilation, creating a singlet state of approximately twice the energy of the triplet exciton. In certain embodiments, the singlet state fluoresces, resulting in the formation of a high energy photon.

Abstract: The present invention generally relates to composition and methods for upconverting light. In some embodiments, the composition and methods comprise an organic material, a nanocrystal, and a ligand capable of facilitating energy transfer between the nanocrystal and the organic material. In certain embodiments, the nanocrystal has a first excited energy state with an energy greater than a triplet state of the organic material. The organic material, in some embodiments, may be aromatic and/or include one or more pi-conjugated carbon-carbon double bonds. In some cases, incident light may be absorbed by the nanocrystal to produce triplet excitons. The triplet excitons may then transfer from the nanocrystal to the organic material and undergo triplet-triplet annihilation, creating a singlet state of approximately twice the energy of the triplet exciton. In certain embodiments, the singlet state fluoresces, resulting in the formation of a high energy photon.

Abstract: The present invention generally relates to composition and methods for downconverting light. In some embodiments, the composition and methods comprise an organic material, a nanocrystal, and a ligand capable of facilitating energy transfer between the organic material and the nanocrystal. In certain embodiments, the nanocrystal has a first excited energy state with an energy less than a triplet energy state of the organic material. The organic material, in some embodiments, may be aromatic and/or include one or more pi-conjugated carbon-carbon double bonds. In some cases, incident light may be absorbed by the organic material to produce two triplet excitons. The triplet excitons may then transfer to the nanocrystal via the ligand, where they can undergo recombination, resulting in the formation low energy photons.

Abstract: Embodiments described herein relate to devices containing photoactive materials that, in some cases, undergo singlet fission. In some cases, the devices (e.g., solar cells) can efficiently convert photonic energy into usable electricity, with external quantum efficiencies greater than 100% in the visible region.