To achieve air-tolerant and efficient low-power upconverting devices that are environmentally and economically friendly, we are optimizing and evaluating a novel matrix for triplet-triplet annihilation-based photon upconversion (TTA-UC) with biological materials. Here we report the first example of a self-healing protein-lipid hydrogel, incorporated with a chromophore pair, to overcome limitations of current upconversion systems, such as poor water-solubility of chromophores, disturbance of oxygen molecules, complicated and time-consuming preparation, etc. In our hydrogel system, the chromophores are solubilized in a protein solution with lipid micelles, which are further stabilized and buried in a 3-D protein network. The protein sol-gel transition is irreversible and formed via thermal treatment. The gelation is attributed to weak physical interactions among protein molecules with partial denaturation, allowing simple self-healing of the hydrogel via contact between the damaged surfaces and applied heat. This is a robust, facile, and simple strategy to prepare free-standing, moldable, biocompatible, and biodegradable hydrogels, which contain about 75% water and are completely transparent. The concentrations of chromophores are adjusted for efficient photon upconversion from the donor, with a longer wavelength absorption band, to the acceptor, with a shorter wavelength emission band. Thus, the excitation of the donor, with a commercial 532 nm laser, results in an intense blue emission with a higher energy from the accepter, which can be visualized by the naked eye. Furthermore, this protein hydrogel can be formed interlocking with cellulose fiber on a piece of regular filter paper. This hydrogel has potential in solar cell and LED panel coatings for increased efficiency as well as device display and sensing applications.

Self-healing hydrogels by thermal-induced protein-lipid co-assembly for air-tolerant photon upconversion

2019 Spring National Meeting

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