Photon upconverting bioplastics with high efficiency and in-air durability

Abstract

There is an urgent demand for substituting synthetic plastics to bioplastics for sustainable renewable energy production. Here, we report a simple one-step approach to create bioplastics with efficient and durable photon upconversion (UC) by encapsulating non-volatile chromophore solutions into collagen-based protein films. By just drying an aqueous solution of gelatin, surfactant, and UC chromophores (sensitizer and annihilator), liquid surfactant microdroplets containing the UC chromophores are spontaneously confined within the gelatin films. Thanks to the high fluidity of microdroplets and the good oxygen barrier ability of the collagen-based fiber matrices, a high absolute TTA–UC efficiency of 15.6% and low threshold excitation intensity of 14.0 mW cm⁻² are obtained even in air. The TTA–UC efficiency was retained up to 8.2% after 2 years of storage under ambient conditions, hence displaying the significant durability desired for practical applications.