Sonochemical replication of chloroplast with titania for light harvesting

Hierarchy structure of granum in chloroplast was replicated onto titania using a simple and tactical sonochemical method and calcination. The structures of TiO2 replicas were characterized by XRD, FE-SEM and TEM and the pore structures were characterized by N2 adsorption/desorption. As a comparison, the preparation without sonication by using impregnation then calcination method was conducted, which shows the efficiency of the ultrasound on the exact replication of granum from micrometers down to nanometers. The optical properties of the TiO2 replica, the chloroplast and the commercial pure TiO2 powder together with the compared replica were measured by absorbance spectroscopy. It was found that the absorbance intensity of the TiO2 replica made by ultrasonication is much better than the soaked one, and is twice of that of the pure TiO2 powder in ultraviolet – visible light range. The excellent light harvesting performance of the TiO2 is attributed to the combination of the functionality from the inorganic oxide and the fine hierarchical biological structures.