C-rich carbon nitride conjugated polymer enabling all-solid-state photo-rechargeable cell

Photo-rechargeable devices capable of harvesting sunlight and storing solar energy are the most prospective strategy to address the issue of intermittent availability of sunlight. All-solid-state energy storage devices possess advantages of long-term stability, safety and integrability. Herein, we propose a design of all-solid-state photo-rechargeable cells, which consists of the C-rich carbon nitride conjugated polymer (denoted as CPCN), TiO 2 nanocrystalline layer and FTO (Fluorine-doped Tin oxide) conducting glass, without electrolytes. The cell is designed as FTO//TiO 2 //CPCN//TiO 2 //FTO, in which CPCN performs light absorption, photo-carrier generation and charge storage. TiO 2 serves as the photocharge-stabilizing and -transporting material. A novel all-solid-state charge storage concept of “bottling” photoelectrons is thus presented, which integrates photo-charge separation of solar cells with charge storage of dielectric capacitors. Owing to the extraordinary optical-electrical synergism, the cell achieves a specific photocharge capacity of 274.3 mC cm −2 (618.3C g −1 ), as well as the merits of the remarkable enhancement of photocharge-storage capacity in parallel modes and no performance decay with the cell size increasing. • C-rich carbon nitrides (CPCN) accumulate photoelectrons on the conduction band. • TiO 2 nanocrystals perform excellent charge stabilization on CPCN/TiO 2 interfaces. • Synergism of CPCN and TiO 2 achieves high performance photocharge storage. • TiO 2 /CPCN/TiO 2 enables non electrochemical all-solid-state photocharge storage.