Trilayer Chlorophyll-Based Cascade Biosolar Cells

Inspired by the mimic of dual charge separation in natural photosynthesis systems for biosolar cells (BSCs) applications where the charge extraction at the interface was insufficient, we report chlorophyll (Chl)-based trilayer cascade BSCs composed of Chl-C1 and/or a Chl-C2 (Chl-C)-sensitized mesoporous TiO2 layer (TiO2–Chl-C) acting as electron extraction layers as well as active layers to simulate the primary electron acceptor and two additional Chl derivatives layers (Chl-A/Chl-D) mimicking the reaction centers of photosystems I and II in the Z-scheme process of natural oxygenic photosynthesis. All of the Chls could be excited to generate photocurrent, which is similar to the natural photosynthesis of multipigment synergy. The charge extraction has a significant enhancement compared to bilayer BSCs. Co-sensitization of Chl-C1 with Chl-C2 could further enhance the electron injection efficiency at the TiO2–Chl-C interface, leading to a power conversion efficiency of 4.14%, which is more than 3 times larger than that of the bilayer system.