Bilayer Chlorophyll-Based Biosolar Cells Inspired from the Z-Scheme Process of Oxygenic Photosynthesis

Abstract

The Z-scheme process in chlorophyll-based natural photosynthesis shows the pathway of photoinduced electron transport from photosystem II (PSII) to photosystem I (PSI) through an electron transfer chain. Inspired by the interesting Z-scheme of oxygenic photosynthesis, we imitated the dual photosynthesis systems into biosolar cells (BSCs). The device structure fabricated here is ITO/ZnO/Chl-A/Chl-D1, -D2, -D3, or -D4 (Chl-Ds)/MoO 3 /Ag. Due to higher HOMO/LUMO energy levels of Chl-A than those of Chl-Ds, the sublayer Chl-A corresponds to PSI, and the upper layer Chl-Ds are equivalent to PSII, leading to double photoexcited electron transfer from Chl-Ds to Chl-A. The energy alignment of the photoactive layers here is in conflict with the traditional comprehension of photovoltaic devices. Interestingly, such an uncommon device can still work well. A power conversion efficiency of 1.30% was reached based on the Chl-A/Chl-D4 device under standard AM1.5 illumination.

Chlorophyll-based organic solar cells with improved power conversion efficiency

“…2 (a) and (b) [37] . This may be attributed to the π -π stacking interactions between adjacent molecules [38,39] .…”

Semisynthetic Chlorophyll Derivatives Toward Solar Energy Applications

“…Although the energy level of PSI is higher than that of PSII, the electrons can transfer from PSII to PSI through electron transport chain (Figure a). Inspired from this interesting natural electron transfer, we proposed a new BSC system using sequentially spin‐coated ZnChl‐9 mimicking PSI and four kinds of ambipolar zinc or free‐base chlorophyll derivatives (Zn)Chl‐46,47 simulating PSII, which was compared and determined by analyzing the energy levels of ZnChl‐9 and (Zn)Chl‐46,47 to the natural PSs (Figure b) …”

“…Schematic drawing of a) natural Z‐scheme of oxygenic photosynthesis, b) BL and c) trilayer chlorophyll derivatives‐based BSC systems mimicking the natural Z‐scheme of oxygenic photosynthesis, and device structure of the d) BL and e) trilayer BSC systems. Reproduced with permission . Copyright 2018 and 2019, American Chemical Society.…”

Chlorosome‐Like Molecular Aggregation of Chlorophyll Derivative on Ti3C2Tx MXene Nanosheets for Efficient Noble Metal‐Free Photocatalytic Hydrogen Evolution

“…The intriguing physical properties of chlorosomal antenna systems have stimulated some applications of chlorophyll aggregates in photovoltaic devices such as perovskite solar cells and biosolar cells. [ 18,20–22 ] The special light trapping, electron/excited state migration, and hole back‐transfer of chlorophyll aggregates are also the basis for effectively suppressing electron–hole recombination, which is important to improve the efficiency of HER. Therefore, incorporation of chlorophyll aggregates in the photocatalytic HER systems must be of great potential.…”