Natural Chlorophyll-Related Porphyrins and Chlorins for Dye-Sensitized Solar Cells

Molecules

Xiao-Feng Wang¹ 

[1] Research Center for Organic Electronics, Graduate School of Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan

关键词: porphyrin;    chlorin;    dye-sensitized solar cell;    photosynthesis;    organic photovoltaics;   

DOI  :  10.3390/molecules17044484

来源: mdpi

【 摘 要 】

Natural-chlorophyll-related porphyrins, including (2H, Zn, Cu)-protoporphyrin IX (Por-1) and Zn-mesoporphyrin IX (Por-2), and chlorins, including chlorin e₆ (Chl-1), chlorin e₄ (Chl-2), and rhodin G₇ (Chl-3), have been used in dye-sensitized solar cells (DSSCs). For porphyrin sensitizers that have vinyl groups at the β-positions, zinc coordinated Por-1 gives the highest solar-energy-to-electricity conversion efficiency (η) of up to 2.9%. Replacing the vinyl groups of ZnPor-1 with ethyl groups increases the open-circuit voltage (V_oc) from 0.61 V to 0.66 V, but decreases the short-circuit current (J_sc) from 7.0 mA·cm⁻² to 6.1 mA·cm⁻² and the value of η to 2.8%. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations suggest that the higher J_sc values of Zn-based porphyrin sensitizers result from the favorable electron injection from the LUMO at higher energy levels. In the case of the chlorin sensitizers, the number of carboxyl protons has a large effect on the photovoltaic performance. Chl-2 with two carboxyl protons gives much higher values of J_sc, V_oc, and η than does Chl-1 with three carboxyl protons. Replacing the protons of Chl-1 with sodium ions can substantially improve the photovoltaic performance of Chl-1-based solar cells. Furthermore, the sodium salt of Chl-3 with an aldehyde group at the C7 position shows poorer photovoltaic performance than does the sodium salt of Chl-1 with methyl groups at the C7 position. This is due to the low light-harvesting capability of Chl-3.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.