The Role of Porphyrin-Free-Base in the Electronic Structures and Related Properties of N-Fused Carbazole-Zinc Porphyrin Dye Sensitizers

International Journal of Molecular Sciences

Xing-Yu Li²  Cai-Rong Zhang²  You-Zhi Wu³  Hai-Min Zhang²  Wei Wang²  Li-Hua Yuan²  Hua Yang²  Zi-Jiang Liu¹  Hong-Shan Chen⁴ 

[1] Department of Physics, Lanzhou City University, Lanzhou 730070, China;Department of Applied Physics, Lanzhou University of Technology, Lanzhou 730050, China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China;College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China;

关键词: porphyrin derivatives;    dye sensitizers;    electronic structures;    excited state;    density functional theory;   

DOI  :  10.3390/ijms161126057

来源: mdpi

【 摘 要 】

Dye sensitizers can significantly affect power conversion efficiency of dye-sensitized solar cells (DSSCs). Porphyrin-based dyes are promising sensitizers due to their performances in DSSCs. Here, based upon a N-fused carbazole-zinc porphyrin-free-base porphyrin triad containing an ethynyl-linkage (coded as DTBC), the novel porphyrin dyes named DTBC-MP and DTBC-TP were designed by varying the porphyrin-free-base units in the π conjugation of DTBC in order to study the effect of porphyrin-free-base in the modification of electronic structures and related properties. The calculated results indicate that, the extension of the conjugate bridge with the porphyrin-free-base unit results in elevation of the highest occupied molecular orbital (HOMO) energies, decrease of the lowest unoccupied molecular orbital (LUMO) energies, reduction of the HOMO-LUMO gap, red-shift of the absorption bands, and enhancement of the absorbance. The free energy changes demonstrate that introducing more porphyrin-free-base units in the conjugate bridge induces a faster rate of electron injection. The transition properties and molecular orbital characters suggest that the different transition properties might lead to a different electron injection mechanism. In terms of electronic structure, absorption spectra, light harvesting capability, and free energy changes, the designed DTBC-TP is a promising candidate dye sensitizer for DSSCs.

【 授权许可】

CC BY   
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