Synergistic Effect of Size-Tailored Structural Engineering and Postinterface Modification for Highly Efficient and Stable Dye-Sensitized Solar Cells

Power conversion efficiency and its comparison of D-π-A and D-D-π-A structured photo-sensitizers

In this article as an extension of our prior research investigations, we discuss and compare the properties of indole-based D-π-A and D-D-π-A structured dyes and their photovoltaic performances. The photophysical aspects and electrochemical attributes of the previously reported D-π-A and D-D-π-A structured indole dyes were examined to figure out the thermodynamic feasibility of the dyes to perform as photosensitizers. Furthermore, these dyes were used to fabricate dye-sensitized solar cells (DSSCs) and their photovoltaic activity was assessed. The interfacial charge transfer in the DSSCs was identified using electrochemical impedance analysis (EIS). CB-K2K1S dye-based DSSC device expressed the fill factor (FF) of 0.65, contributing to the highest open-circuit voltage (VOC) of 645.3 mV and highest efficiency (η) of 4.33% since it has the highest short-circuit current density (JSC) of 9.8 mA cm-2, in contrast to MB-K2K1 dye which displayed VOC = 613.4 mV, JSC = 7.6 mA cm-2, FF = 0.63, η = 3.10%.

Recent advances in the approaches for improving the photovoltaic performance of porphyrin-based DSSCs

Among other photovoltaic techniques including perovskite solar cells and organic solar cells, dye-sensitized solar cells (DSSCs) are considered to be a potential alternative to conventional silicon solar cells. Porphyrins are promising dyes with the properties of easy modification and superior light-harvesting capability. However, porphyrin dyes still suffer from a number of unfavorable aspects, which need to be addressed in order to improve the photovoltaic performance. This feature article briefly summarizes the recent progress in improving the Voc and Jsc of porphyrin-based DSSCs in terms of molecular engineering by modifying the porphyrin macrocycle, donor and acceptor moieties of the porphyrin dyes, coadsorption of the porphrin dyes with bulky coadsorbents like chenodeoxycholic acid (CDCA), and cosensitization of the porphyrin dyes with metal-free organic dyes. Notably, concerted companion (CC) dyes are described in detail, which have been constructed by linking a porphyrin dye subunit and a metal-free organic dye subunit with flexible alkoxy chains to achieve panchromatic absorption and concerted enhancement of Voc and Jsc. In one sentence, this article is expected to provide further insights into the development of high performance DSSCs through the design and syntheses of efficient porphyrin dyes and CC dyes in combination with device optimization to achieve simultaneously elevated Voc and Jsc, which may inspire and promote further progress in the commercialization of the DSSCs.