Screening novel XY1b-based organic dyes by modifying electron-assisted acceptors for dye-sensitised solar cells: a theoretical analysis

Abstract

To screen efficient organic dyes, six novel XY1b-based molecules are designed by modifying electron-assisted acceptors, and their electronic structure, optical properties and photovoltaic performances are evaluated in detail with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations coupled with the incoherent charge transfer model. Results show that benzoselenadiazole (BSD) and diketopyrrolopyrrole (DPP) are two best electron-assisted acceptors and replacing benzothiadiazole (BTD) with the BSD/DPP unit can redshift the maximum absorption peak by 13/67 nm. According to our estimation, the overall photoelectric conversion efficiency (PCE) of XY1b is as high as 13.09% with a J_sc of 16.261 mA·cm⁻², V_oc of 1.047 V and FF of 0.769, in good agreement with its measured value of 11.8 ± 0.2% (J_sc= 15.26 ± 0.18 mA·cm⁻², V_oc= 1.01 ± 0.003 V and FF = 76.3 ± 0.2%), verifying that the scheme proposed by us is reliable. With the same procedure, the predicted PCE values for dyes 1, 2 and 5 reach up to 18.00%, 15.95% and 27.37% respectively, indicating that these three dyes are potential efficient sensitisers and are worthy of further study by experiments.

GRAPHICAL ABSTRACT

KEYWORDS:

• Density functional theory
• D-A'-π-A frameworks
• photovoltaic performances

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data used in this work is provided in the manuscript or in the supporting information.

Additional information

Funding

We gratefully acknowledge the financial support by the National Natural Science Foundation of China (22273053 and 22073059).