Polyimide-Based Covalent Organic Framework as a Photocurrent Enhancer for Efficient Dye-Sensitized Solar Cells

Pei-Hsuan Chang; Manik Chandra Sil; Kamani Sudhir K Reddy; Ching-Hsuan Lin; Chih-Ming Chen

doi:10.1021/acsami.2c04507

Polyimide-Based Covalent Organic Framework as a Photocurrent Enhancer for Efficient Dye-Sensitized Solar Cells

ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25466-25477. doi: 10.1021/acsami.2c04507. Epub 2022 May 23.

Authors

Pei-Hsuan Chang¹, Manik Chandra Sil¹, Kamani Sudhir K Reddy¹, Ching-Hsuan Lin¹, Chih-Ming Chen^{1

2}

Affiliations

¹ Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan.
² Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University, Taichung 402, Taiwan.

PMID: 35604330
DOI: 10.1021/acsami.2c04507

Abstract

Covalent organic frameworks (COFs) are of great interest in the energy and optoelectronic fields due to their high porosity, superior thermal stability, and highly ordered conjugated architecture, which are beneficial for charge migration, charge separation, and light harvesting. In this study, polyimide COFs (PI-COFs) are synthesized through the condensation reaction of pyromellitic dianhydride (PMDA) with tris(4-aminophenyl) amine (TAPA) and then doped in the TiO₂ photoelectrode of a dye-sensitized solar cell (DSSC) to co-work with N719 dye to explore their functionality. As a benchmark, the pristine DSSC without the doping of PI-COFs exhibits a power conversion efficiency of 9.05% under simulated one sun illumination. The doping of 0.04 wt % PI-COFs contributes an enhanced short-circuit current density (J_SC) from 17.43 to 19.03 mA/cm², and therefore, the cell efficiency is enhanced to 9.93%. The enhancement of J_SC is attributed to the bifunctionality of PI-COFs, which enhances the charge transfer/injection and suppresses the charge recombination through the host (PI-COF)-guest (N719 dye) interaction. In addition, the PI-COFs also function as a cosensitizer and contribute a small quantity of photoinduced electrons upon sunlight illumination. Surface modification of oxygen plasma improves the hydrophilicity of PI-COF particles and reinforces the heterogeneous linkage between PI-COF and TiO₂ nanoparticles, giving rise to more efficient charge injection. As a result, the champion cell exhibits a high power conversion efficiency of 10.46% with an enhanced J_SC of 19.43 mA/cm². This methodology of increasing solar efficiency by modification of the photoelectrode with the doping of PI-COFs in the TiO₂ nanoparticles is promising in the development of DSSCs.

Keywords: PI-COF; cell efficiency; charge injection; photoelectrode; plasma treatment.