Enhanced photovoltaic performance of Cu-doped NiO nanoparticles functionalized with organic dyes for solid-state DSSCs

This study demonstrates the facile co-precipitation synthesis of pristine and Cu-doped NiO nanoparticles to investigate their potential for solid-state dye sensitized solar cells (ssDSSCs). The materials have been comprehensively characterized by different analytical techniques to confirm phase purity, structural, optical, and morphological properties. A clear red shift has been observed for pristine NiO of 307 nm to Cu-doped NiO 346 nm with various Cu contents (1-5%) along with a significant band gap reduction from 3.45 eV to 2.82 eV which improves the visible light absorption range. The nanohybrid materials were prepared by grafting different organic dyes with pristine and Cu-doped NiO nanoparticle. The dye functionalized materials showed an extension in the broad absorption from 400 to 698 nm for carminic acid while 448–800 nm for arsenazo III, respectively. The red shift in the dye spectra after the grafting confirmed the successful chemisorption phenomenon. Furthermore, the disappearance of a few bands in the FTIR spectra of dyes in materials also indicates the attachment of dyes molecules with pristine and Cu-doped NiO nanoparticles. A blend of photoactive material based on nanoparticles, dyes, and poly(3-hexylthiophene) (P3HT) was used to fabricate the device for ssDSSC applications. Among all the fabricated devices, P3HT-Cu-NiO-AR performed excellent with maximum efficiency of 1.01% with short-circuit current density of 4.42 mA cm⁻² compared to the refence cell of P3HT-NiO (0.07%). This performance indicates that the Cu doping, and dye functionalization synergistically improves the NiO optoelectronic properties resultantly showed its potential for photoanode material for next generation ssDSSCs.