Synthesis, characterization and photovoltaic application of a new magnetic nanocomposite from polyaniline-Fe[formula omitted]O[formula omitted]-TiO[formula omitted

Abstract

For many organic solar cells, the energy loss in separating closely coupled electron–hole pairs in low-mobility materials is high. In polymer solar cells (PSCs), photogenerated charge carrier recombination inside the PSCs and limited charge carrier mobility of disordered organic materials accounts for roughly 50% of the total efficiency loss. To solve these problems, in this work, we introduce magnetic Fe3O4 nanoparticles into the active layer of polymer solar cells. Specifically, an environmentally friendly and facile in situ method for the synthesis of a PANI-Fe3O4-TiO2 nanocomposite without the need for an organic solvent is described. The nanocomposite’s structural, thermal, morphological, optical, electrochemical and photovoltaic characteristics are studied. The TEM micrographs of the synthesized nanocomposite show the nanoplate structure of PANI, which is covered by Fe3O4 and TiO 2 nanoparticles. Because of the spin–orbit coupling effect of Fe3O4 on PANI, the band gap energy of the nanocomposite revealed an indirect electron transfer. The P–N heterojunction solar cell based on this nanocomposite, with a device structure of FTO/TiO2/PANI-Fe3O4-TiO2/Al, exhibited an improved power conversion efficiency (PCE) compared to the device without Fe3O4. Spin–orbit coupling and/or singlet fission induced by magnetic Fe3O4 nanoparticles is thought to effectively increase the number of triplet excitons, thereby suppressing the recombination process.