Researchers at the International Advanced Research Center for Powder Metallurgy and New Materials, India, claimed that they have increased the efficiency and stability of Titanium dioxide (TiO₂)-nanorods-based perovskite solar cells using a new process.

The researchers devised a process varying the length and porosity of TiO₂-nanorods to develop stable light-harvesting active layers. They established a correlation between the lengths of TiO₂-nanorods and the porosity of the electrode for the ambient processed perovskite solar cells.

To enhance the efficiency and stability of solar cells, the researchers controlled nanostructures of TiO₂-nanorods by varying the concertation of titania precursor and the growth time.

The researchers explained that electrodes’ porosity plays a vital role in perovskite infiltration and sensitization. The inter-pore distance between two TiO₂ nanorods determines the porosity of photo-electrodes, and the porosity varies in line with the growth of nanorod length increases.

“In this work, we had precise control over the length, porosity, and morphology of TiO₂-nanorods from compact film to nanostructured film,” said the researchers.

They developed perovskite solar cells with 350nm TiO₂-nanorods that exhibited better efficiency when compared with the conventional Titanium dioxide nanoparticles (NP-TiO₂). The similar thickness of NP-TiO₂-based device exhibited less photocurrent value than nanorods-TiO₂, which was attributed to the dense packing of 20nm TiO₂ particles inhibiting the loading of perovskite. The high crystallinity of the TiO₂-nanorods provided a low resistance to the flow of electrons in the electron transport layer. The crystalline structure of the electron transport layer also significantly influenced the stability of perovskite solar cells.

The research team lead, Dr. V. Ganapathy,  explains, “The decomposition of perovskite absorber is a critical factor behind the performance degradation of perovskite solar cells. Given the similar nature of perovskite, enhanced stability of TiO₂-nanorod perovskite solar cell is attributed to slow ion migration across thermodynamically stable rutile TiO₂-nanorods/MAPbl₃ interface.”

Perovskite solar cells are commercially attractive because of their potential to achieve higher efficiencies at low production costs. They have seen constant experimentation by various research teams to help enhance its long-term stability.

In July 2021, a team of researchers from the University of Arizona worked on a new printing process called restricted area printing by ink drawing to improve the stability and efficiency of perovskite solar cells.

Mercom had earlier reported that researchers at the ITMO University’s School of Engineering developed a paste of titanium dioxide and resonant silicon nanoparticles to maximize perovskite solar cells’ efficiency.