Korean researchers from UNIST have set a new world-record efficiency performance of 22.1 % in small perovskite solar cells and 19.7 percent in 1-square-centimeter cells.
The new efficiency record was achieved when the researchers made use of a new technique to produce inorganic-organic hybrid perovskite solar cells (PSCs).
This breakthrough comes from a research, conducted by Distinguished Professor Sang-Il Seok of Energy and Chemical Engineering at UNIST in collaboration with Professor Jun Hong Noh of Korea Research Institute of Chemical Technology and Professor Eun Kyu Kim of Hanyang University who both partook as co-authors of the study.
A key feature of this technology is its ability to fix the dominating defect in perovskite-halides, which is known to decrease the photoelectric efficiency.
According to the research team, the careful control of the growth conditions of perovskite layers with management of deficient halide anions is essential for realizing high-efficiency thin-film PSCs based on lead-halide-perovskite absorbers.
“This study can improve the current record efficiency of perovskite solar cells from 20.1% to 22.1%,” says Professor Seok. “This will accelerate the commercialization of the low-cost, high-performance perovskite solar cells.”
An organic-inorganic hybrid PSC is a type of solar cell, which includes the perovskite structured compound, as the light-harvesting active layer. Such devices have inspired much research interest owing to their applications in high-efficiency solar cells and light emission.
Moreover these solar cells not only show relatively high photovoltaic energy conversion efficiencies (above 22%), but can be also easily fabricated using cheap inorganic-organic perovskite compounds.
In their study, the research team demonstrated the introduction of additional iodide ions into the organic cation solution, which are used to form the perovskite layers through an intramolecular exchanging process, decreases the concentration of deep-level defects.
The end result showed that the defect-engineered thin perovskite layers enable the fabrication of PSCs with a NREL certified power conversion efficiency of 22.1% in small cells and 19.7% in 1-square-centimeter cells.
Image credits and content: UNIST