KAUST researchers have achieved 33.7% conversion efficiency for perovskite silicon tandem cell
Their use of a-cation THTZ-H+ during the manufacturing process exhibited higher efficiency compared to the cells manufactured without it
These laboratory results need to be now pursued with industrial cooperation before commercialization
Researchers at the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia found perovskite silicon tandem cells yielding higher performance and stability when tetrahydrotriazinium (THTZ-H+) was added to their manufacturing process. They have announced achieving a power conversion efficiency of 33.7% for such a cell with a 1-square-centimeter illuminated area.
According to the team led by KAUST Professor Stefaan De Wolf, the cells were tested in conditions that modeled the intense light and heat of the Arabian Peninsula. The structure with THTZ-H+ improved the device PCE and phase stability of 1.68 eV perovskites under prolonged light and heat exposure under 1-sun illumination at 85°C.
The tandem solar cells with THTZ-H+ showed more stability after 1,500 hours of testing compared with cells manufactured without THTZ-H+, as per KAUST.
The use of THTZ-H+ increased the number of hydrogen bonds in the crystal structure of perovskite films, which in turn improves the power conversion efficiency (PCE) and phase stability.
Now the team is seeking industry cooperation to commercialize perovskite silicon tandem cell manufacturing with THTZ-H+.
“Our laboratory efforts to reduce performance loss at less cost is scientific. These iterative improvements can have large industrial implications, but we need partners to show how to shift our findings to larger scale,” said De Wolf.
"Tetrahydrotriazinium had been a difficult molecule to synthesize and isolate until last year when a different research group showed the benefits of adding methylenediammonium chloride into the synthesis route," according to De Wolf’s team. According to them, the additive promoted the incorporation of tetrahydrotriazinium into the perovskite lattice.
Their research has been published in the Science scientific journal with the title Enhanced cation interaction in perovskites for efficient tandem solar cells with silicon.
In April 2023, De Wolf-led KAUST team had achieved 33.2% certified PCE for its monolithic perovskite-silicon tandem solar cells (see 33.2% Efficiency For Perovskite-Silicon Tandem Cells).