The US National Renewable Energy Laboratory (NREL) has certified that a South Korean research team has achieved an efficiency rating of 25.73% with a perovskite PV cell based on alkyl ammonium chlorides. The master device built by the researchers achieved an efficiency of 26.08 percent.
“Alkylammonium chloride was used, which is dequantized in the crystallization step while combining with the perovskite components,” said researcher Sang Il Seok. “This optimal combination with alkyl was also able to optimally control the evaporation rate with the solvent during coating and heat treatment of the perovskite precursor solution.”
The scientists built the cell using a metal halide perovskite known as formamidinium lead iodide (FAPbI)3), which offers excellent thermal stability and a narrow bandgap. They claimed that the new process enables the creation of a dense perovskite film with good crystallinity. They studied the morphology of the membrane surface using wide-angle X-ray diffraction and scanning electron microscopy.
“RACl added to the precursor solution was believed to evaporate easily during coating and annealing,” they explained.
They tested the film in a perovskite cell and found that it had a power conversion efficiency of 26.08%, an open-circuit voltage of 1.18V, a short-circuit current of 25.7mA/cm2, and a duty cycle of 86.15%. Tested by NREL experts, the certified efficiency of the device was 25.73%.
The researchers presented the cell technique in the paper “Controlled Growth of Perovskite Layers by Volatile Alkylammonium Chlorides,” published recently Nature.
“This research is very relevant because it investigates the crystallization process of perovskite with halide anions in real time using the UNIST-PAL Beamline at the Pohang Accelerator Laboratory,” said researcher Tae Joo Shin.
