Italian researchers have used a titanium oxide sponge to successfully prevent lead leakage in a semi-transparent solar cell. The device has demonstrated comparable efficiency to semi-transparent perovskite devices, with an average visible transmittance (AVT) of 31.4%.
“We designed the solar cell for applications in building-integrated photovoltaics (BIPV) and agricultural electricity, where possible lead leakage can be considered a serious source of public environmental and health risk,” researcher Salvatore Valastro said. pv magazine.
TiO2, a highly adsorptive material, acts as an efficient electron transport layer (ETL) in perovskite solar cells. To address potential lead (Pb) leakage, the researchers created a solvent-free porous TiO2 film that formed a sponge-like structure capable of trapping Pb from damaged cells during simulated disasters.
“The TiO2 sponge can bind Pb at concentrations ranging from 24 g cm2 to 63 g cm2 contained in MAPbI3 layers with thicknesses of 200 nm (semi-transparent PSC) to 500 nm (opaque PSC), respectively,” the researchers explained.
They built the cell from a substrate made of glass and indium tin oxide (ITO), a hole transport layer (HTL) made of polytriarylamine (PTAA), a perovskite absorber with a TIO2 sponge, electron acceptor made of phenyl C61 butyric acid methyl ester (PCBM), bathocuproin (BCP) buffer layer, gold (Au) metal contact, and TIO2 sponge.
“We deposited the sponge using a physical solvent-free coating method using sputtering equipment, an easily scalable method widely used by semiconductor manufacturers,” Valastro said. “Before the coating process, a 1-minute prespray step is performed to clean the surface of the titanium target to remove oxidized layers.”
The solar cell’s power conversion efficiency was 11.6% and its average visible transmittance (AVT) is 31.4%. “An efficiency of 11.6% is characteristic of this semi-transparent architecture,” said Valastro.
The research team described the cell technology in the paper, “Suppressing Lead Leakage in Perovskite Solar Cells with a Durable Titanium Dioxide Sponge,” published recently The sustainability of nature.
“Our method represents a tangible step forward in reducing Pb emissions for BIPV, BAPV, agricultural electricity and opaque devices, and also paves the way for Pb recycling in end-of-life devices,” the team concluded.
