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Egyptian researchers have developed a new hole transport layer (HTL) for inverted perovskite solar cells using silver thiocyanate instead of the commonly used PEDOT:PSS and copper thiocyanate.
Researchers at the Central Metallurgical Research and Development Institute (CMRDI) in Egypt have fabricated an inverted perovskite solar cell with a new type of hole transport layer (HTM) based on silver thiocyanate (AgSCN). The scientists goal is to replace the most commonly used hole transport materials, such as PEDOT:PSS and copper thiocyanate (CuSCN), with AgSCN.
“The advantages of CuSCN are that it can serve as both a hole transport layer and a Cu doping source, whereas AgSCN, with its higher resistivity, can serve only as an Ag doping source with a faster diffusion rate. slow”, explain the scientists, who point out that AsSCN also transfers charges between the HTL and the perovskite layer better than PEDOT:PSS.
The group built the cell with an indium tin oxide (ITO) substrate, an electron transport layer (ETL) based on AgSCN, an absorber based on a type of lead halide perovskite known as methylammonium lead iodide. (MAPbI3), a phenyl-C61-butyric acid methyl ester (PCBM) layer, a bathocuproin (BCP) buffer layer, and a silver (Ag) metal contact.
The scholars deposited the AgSCN thin layer in a dry glove box at 25-30% relative humidity at least 30 minutes before the deposition of the perovskite layer began. Next, they deposited the perovskite layer on top of the HTL active layer by spin coating at 4,000 rpm for 30 seconds. The performance of the solar cell was compared to that of a reference device built with a PEDOT:PSS-based HTM.
The AgSCN-based device achieved a power conversion efficiency of 16.66%, an open circuit voltage of 1.14 mV, a short circuit current of 19.0 mA/cm2, and a fill factor of 77.1%. . The PEDOT:PSS cell achieved an efficiency of 15.11%, an open circuit voltage of 1.04 V, a short circuit current of 18.17 mA/cm2, and a fill factor of 80.37%.
“The successfully achieved AgSCN thin film produced a better quality perovskite film with free pinholes and large grains, while the PEDOT:PSS thin film produced a similar quality perovskite film with bare pinholes,” explained the group, noting that the AgSCN cell was also able to retain 80.9% of its initial efficiency after 500 hours in an atmosphere of 48% relative humidity.
“This low-cost, low-temperature AgSCN production method is considered easy and scalable, which bodes well for the commercialization of flexible devices and perovskite-based PV technologies,” the researchers concluded. “In short, AgSCN is a non-toxic, cheap and easy to work with at low temperatures rival. It is a strong contender for creating tandem devices and high-efficiency pin-junction solar cells made from perovskites.”
They described the cell technology in “ AgSCN as a new hole transporting material for inverted perovskite solar cells,” recently published in Scientific Reports . |
