Expensive metals are widely used in commercial and laboratory solar cells. Screen printed silver (Ag) electrode is the standard metallization technique for the main stream Si solar cells due to its incredibly low electrical resistance. In 2021, It was report that silver accounts for about 10% of PV module costs. Due to the massive installation of PV panel over the past 20 years, the silver has averages an 9.31% year-on-year growth in prices. Perovskite solar cell is a new member in the PV family compared to the Si based device, but it has shown a jump on efficiency over past 10 years. Gold (Au) and silver (Ag) are generally used as electrode in perovskite devices to facilitate the transport of carrier from the solar cells to the outside circuit. Apart from the super high cost of using such metals, the metals are often a source of degradation phenomena in perovskite devices, resulting in poor stability. It has been found that the metal irons of the Au (Ag) electrode is able to penetrate the hole transport layers and produce deep traps and shunts. Also the migrated Ag+ can react with the perovskite absorber leading to the decline of cell efficiency. This suggests that regarding the current research status, metal-electrode based perovskite solar cells might not be able to achieve long-term device stabilities.
This project is going to investigate carbon-based electrode as an alternative to the metal-based electrode. The carbon-based electrode has been reported to be chemical stable with the perovskite absorber. Deposition of the carbon-based contact on top of the perovskite is one of the most promising routes to prolong the lifetime of a perovskite PV device. Carbon based electrode also has other advantages, including compatibility with up-scalable techniques, compatibility to flexible substrate due to the low temperature fabrication process.
In this project, we will find the approach of depositing commercialized carbon paste on smooth substrates, investigating the physical, mechanical and electrical properties of the carbon film. With success of fabricate the film, we will apply the electrode on solar cells with different structures, for example metal-oxide passivating contact for Si solar cells, Poly-Si based passivating contact for silicon solar cells and perovskite solar cells to study the performance of devices.