May 6, 2024

Houston, We Have a Solution: Solar Cell Defects Healed by the Sun in the Vacuum of Space

The outcomes were just recently released in the journal Advanced Energy Materials.
Light-weight PSCs are a strong prospect for powering low-cost space hardware thanks to their low manufacturing expense, high performance and radiation solidity..
All previous proton irradiation research studies of PSCs took place on heavier substrates thicker than 1mm. Here, to benefit from high power-to-weight ratios, ultrathin radiation-resistant and optically transparent sapphire substrates of 0.175 mm were utilized by a group based at the University of Sydney. The task was led by Professor Anita Ho-Baillie, who is likewise an Associate Investigator with the ARC Centre of Excellence in Exciton Science.
The cells were exposed to fast scanning pencil beam of seven mega-electron-volts (MeV) protons using the high energy heavy ion microprobe at the Centre for Accelerator Science (CAS) at ANSTO, imitating the proton radiation exposure that the solar cell panels would go through while orbiting the earth on a satellite in low-earth orbit (LEO) for 10s to hundreds of years.
It was found that the type of cells including a popular HTM and a popular dopant within its HTM are less radiation tolerant than their competitors. The HTM in concern is the compound 2,2 ′,7,7 ′- Tetrakis [N,N-di( 4-methoxyphenyl) amino] -9,9 ′- spirobifluorene (Spiro-OMeTAD), while the dopant is lithium bis( trifluoromethanesulfonyl) imide (LiTFSI).
Through chemical analysis, the group found that fluorine diffusion from the LiTFSI caused by proton radiation introduces problems to the surface area of the perovskite photo-absorber, which could lead to cell degradation and efficiency losses over time.
” Thanks to the assistance offered by Exciton Science, we had the ability to obtain the deep-level transient spectroscopy capability to study the defect habits in the cells,” lead author Dr. Shi Tang stated.
The team had the ability to determine that cells without Spiro-OMeTAD and free of LiTFSI did not experience fluorine diffusion-related damage, and degradation brought on by proton-radiation might be reversed by heat treatment in vacuum. These radiation-resistant cells had either Poly [bis( 4-phenyl) (2,5,6-trimethylphenyl) (PTAA) or a mix of PTAA and 2,7-Dioctyl [1] benzothieno [3,2-b] [1] benzothiophene (C8BTBT) as the hole transport material, with tris( pentafluorophenyl) borane (TPFB) as the dopant.
” We hope that the insights created by this work will assist future efforts in establishing low-priced light-weight solar batteries for future space applications,” Professor Ho-Baillie stated.
Reference: “Effect of Hole Transport Materials and Their Dopants on the Stability and Recoverability of Perovskite Solar Cells on Very Thin Substrates after 7 MeV Proton Irradiation” by Shi Tang, Stefania Peracchi, Zeljko Pastuovic, Chwenhaw Liao, Alan Xu, Jueming Bing, Jianghui Zheng, Md Arafat Mahmud, Guoliang Wang, Edward Dominic Townsend-Medlock, Gregory J. Wilson, Girish Lakhwani, Ceri Brenner, David R. McKenzie and Anita W. Y. Ho-Baillie, 22 May 2023, Advanced Energy Materials.DOI: 10.1002/ aenm.202300506.

All previous proton irradiation research studies of PSCs took place on much heavier substrates thicker than 1mm. Here, to take advantage of high power-to-weight ratios, ultrathin radiation-resistant and optically transparent sapphire substrates of 0.175 mm were used by a group based at the University of Sydney. The task was led by Professor Anita Ho-Baillie, who is also an Associate Investigator with the ARC Centre of Excellence in Exciton Science.
It was found that the type of cells including a popular HTM and a popular dopant within its HTM are less radiation tolerant than their competitors. The team was able to determine that cells free of Spiro-OMeTAD and free of LiTFSI did not experience fluorine diffusion-related damage, and deterioration caused by proton-radiation might be reversed by heat treatment in vacuum.

Australian scientists have actually found that perovskite solar cells damaged by proton radiation can completely regain their efficiency by means of thermal vacuum annealing. The group achieved this task through the careful design of the hole transport product and the pioneering usage of novel spectroscopy strategies and ultrathin sapphire substrates.
Australian researchers have shown that perovskite solar cells harmed by proton radiation in low-earth orbit can recover their initial effectiveness in complete through annealing in a thermal vacuum.
The process is made possible by cautious style of the hole transportation product (HTM), an element that moves photo-generated favorable charges to the cells electrode.
This multidisciplinary task is pioneering in its usage of thermal admittance spectroscopy (TAS) and deep-level short-term spectroscopy (DLTS) to analyze flaws in proton-irradiated and thermal-vacuum recovered perovskite solar batteries (PSCs). The study is also the first to employ ultrathin sapphire substrates compatible with high power-to-weight ratios, rendering them appropriate for commercial applications.