MSGID: 1:317/3 62720190   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
   applications    
    This new protocol for testing perovskite solar cells paves the way for   
   their use in powering objects that require the cells' radiation hardness and   
   durability.    
      
     Date:   
         May 3, 2022   
     Source:   
         University of Oklahoma   
     Summary:   
         Researchers have described the optimal conditions for testing   
         perovskite solar cells for space.   
      
      
      
   FULL STORY   
   ==========================================================================   
   Researchers at the University of Oklahoma, with the National Renewable   
   Energy Laboratory, the University of North Texas, the NASA Glenn Research   
   Center and several collaborators within the space power community,   
   have recently published a paper in the journal Joulethat describes the   
   optimal conditions for testing perovskite solar cells for space.   
      
      
   ==========================================================================   
   Perovskites are a material used in a type of solar cell, which are devices   
   that convert light into electrical energy. Ian Sellers, a physicist at   
   the University of Oklahoma and a co-author of the paper, said perovskite   
   solar cells are creating excitement in the photovoltaics community due   
   to their rapidly increasing performance and their high tolerance to   
   radiation that suggests they could be used to provide power for space   
   satellites and spacecrafts.   
      
   Sellers, who is also the Ted S. Webb Presidential Professor in the   
   Homer L.   
      
   Dodge Department of Physics and Astronomy in the Dodge Family College   
   of Arts and Sciences, and the associate director of the Oklahoma   
   Photovoltaics Research Institute, has mentored multiple graduate students   
   and a postdoctoral researcher in this field. The former postdoctoral   
   researcher in Seller's lab, Brandon Durant, is now a National Research   
   Council Fellow residing at the U.S.   
      
   Naval Research Laboratory and is one of the co-authors of the paper.   
      
   "Perovskites are exciting to a lot of people in the photovoltaics   
   community because this new solar cell material can reach high efficiencies   
   and has done so quickly and relatively simply," Sellers said. "But these   
   materials also have significant issues in terms of stability and yield,   
   particularly in atmospheric conditions -- moisture, oxygen degrades   
   this material, so it was interesting that there were a few people who   
   suggested that despite these terrestrial instability issues, this system   
   appeared radiation hard and appropriate for space."  "The term 'radiation   
   hard' is used by researchers to describe how much damage occurs in an   
   object or device when it is a space environment," said Joseph Luther,   
   a senior scientist on the chemical materials and nanoscience team at   
   the National Renewable Energy Laboratory. "It's interesting, especially   
   with perovskite materials, because the semiconductors are known to be   
   soft, however radiation hardness just means that they can tolerate the   
   radiation induced defects without a rapid degradation in performance."   
   The problem the team from OU, NREL and the University of North Texas set   
   out to solve was how applicable standard space testing of solar cells   
   are for the perovskites.   
      
      
      
   ==========================================================================   
   "What we found was that perovskites are radiation hard but not for the   
   reasons many believed," Sellers said. "We found that the community in   
   general is not testing them properly. Perovskites are thin films, and   
   they are also very soft, so if you use the space protocols developed   
   for traditional solar cells, the interaction of high-energy particles   
   is negligible, meaning perovskites looked radiation hard because   
   they weren't, in our opinion, being tested properly."  To develop a   
   new way to test the perovskites, Durant worked with Bibhudutta Rout,   
   an associate professor in the Department of Physics at UNT in Denton,   
   Texas, to measure the solar cells' radiation hardness under different   
   conditions or radiation exposure.   
      
   "We started doing these very targeted radiation dependence tests by   
   controllably stopping these particles in different parts of the solar   
   cell," Sellers said. "So rather than using very high-energy particles,   
   we were using lower-energy particles, specifically protons, since these   
   are more harmful for the perovskites and are very prevalent in space,   
   bombarding solar cells and other materials in space at low energies. When   
   we did this, we confirmed that perovskites indeed are very radiation hard   
   because they're soft and they're not very dense, so when they're damaged,   
   they heal quickly."  Sellers compares the effect to a tub of water. The   
   water starts out as still.   
      
   You can splash the water to create chaos, but it will go back to stillness   
   once the splashing stops.   
      
   "These perovskites are very close to being like a liquid, so when they're   
   damaged, they self-heal," he said. "Perovskites, like a tub of water,   
   will be disordered and damaged in space, but will also very quickly settle   
   or heal and go back to normal. What we've done is to create a protocol,   
   a set of conditions that perovskite cells must be tested at before they   
   go into space, so that the global community is testing these materials   
   properly and in the same way."  Applications for this research opens   
   an array of possibilities. One area of research interest includes the   
   investigation of perovskites' use in permanent installations on the moon,   
   specifically in whether lightweight flexible perovskites could be sent   
   into space folded up and successfully deployed there, or even made on   
   the moon.   
      
   Likewise, future research could explore the utility of perovskite solar   
   cells for space missions to planets like Jupiter that have an intense   
   radiation environment or for satellite missions in polar orbits with   
   high radiation levels.   
      
   "Space qualification of a new material is driven by mission   
   requirements," said NASA Glenn Research engineer and co-author, Lyndsey   
   McMillon-Brown. "This work is so important because we're probing the   
   perovskites' response to radiation most relevant to the applications NASA   
   is most interested in."  "By coming together and defining some protocols   
   that the federal and the commercial space community have agreed with   
   on the way these should be tested is a significant step forward that is   
   pioneering for how perovskites could be deployed in space," Sellers said.   
      
      
   ==========================================================================   
   Story Source: Materials provided by University_of_Oklahoma. Note:   
   Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Ahmad R. Kirmani, Brandon K. Durant, Jonathan Grandidier, Nancy M.   
      
         Haegel, Michael D. Kelzenberg, Yao M. Lao, Michael D. McGehee,   
         Lyndsey McMillon-Brown, David P. Ostrowski, Timothy J. Peshek,   
         Bibhudutta Rout, Ian R. Sellers, Mark Steger, Don Walker, David   
         M. Wilt, Kaitlyn T.   
      
         VanSant, Joseph M. Luther. Countdown to perovskite space   
         launch: Guidelines to performing relevant radiation-hardness   
         experiments. Joule, 2022; DOI: 10.1016/j.joule.2022.03.004   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220503141409.htm   
      
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