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    From ScienceDaily@1:317/3 to All on Tuesday, May 03, 2022 22:30:40
    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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