BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Multi-scale dynamic disorder in halide perovskite solar cells - Pr
 of. Aron Walsh\, Imperial College London
DTSTART:20180419T131500Z
DTEND:20180419T141500Z
UID:TALK101935@talks.cam.ac.uk
CONTACT:Bartomeu Monserrat
DESCRIPTION:Perovskites are the wonder compounds of materials science\, wi
 th examples of magnets\, ferroelectrics\, superconductors\, ion conductors
 \, and most recently\, high-efficiency solar cells. This talk will address
  some of the chemical and physical properties that make halide perovskites
  unique. After six years of intensive research\, there has been a number o
 f breakthroughs in understanding\, but challenges and opportunities remain
 . \n\nTo understand the success of methylammonium lead iodide photovoltaic
 s\, we have been applying materials theory and simulation across multiple 
 length scales [1-5]. These organic-inorganic semiconductors satisfy the op
 toelectronic criteria for an active photovoltaic layer\, i.e. spectral res
 ponse in the visible range combined with light electron and hole effective
  masses. In addition\, these systems are structurally and compositionally 
 flexible with large dielectric constants\, and the ability to alloy on eac
 h of the lattice sites. \n\nI will discuss issues ranging from disorder as
 sociated with molecular vibrations and rotations within the inorganic netw
 ork\, to microscopic polarisation arising from correlations in cell dipole
  orientations. The temporal behaviour of hybrid perovskites has recently b
 een validated through a combination of neutron scattering\, time-resolved 
 vibrational spectroscopy\, and kinetic measurements of the current-voltage
  response. The implications for non-radiative electron-hole recombination 
 and new models for the cooling of hot carriers in operating solar cells wi
 ll be discussed. \n\n1. “Atomistic origins of high-performance in hybrid
  halide perovskite solar cells” Nano Letters\, 14\, 2584 (2014)\n2. “S
 elf-regulation mechanism for charged point defects in hybrid halide perovs
 kites” Angewandte Chemie Int. Ed. 54\, 1791 (2015)\n3. “Role of micros
 tructure in the electron–hole interaction of hybrid lead halide perovski
 tes” Nature Photonics 9\, 695 (2015)\n4. "Direct observation of dynamic 
 symmetry breaking above room temperature in methylammonium lead iodide per
 ovskite" ACS Energy Lett. 1\, 880 (2016)\n5. "Slow cooling of hot polarons
  in halide perovskite solar cells" ACS Energy Letters 2\, 2647 (2017)\n
LOCATION:TCM Seminar Room\, Cavendish Laboratory
END:VEVENT
END:VCALENDAR