BEGIN:VCALENDAR
VERSION:2.0
METHOD:PUBLISH
CALSCALE:GREGORIAN
PRODID:-//WordPress - MECv7.34.2//EN
X-ORIGINAL-URL:https://majulab-su-mirror.lkb.upmc.fr/
X-WR-CALNAME:MajuLab
X-WR-CALDESC:
X-WR-TIMEZONE:Europe/Paris
BEGIN:VTIMEZONE
TZID:Europe/Paris
X-LIC-LOCATION:Europe/Paris
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20260329T030000
RRULE:FREQ=YEARLY;BYMONTH=03;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20261025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=4SU
END:STANDARD
END:VTIMEZONE
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-PUBLISHED-TTL:PT1H
X-MS-OLK-FORCEINSPECTOROPEN:TRUE
BEGIN:VEVENT
CLASS:PUBLIC
UID:MEC-58e4d44e550d0f7ee0a23d6b02d9b0db@majulab-su-mirror.lkb.upmc.fr
DTSTART;TZID=Europe/Paris:20230106T093000
DTEND;TZID=Europe/Paris:20230106T113000
DTSTAMP:20230105T151827Z
CREATED:20230105
LAST-MODIFIED:20230105
PRIORITY:5
SEQUENCE:1
TRANSP:OPAQUE
SUMMARY:PhD thesis defense  of Mohamed-Raouf Amara
DESCRIPTION:Optical spectroscopy of single perovskite nanocrystals for quantum photonics\nLead halide perovskites (LHPs) in their nanocrystal (NC) form have recently emerged as efficient quantum light emitters despite their low-temperature colloidalsynthesis and the structural lability of the perovskite lattice. This has led to an intense debate about the nature of the excitonic states at the origin of the emissionof photons. In particular, the nature of the band-edge exciton states and the bright or dark character of the lowest energy exciton state remain open questions.While symmetry arguments predict a lowest-lying dark exciton state, it was hypothesised that the combination of strong-spin orbit and structural instability shouldlead to a Rashba effect which places the bright exciton state below the dark exciton, in contrast with all other established materials.\nThis work is a detailed study, both in the spectral and time domain, of single CsPbBr₃ NCs. To do so, experimental platforms for the synthesis and optical characterisation at the singe object level were put in place by the author both at NTU and LPENS.\nThanks to detailed spectral analysis of the emission, the full spectral fingerprint of single CsPbBr₃ NCs, comprised of a bright triplet exciton, trion and biexcitoneach with its own set of optical phonon replica, is revealed across a wide range of NCs sizes from ∼7 nm to ∼20 nm. The fast emission of single CsPbBr₃ NCs atthe lowest cryogenic temperatures is investigated in detail and put in perspective with the decay times across LHPs. In addition, in light of the debate about theexciton fine structure ordering in CsPbBr₃, we report on experiments to probe the dark exciton state via both magneto-optical and temperature-dependentphotoluminescence decay measurements.\nWhile these measurements do not directly evidence a spectral fingerprint for the dark exciton, they enable us to gain insight into the population redistribution mechanisms at play in setting the populations of the exciton fine structure states. Thus, thanks to a combination of spectral and temporal analysis of the emission of single CsPbBr₃ NCs, critical information about the band-edge exciton fine structure is obtained.\nThis work should help the community refine theoretical models and converge towards an accurate description of the band-edge exciton of these fledgling materials, thus helping to shed light onto the oustanding properties of LHPs.\n \n\nTo attend click on the link below:\nMicrosoft Team link ( https://teams.microsoft.com/l/meetup-join/19%3ameeting_MGJhMGNlYWMtMjQyYy00N2QyLWEyZWUtYjU4YmNhNTBlMjhh%40thread.v2/0?context=%7b%22Tid%22%3a%2215ce9348-be2a-462b-8fc0-e1765a9b204a%22%2c%22Oid%22%3a%22c987aff2-e49a-4fba-9125-a278e3fc44fa%22%7d )\n
URL:https://majulab-su-mirror.lkb.upmc.fr/events/phd-thesis-defense-of-mohamed-raouf-amara/
CATEGORIES:Seminar
END:VEVENT
END:VCALENDAR