BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Chimie ParisTech - PSL - ECPv6.17.5//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:Chimie ParisTech - PSL
X-ORIGINAL-URL:https://www.chimieparistech.psl.eu
X-WR-CALDESC:Évènements pour Chimie ParisTech - PSL
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Europe/Paris
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20250330T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20251026T010000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20260329T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20261025T010000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20270328T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20271031T010000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260226T140000
DTEND;TZID=Europe/Paris:20260226T170000
DTSTAMP:20260219T171210Z
CREATED:20260219T171210Z
LAST-MODIFIED:20260219T171210Z
UID:29598-1772114400-1772125200@www.chimieparistech.psl.eu
SUMMARY:Séminaire Programme Gradué Chimie PSL
DESCRIPTION:Thursday February 26 at 2:00 pm (Paris time)\, Room Holweck\, building C\, 1st floor\, 10 rue Vauquelin\, ESPCI\, at LPEM in hybrid format: Electronic Structure of 2D Metal Halide Perovskites: Impact of Ligands on Octahedral Twists\, Energy Gaps and Exciton Binding Energy\, by Antoine Kahn\, Department of Electrical and Computer Engineering\, Princeton Univ.\, Princeton\, USA. Two-dimensional (2D) halide perovskites exhibit remarkable tunability of optoelectronic properties and good environmental stability achieved through the selection of both inorganic and organic constituents. In particular\, the incorporation of bifunctional ligands featuring non-ammonium terminus and functional groups capable of forming extra bonding motifs within the organic bilayer provides an effective strategy to engineer perovskite structures and introduce additional functionalities. This talk addresses the determination of optoelectronic properties\, i.e. single particle gap (EG) and exciton binding energy (EB)\, in several groups of Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) 2D metal halide perovskites via electron spectroscopy (UPS/IPES) aided by density functional theory (DFT). We first determine the electronic gap progression as a function of inorganic layer thickness in high purity films of BA2MAn-1PbnI3n+1 (n = 1-5).[1] By subtracting the optical from the electronic gap\, we show that EB vs. n ranges from 420 meV (n = 1) down to 100 meV (n = 5)\, well fitted by the empirical scaling law developed by Blancon et al.[2] We then turn to DJ and RP perovskites incorporating organic symmetric vs. asymmetric ligands (BDA vs. DMPD) and ligands with diverse functional groups (-CN\, -OH\, -COOH\, -Ph\, and -CH3)\, each exhibiting distinct bonding characteristics and dielectric properties\, and report on the impact of these ligands on the electronic and excitonic properties of these 2D perovskites.[3\,4] These bifunctional ligands featuring non-ammonium terminus and functional groups form extra bonding motifs within the organic bilayer and provide an effective strategy to engineer perovskite structures and introduce additional functionalities. Overall\, these results provide deeper insight into the complex impact of organic ligands on the electronic and excitonic properties of 2D perovskites\, in particular the substantial role of interlayer electronic coupling. [1]    X. Zhong et al.\, Adv. Energy Mater. 12\, 2202333 (2022)[2]    J.C. Blancon et al.\, Nat. Commun. 9\, 2254 (2018)[3]    S. Silver et al.\, Adv. Energy Mater. 10\, 1903900 (2020)[4]    X. Zhong et al.\, Adv. Energy Mater.\, 2304345 (2024)\nZoom link: https://espci.zoom.us/j/81264981490?pwd=pq3Pn4NKI0ZRl3ItvjN08t1bbCvLvD.1 ID: 812 6498 1490 Passcode: Becquerel
URL:https://www.chimieparistech.psl.eu/evenement-agenda/seminaire-programme-gradue-chimie-psl-185/
LOCATION:évènement hybride
CATEGORIES:Séminaire
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260226T140000
DTEND;TZID=Europe/Paris:20260226T170000
DTSTAMP:20260220T170436Z
CREATED:20260220T170436Z
LAST-MODIFIED:20260220T170436Z
UID:29601-1772114400-1772125200@www.chimieparistech.psl.eu
SUMMARY:Séminaire Programme Gradué Chimie PSL
DESCRIPTION:We will have the pleasure to host Mohammad RAEF (University of the Basque Country EHU\, Spain) for a SIMM seminar next week Thursday February 26 at 2 pm inSalle Nobélium (note the peculiar seminar room). The title of Mohammad’s talk is « Polylactide Stereocomplexation: Controlled Crystallization and Functionality in Soft Polymeric Materials« .\n\nPolylactide Stereocomplexation: Controlled Crystallization and Functionality in Soft Polymeric Materials\n\nPolylactide (PLA) stereocomplexation provides a robust route to engineer polymer properties through stereoselective interactions\, controlled crystallization\, and hierarchical self-assembly. The association of enantiomeric poly(L-lactide) and poly(D-lactide) chains leads to stereocomplex crystals with a distinct triclinic structure\, high packing density\, and melting temperatures approximately 50 K higher than those of conventional PLA homocrystals. These characteristics position stereocomplexed PLA as a model soft-matter system\, in which molecular structure and chain dynamics directly translate into macroscopic performance. In this seminar\, stereocomplexation is discussed as a kinetically governed crystallization process competing with homocrystallization\, rather than as a purely thermodynamic outcome. The influence of molecular weight\, chain entanglements\, processing history\, shear fields\, thermal protocols\, and interfacial interactions on stereocomplex formation is examined. Particular attention is given to how copolymerization\, selective nucleation\, and multifunctional fillers reshape the crystallization landscape\, enabling stereocomplex formation in high-molecular-weight and processing-relevant systems. Beyond enhanced thermal stability\, stereocomplex domains act as physical crosslinks and volume-excluding phases that strongly affect chain mobility\, mechanical reinforcement\, degradation kinetics\, and transport phenomena. These effects open extended application potential for stereocomplexed PLA in areas requiring dimensional stability\, heat resistance\, controlled degradability\, and multifunctionality\, including advanced packaging\, biomedical devices\, sustainable composites\, and functional soft materials. More broadly\, stereocomplexation offers design principles relevant to soft matter science\, linking confinement\, interfacial crystallization\, and multiscale structure–property relationships. By framing PLA stereocomplexation as a tunable platform for controlled crystallization\, this seminar highlights its relevance beyond biodegradable polymers\, with implications for the rational design of high-performance and sustainable polymeric materials.\n\nKeywords: Stereocomplexation\, polymer crystallization\, thermomechanical performance\, sustainable polymers\, structure-property relationship\n\nReference : Stereocomplexation: from molecular structure to functionality of advanced polylactide systems\, Polymer 2023\, https://doi.org/10.1016/j.polymer.2023.126066.
URL:https://www.chimieparistech.psl.eu/evenement-agenda/seminaire-programme-gradue-chimie-psl-186/
LOCATION:ESPCI Paris\, 10 Rue Vauquelin\, Paris\, 75005\, France
CATEGORIES:Séminaire
END:VEVENT
END:VCALENDAR