Title:
Spectral signatures of exciton-polarons in two-dimensional hybrid lead-halide perovskites

dc.contributor.advisor Silva, Carlos
dc.contributor.author Thouin, Felix
dc.contributor.committeeMember Mourigal, Martin
dc.contributor.committeeMember Trebino, Rick
dc.contributor.committeeMember First, Phillip N.
dc.contributor.committeeMember Brédas, Jean-Luc
dc.contributor.department Physics
dc.date.accessioned 2019-08-21T13:50:36Z
dc.date.available 2019-08-21T13:50:36Z
dc.date.created 2019-08
dc.date.issued 2019-07-18
dc.date.submitted August 2019
dc.date.updated 2019-08-21T13:50:36Z
dc.description.abstract This thesis investigates the optical properties of two-dimensional hybrid organic inorganic perovskites (2D-HOIPs). These materials, consisting of stacked layers of metal-halide octahedras separated by long organic cations, feature a previously unexplained excitonic fine-structure in their low-temperature absorption and emission spectra. This thesis work shows that features within this fine-structure correspond to exciton-polarons of distinct polaronic nature. The first evidence to support this interpretation was provided by successfully reproducing the low-temperature absorption spectrum using a modified Wannier formalism supposing distinct excitonic states with contrasting couplings to the lattice. This hypothesis is then unambiguously confirmed by high-resolution resonant impulsive coherent stimulated Raman spectroscopy which revealed in detail the exact polaronic nature of each excitons within this fine structure. Having shown their distinct polaronic nature, we then show that it drives the relaxation dynamics of photoexcited species down this excitonic manifold. This highlights the importance of the proper consideration of these polaronic effects when optimizing these materials for optoelectronics. We also show, using two-dimensional coherent spectroscopy, that these effects protect the excitons from many-body interactions with other quasiparticles hinting at the importance of polaronic effects in polaritonic microcavities based on these materials. Finally, we also observe stable biexcitons in these materials up to room temperature using high-power two-dimensional coherent spectroscopy showing the importance of many-body interactions in these materials. Our conclusions are of broad fundamental importance to this class of materials for they suggests an avenue to unify the physics governing spectrally broad and narrow emitting 2D-HOIPs. Moreover, due to the high degree of tunability of their crystalline structure, 2D-HOIPs offer an ideal system on which to test models that account for both strong electron-hole and strong electron-phonon interactions. This is of fundamental importance to all two-dimensional polar semiconductors.
dc.description.degree Ph.D.
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/61682
dc.language.iso en_US
dc.publisher Georgia Institute of Technology
dc.subject Two-dimensional perovskites
dc.subject Ultrafast spectroscopy
dc.subject Polarons
dc.subject Excitons
dc.subject Exciton-polarons
dc.title Spectral signatures of exciton-polarons in two-dimensional hybrid lead-halide perovskites
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Silva, Carlos
local.contributor.corporatename College of Sciences
local.contributor.corporatename School of Physics
relation.isAdvisorOfPublication 06529a19-e632-471a-8339-2c1dded3635a
relation.isOrgUnitOfPublication 85042be6-2d68-4e07-b384-e1f908fae48a
relation.isOrgUnitOfPublication 2ba39017-11f1-40f4-9bc5-66f17b8f1539
thesis.degree.level Doctoral
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