On the Synthesis and Optical Characterization of Zero-Dimensional-Networked Perovskites

Handle URI:
http://hdl.handle.net/10754/623475
Title:
On the Synthesis and Optical Characterization of Zero-Dimensional-Networked Perovskites
Authors:
Almutlaq, Jawaher ( 0000-0003-4558-6773 )
Abstract:
The three-dimensional perovskites are known for their wide range of interesting properties including spectral tunability, charge carrier mobility, solution-based synthesis and many others. Such properties make them good candidates for photovoltaics and photodetectors. Low-dimensional perovskites, on the other hand, are good as light emitters due to the quantum confinement originating from their nanoparticle size. Another class of low-dimensional perovskites, also called low-dimensional-networked perovskites (L-DN), is recently reemerging. Those interesting materials combine the advantages of the nanocrystals and the stability of the bulk. For example, zero-dimensional-networked perovskite (0-DN), a special class of perovskites and the focus of this work, consists of building blocks of isolated lead-halide octahedra that could be synthesized into mm-size single crystal without losing their confinement. This thesis focuses on the synthesis and investigation of the optical properties of the 0-DN perovskites through experimental, theoretical and computational tools. The recent discovery of the retrograde solubility of the perovskites family (ABX3), the basis of the inverse temperature crystallization (ITC), inspired the reinvestigation of the low-dimensional-networked perovskites. The results of the optical characterization showed that the absorption and the corresponding PL spectra were successfully tuned to cover the visible spectrum from 410 nm for Cs4PbCl6, to 520 nm and 700 m for Cs4PbBr6 and Cs4PbI6, respectively. Interestingly, the exciton binding energies (Eb) of the 0-DNs were found to be in the order of few hundred meV(s), at least five times larger than their three-dimensional counterpart. Such high Eb is coupled with a few nanoseconds lifetime and ultimately yielded a high photoluminesce quantum yield (PLQY). In fact, the PLQY of Cs4PbBr6 powder showed a record of 45%, setting a new benchmark for solid-state luminescent perovskites. Computational methods were used to calculate the bandgap and study the corresponding excitonic behavior. However, the unexpected mismatch between the calculated and experimental bandgaps questions the origin of the high luminescence, which to date, remains an area of scientific debate that needs further study. Until then, the high PLQY, together with the spectral tunability, insensitivity to particle size and stability all offer a new avenue for more sustainability in light-emitting materials
Advisors:
Bakr, Osman M. ( 0000-0002-3428-1002 )
Committee Member:
Abdelsaboor, Omar F. M. ( 0000-0001-8500-1130 ) ; Li, Lain-Jong ( 0000-0002-4059-7783 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Materials Science and Engineering
Issue Date:
26-Apr-2017
Type:
Thesis
Appears in Collections:
Theses

Full metadata record

DC FieldValue Language
dc.contributor.advisorBakr, Osman M.en
dc.contributor.authorAlmutlaq, Jawaheren
dc.date.accessioned2017-05-11T12:06:36Z-
dc.date.available2017-05-11T12:06:36Z-
dc.date.issued2017-04-26-
dc.identifier.urihttp://hdl.handle.net/10754/623475-
dc.description.abstractThe three-dimensional perovskites are known for their wide range of interesting properties including spectral tunability, charge carrier mobility, solution-based synthesis and many others. Such properties make them good candidates for photovoltaics and photodetectors. Low-dimensional perovskites, on the other hand, are good as light emitters due to the quantum confinement originating from their nanoparticle size. Another class of low-dimensional perovskites, also called low-dimensional-networked perovskites (L-DN), is recently reemerging. Those interesting materials combine the advantages of the nanocrystals and the stability of the bulk. For example, zero-dimensional-networked perovskite (0-DN), a special class of perovskites and the focus of this work, consists of building blocks of isolated lead-halide octahedra that could be synthesized into mm-size single crystal without losing their confinement. This thesis focuses on the synthesis and investigation of the optical properties of the 0-DN perovskites through experimental, theoretical and computational tools. The recent discovery of the retrograde solubility of the perovskites family (ABX3), the basis of the inverse temperature crystallization (ITC), inspired the reinvestigation of the low-dimensional-networked perovskites. The results of the optical characterization showed that the absorption and the corresponding PL spectra were successfully tuned to cover the visible spectrum from 410 nm for Cs4PbCl6, to 520 nm and 700 m for Cs4PbBr6 and Cs4PbI6, respectively. Interestingly, the exciton binding energies (Eb) of the 0-DNs were found to be in the order of few hundred meV(s), at least five times larger than their three-dimensional counterpart. Such high Eb is coupled with a few nanoseconds lifetime and ultimately yielded a high photoluminesce quantum yield (PLQY). In fact, the PLQY of Cs4PbBr6 powder showed a record of 45%, setting a new benchmark for solid-state luminescent perovskites. Computational methods were used to calculate the bandgap and study the corresponding excitonic behavior. However, the unexpected mismatch between the calculated and experimental bandgaps questions the origin of the high luminescence, which to date, remains an area of scientific debate that needs further study. Until then, the high PLQY, together with the spectral tunability, insensitivity to particle size and stability all offer a new avenue for more sustainability in light-emitting materialsen
dc.language.isoenen
dc.subjectZero-Dimensional-Networkeden
dc.subjectPerovskitesen
dc.subjectCs4PbBr6en
dc.subjectCs4PbI6en
dc.subjectCs4PbCl6en
dc.titleOn the Synthesis and Optical Characterization of Zero-Dimensional-Networked Perovskitesen
dc.typeThesisen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberAbdelsaboor, Omar F. M.en
dc.contributor.committeememberLi, Lain-Jongen
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.nameMaster of Scienceen
dc.person.id133651en
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