Hybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coating

Handle URI:
http://hdl.handle.net/10754/627190
Title:
Hybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coating
Authors:
Munir, Rahim ( 0000-0002-6029-3760 )
Abstract:
Our reliance on semiconductors is on the rise with the ever growing use of electronics in our daily life. Organic-inorganic hybrid lead halide perovskites have emerged as a prime alternative to current standard and expensive semiconductors because of its use of abundant elements and the ease of solution processing. This thesis has shed light on the ink-to-solid conversion during the one-step solution process of hybrid perovskite formulations from DMF. We utilize a suite of in situ diagnostic probes including high speed optical microscopy, optical reflectance and absorbance, and grazing incidence wide angle x-ray scattering (GIWAXS), all performed during spin coating, to monitor the solution thinning behavior, changes in optical absorbance, and nucleation and growth of crystalline phases of the precursor and perovskite. The starting formulation experiences solvent-solute interactions within seconds of casting, leading to the formation of a wet gel with nanoscale features visible by in situ GIWAXS. The wet gel subsequently gives way to the formation of ordered precursor solvates (equimolar iodide and chloride solutions) or disordered precursor solvates (equimolar bromide or 3:1 chloride), depending upon the halide and MAI content. The ordered precursor solute phases are stable and retain the solvent for long durations, resulting in consistent conversion behavior to the perovskite phase and solar-cell performance. In this thesis, we develop a firm understanding of the solvent engineering process in which an anti-solvent is used during the coating process through the solvent mixture of GBL and DMSO in different ratios. It has been shown that solvent engineering produce pin hole-free films, justifying its wide adoption across the field. We then translate our learnings from the lab scale spin coating process to the industrial friendly blade coating process. Here we compare the ink solidification and film formation mechanisms of CH3NH3PbI3 in solutions we used to understand the key scientific insights through spin coating. We observe high-quality film formation for T > 100oC, namely in conditions which inhibit the formation of the crystalline intermediate complex phases. In doing so, we achieve fast and direct formation of the perovskite phase with solar cells yielding PCE > 17%.
Advisors:
Amassian, Aram ( 0000-0002-5734-1194 )
Committee Member:
Laquai, Frédéric ( 0000-0002-5887-6158 ) ; Han, Yu ( 0000-0003-1462-1118 ) ; Unger, Eva L.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Materials Science and Engineering
Issue Date:
22-Nov-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorAmassian, Aramen
dc.contributor.authorMunir, Rahimen
dc.date.accessioned2018-02-25T10:18:47Z-
dc.date.available2018-02-25T10:18:47Z-
dc.date.issued2017-11-22-
dc.identifier.urihttp://hdl.handle.net/10754/627190-
dc.description.abstractOur reliance on semiconductors is on the rise with the ever growing use of electronics in our daily life. Organic-inorganic hybrid lead halide perovskites have emerged as a prime alternative to current standard and expensive semiconductors because of its use of abundant elements and the ease of solution processing. This thesis has shed light on the ink-to-solid conversion during the one-step solution process of hybrid perovskite formulations from DMF. We utilize a suite of in situ diagnostic probes including high speed optical microscopy, optical reflectance and absorbance, and grazing incidence wide angle x-ray scattering (GIWAXS), all performed during spin coating, to monitor the solution thinning behavior, changes in optical absorbance, and nucleation and growth of crystalline phases of the precursor and perovskite. The starting formulation experiences solvent-solute interactions within seconds of casting, leading to the formation of a wet gel with nanoscale features visible by in situ GIWAXS. The wet gel subsequently gives way to the formation of ordered precursor solvates (equimolar iodide and chloride solutions) or disordered precursor solvates (equimolar bromide or 3:1 chloride), depending upon the halide and MAI content. The ordered precursor solute phases are stable and retain the solvent for long durations, resulting in consistent conversion behavior to the perovskite phase and solar-cell performance. In this thesis, we develop a firm understanding of the solvent engineering process in which an anti-solvent is used during the coating process through the solvent mixture of GBL and DMSO in different ratios. It has been shown that solvent engineering produce pin hole-free films, justifying its wide adoption across the field. We then translate our learnings from the lab scale spin coating process to the industrial friendly blade coating process. Here we compare the ink solidification and film formation mechanisms of CH3NH3PbI3 in solutions we used to understand the key scientific insights through spin coating. We observe high-quality film formation for T > 100oC, namely in conditions which inhibit the formation of the crystalline intermediate complex phases. In doing so, we achieve fast and direct formation of the perovskite phase with solar cells yielding PCE > 17%.en
dc.language.isoenen
dc.subjectPerovskiteen
dc.subjectSolar cellen
dc.subjectGIWAXSen
dc.subjectIn-situ measurementsen
dc.titleHybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coatingen
dc.typeDissertationen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberLaquai, Frédéricen
dc.contributor.committeememberHan, Yuen
dc.contributor.committeememberUnger, Eva L.en
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id124287en
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