Banca de QUALIFICAÇÃO: ARIANY BONADIO
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : ARIANY BONADIO
DATA : 03/03/2020
HORA: 14:00
LOCAL: sala 303, 3º andar, Bloco B, Campus SA da Fundação Universidade Federal do ABC, localizada na Avenida dos Estados, 5001, Santa Terezinha, Santo André, SP
TÍTULO:
Synthesis and Physical Properties Characterizations of Hybrid CH3NH3PbI3 perovskites
PÁGINAS: 60
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
SUBÁREA: Física da Matéria Condensada
RESUMO:
Methylammonium lead iodide (CH3NH3PbI3) has been attracted great attention from scientific community due to its excellent photovoltaic performance. This compound with a perovskite-like crystal structure can be used as light-harvesting layer in solar cell architectures with efficiency close to silicon solar cells. In this work, we have synthesized lead halide perovskites and studied their stability, structural, morphological, and optical properties which have attracted a great interest on perovskite solar cells due to their high efficiency and ability to tune in the bandgap energy. We have observed the formation of microcuboid morphology for CH3NH3PbI3 samples and microwires for CsPbI3 via solvothermal method. We have used lead iodide, methylamine or cesium acetate as precursors and hydroiodic acid in isopropyl alcohol solution. We have systematically changed the solution temperature and PbI2 concentration during the synthesis process. We have observed that CH3NH3PbI3 morphology is synthesis parameter dependent chaging from small irregular particles to very regular polyhedral shape. We have also observed the presence of hopper-type morphology which also depends on synthesis parameter. We have also shown that a monohydrated crystal phase (CH3NH3·H2O)PbI3 is formed when CH3NH3PbI3 is exposed to a certain amount of water. We have found microcubes turning into a 1D very long microwires with monoclinic structural phase. The monohydrate compounds have a monoclinic structure with 1D chains of [PbI6]4- octahedra. The 1D chains are formed by the iodide ions shared by the edges of the [PbI6]4- ions and are stabilized by the presence of both water and CH3NH3+, forming big channels between chains. This monohydrate compound can easily be reversed to CH3NH3PbI3 through heat treatment or in evacuated atmosphere eliminating the water present in the channels of the structure. We have taken advantage of those formed big channels to introduce magnetic ions into the perovskite structure. The morphological and structural properties of this system were studied through SEM microscope, X-ray diffraction and FT-IR. Electric transport and Magntic characterizations were also carried out to study the influence of magnetic ions on the crystal lattice and charge carrier dynamics.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1707133 - ISELI LOURENCO NANTES CARDOSO
Membro Titular - Examinador(a) Interno ao Programa - 1671275 - DERVAL DOS SANTOS ROSA
Membro Titular - Examinador(a) Interno ao Programa - 1600858 - HERCULANO DA SILVA MARTINHO
Membro Titular - Examinador(a) Externo ao Programa - 1305186 - SERGIO BROCHSZTAIN
Membro Suplente - Examinador(a) Interno ao Programa - 2946001 - ANTONIO ALVARO RANHA NEVES
Membro Suplente - Examinador(a) Interno ao Programa - 1763443 - MARCIA APARECIDA DA SILVA SPINACE
Membro Suplente - Examinador(a) Interno ao Programa - 1734908 - FABIO FURLAN FERREIRA
Membro Suplente - Examinador(a) Externo ao Programa - 2249395 - THIAGO BRANQUINHO DE QUEIROZ