Banca de QUALIFICAÇÃO: LEONARDO JOSÉ QUINTERO DA CUNA
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : LEONARDO JOSÉ QUINTERO DA CUNA
DATA : 10/12/2024
HORA: 14:00
LOCAL: Sala 406 do Bloco B do Campus de Santo André da Universidade Federal do ABC
TÍTULO:
Synthesis and Physical PropertieStudy of Hybrid Perovskites and Vanadium Oxides for Energy Applications
PÁGINAS: 70
RESUMO:
The study and development of advanced semiconducting materials for applications in renovable energy is of great importance in condensed matter field. Here, we have studied both halide perovskites and vanadate oxides. We have synthesized 2D Ruddlesden-Popper (BA)2MAn-1PbnI3n+1 samples using n-butylamine (BA) molecule as a spacer with n = 1, 2, 3, and 6, and also the corresponding 3D counterpart MAPbI3 (MA= CH3NH3) for a comparative study. We have performed a comprehensive study involving electrical transport and photoconductivity effect as a function of the particle’s organization: parallel, perpendicular, and disordered orientation to the electrodes. We have observed that for intermediary value of n, the 2D layered particles are aligned perpendicular to the electrode and parallel to the transport electrical current. A distinct and complex S-shape behavior in V-i curves is disclosed, suggesting two electrical resistance regimes. The sharp increase in resistance suggests the presence of electronic barriers for all samples, which is suppressed for columnar arrays of n = 2 and 3 under illumination. We suggest that this linear behavior in the photoconductivity effect is close related to the absence of electrical barriers at the interface of the particles due to perpendicular alignment to the electrodes. The absence of interfaces in a more columnar array facilitates ionic conductivity enhancing photoelectric effect. We have also performed a comprehensive experimental and theoretical study on the interaction between all-inorganic perovskite CsPb(Br,I)3 quantum dots (QDs) with Ag metallic nanoparticles (AgNPs). An interfacial charge transfer process associated with exciton dynamic between CsPb(Br,I)3 nanocrystals and metallic nanoparticles has been studied. We have observed a strong PL quenching when AgNPsare placed on the surface of CsPb(Br,I)3 nanocrystals suggesting charge transfer process. To enhance the stability of QDs for practical applications, thin films of CsPbBr3 coated with TEOS were developed, demonstrating notable resistance in water for up to 20 minutes. Additionally, BiVO4 thin films—a semiconductor widely used in the study of the oxygen evolution reaction in water splitting—were investigated. When coated with AgNPs, these films showed a significant improvement in photoelectrochemical activity, indicating that the heterostructure formation may enhance performance in clean energy generation applications.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1671688 - ANDRE SARTO POLO
Membro Titular - Examinador(a) Interno ao Programa - 2249395 - THIAGO BRANQUINHO DE QUEIROZ
Membro Titular - Examinador(a) Externo ao Programa - 1671599 - MARCOS DE ABREU AVILA
Membro Titular - Examinador(a) Externo ao Programa - 3420345 - CARLOS AUGUSTO MERA ACOSTA
Membro Suplente - Examinador(a) Interno ao Programa - 1676364 - JULIANA MARCHI
Membro Suplente - Examinador(a) Interno ao Programa - 1309493 - PEDRO ALVES DA SILVA AUTRETO
Membro Suplente - Examinador(a) Interno ao Programa - 1544341 - WENDEL ANDRADE ALVES
Membro Suplente - Examinador(a) Externo ao Programa - 3066318 - JULIAN ANDRES MUNEVAR CAGIGAS