Banca de QUALIFICAÇÃO: NONSO LIVINUS OKOLI

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : NONSO LIVINUS OKOLI
Data: 06/10/2026
HORA: 14:00
LOCAL: Híbrida – SA
TÍTULO:

 Development of Naphthalenediimide-Based Electron Transport Layers for Perovskite Solar Cells

PÁGINAS: 124
RESUMO:

The growing global demand for energy and the need to reduce dependence on fossil fuels have increased interest in photovoltaic technologies as a sustainable source of electricity. Improving photovoltaic devices requires not only suitable light-absorbing materials but also efficient charge-transport layers and well-engineered interfaces, where organic molecules offer tunable electronic and interfacial properties. Naphthalenediimide (NDI) derivatives are promising for these roles because of their electron-accepting character. This thesis investigates thin films of silane-functionalized naphthalenediimide (SNDI), a material recently developed at UFABC. The silane group confers potential for molecular anchoring and network formation for electron transport, through hydrolysis and condensation processes. The properties of SNDI may be particularly relevant to organic–inorganic hybrid perovskite solar cells (PSCs), which offer favourable optoelectronic properties but remain limited by charge recombination, interfacial defects, and electron-transport losses. The resulting Si–O–Si bond formation can act as a passivation layer in these devices, protecting them against the deleterious effects of moisture, while the coupling of the molecules' aromatic groups should enable optimized electron transport. Spin-coated and drop-cast pristine and hydrolyzed SNDI films were studied, using toluene and tetrahydrofuran (THF) as solvents, to understand the material's basic properties. The effects of silane hydrolysis and processing conditions on the structural, morphological, optical, wettability, and electrochemical properties of the resulting films were evaluated using UV–Vis, contact-angle, AFM, electrochemical impedance, XRD, and Williamson–Hall analyses. Hydrolysis facilitated film formation and produced denser, more crosslinked SNDI films. These films exhibited significantly different electrochemical behavior compared to non-hydrolyzed films. Cyclic voltammetry revealed restricted redox kinetics in the hydrolyzed films, consistent with limited ionic diffusion through the denser structure. Impedance spectroscopy showed slightly better interfacial charge-transfer kinetics in the hydrolyzed films. Non-hydrolysed SNDI films were subsequently investigated as an interfacial layer on compact/mesoporous TiO2, the standard ETL of n-i-p PSC devices, and also as a single ETL layer. Incorporation of the SNDI layer resulted in an increase in crystallite size of the subsequently deposited perovskite films. Preliminary results in n-i-p PSC devices showed a favorable photovoltaic response under some processing conditions, although the unmodified TiO2 reference still produced higher photocurrent, indicating the need for further process optimization. Taken together, these findings demonstrate the potential of SNDI for TiO2/perovskite interface engineering and provide a basis for further optimization of its processing conditions, charge-transport properties, and device performance.

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 - 1762438 - JEAN JACQUES BONVENT
Membro Titular - Examinador(a) Externo ao Programa - 2604737 - EVERALDO CARLOS VENANCIO
Membro Suplente - Examinador(a) Interno ao Programa - 2605463 - JOSE ANTONIO SOUZA
Membro Suplente - Examinador(a) Interno ao Programa - 1545738 - MARCIA TSUYAMA ESCOTE
Membro Suplente - Examinador(a) Interno ao Programa - 1707133 - ISELI LOURENCO NANTES
Membro Suplente - Examinador(a) Externo ao Programa - 2604128 - ALEXANDRE JOSE DE CASTRO LANFREDI