Banca de QUALIFICAÇÃO: RAYLA NGILA TAVEIRA DE BRITO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAYLA NGILA TAVEIRA DE BRITO
DATE: 30/04/2026
TIME: 10:00
LOCAL: Auditório do LABTAM
TITLE:

Effect of A-Site and B-Site Doping on the Structural and Optical Properties of CsPbI₃ Perovskite for Photovoltaic Applications.

KEY WORDS:

CsPbI3 perovskite; doping; structural properties; optical properties; solar cell

PAGES: 77
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

The fully inorganic perovskite CsPbI3 has emerged as a promising material for photovoltaic applications due to its high absorption coefficient and suitable band gap; however, its structural instability under ambient conditions remains a major limitation for practical use. In this work, the influence of A- and B-site doping on the structural and optical properties of CsPbI3 was investigated with a view to photovoltaic applications. Doping with K+ and Rb+ at the A site and Sb3+ at the B site was evaluated for compositions previously defined with the aid of Density Functional Theory (DFT) calculations. The samples were synthesized and characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, SEM, and, for the most promising composition, applied in a photovoltaic device. The results showed that the nature of the dopant directly influences the incorporation mechanism and the structural modifications of the crystal lattice. For K+, evidence of interstitial incorporation associated with lattice expansion was observed, whereas for Rb+, the main hypothesis was substitutional incorporation, with a possible coexistence of substitutional and interstitial mechanisms at higher concentration. For Sb3+, a more complex structural behavior was proposed, related to simultaneous effects of lattice contraction and expansion. From the optical point of view, the I_Sb0.125 composition stood out for exhibiting a broader absorption range and the greatest experimental band gap reduction (1,8798 eV). Based on these results, this sample was selected as the photoactive layer for the fabrication of a solar cell, which exhibited, in the reverse scan of the J-V curve, a Voc of 0.814 V, a Jsc of 9.11 mA cm-2, an FF of 55.84%, and an efficiency of 4.14%. These results demonstrate that doping is an effective strategy for tuning the properties of CsPbI3, with particular emphasis on Sb3+ doping, which proved to be the most promising for photovoltaic applications.

COMMITTEE MEMBERS:
Externo ao Programa - 3491716 - ANGELO ANDERSON SILVA DE OLIVEIRA - nullPresidente - 349770 - DULCE MARIA DE ARAUJO MELO
Interno - 1859346 - MIGUEL ANGELO FONSECA DE SOUZA
Externo à Instituição - RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS - UFRN