Banca de QUALIFICAÇÃO: CARLOS ALBERTO ALVES DE VASCONCELOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CARLOS ALBERTO ALVES DE VASCONCELOS
DATE: 10/05/2023
TIME: 14:00
LOCAL: Auditório do IF
TITLE:

Investigation the optical and structural properties of Mn-doped Sb2S3 nanocrystals embedded in host glass

KEY WORDS:

Mn2+ dopant; Sb2S3 nanocrystals; optical properties; structural properties; glass

PAGES: 79
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

The search for earth-abundant and non-toxic elements is essential for the manufacture of sustainable optical devices. In this context, dilute magnetic semiconductor (DMS) nanocrystals (NCs) xMn-doped Sb2S3 embedded in host glass were synthesized by the fusion method. Transmission electron microscopy images show the formation of xMn-doped Sb2S3 NCs with increasing size (2.1 to 3.8 nm) as a function of concentration (x = 0.00 to 0.40), respectively. Energy dispersive X-ray spectroscopy analyzes confirm the S, Sb and Mn precursor elements of DMS NCs. Atomic and magnetic force microscopy measurements show the magnetic contrast
patterns resulting from the incorporation of Mn atoms into the structure of Sb2S3. The electronic paramagnetic resonance spectrum confirms the presence of Mn2+ ions (3d5) located in the crystal field of the Sb2S3 semiconductor due to six hyperfine transitions. The redshift of the Raman vibrational mode (1Ag) with increasing xMn concentration gives strong evidence for the presence of Mn2+ ions in sulfur vacancies (VS) in the Sb2S3 unit cell. Optical absorption and photoluminescence (PL) spectroscopy measurements for xMn-doped Sb2S3 NCs show the subtle tunable redshift of the band gap and excitonic recombination in the green-red region, with increasing x concentration. PL confirms that dopant Mn2+ ions fill VS2 that are dominant in Sb2S3. Therefore, the position of the energy states after the increasing concentration of Mn2+ dopant ions gives rise to a luminescence insight for a future scenario of research and applications involving sustainable DMS NCs.

BANKING MEMBERS:
Interno(a) - 1695829 - ANDRE DE LIMA MOURA
Presidente - 1247925 - ANIELLE CHRISTINE ALMEIDA SILVA
Interno(a) - 1638021 - TIAGO HOMERO MARIZ DO NASCIMENTO