Synthesis-dependent structural and optoelectronic properties of semicrystalline LiNbO3:SiO2 hybrid silicates
Por:
Morales-Saavedra, Omar G., Chavira, Elizabeth
Publicada:
1 ago 2023
Ahead of Print:
1 jul 2023
Resumen:
Polycrystalline ceramics of lithium niobate (LNO) were prepared via
standard hydrothermal and solid-state chemistry reactions, and by the
sol-gel method implementing acrylamide polymerization. Congruent LiNbO3
trigonal perovskite phases crystallized in the R3c (161) space group
[3 m (C3v) polar point group] were attained in all cases. Average
grain and crystallite sizes ranging 127-895 nm and 35-40 nm were
obtained depending on the implemented synthetic route. As prepared LNO
powders were embedded in mesoporous a-SiO2 sonogel networks at different
dopant rates to conform semicrystalline LiNbO3:SiO2 hybrid silicates
with differentiated structural and optoelectronic (OE) properties.
Intensive morphological, structural, spectroscopic, and nonlinear
optical (NLO) characterizations were performed to explore these novel
composites' structural and photophysical properties for lead-free
ferroelectric composites applications. Results show that the implemented
doping rates, the massive porosity of the sonogel matrix and related
defective bonding environment, promote generalized host-guest molecular
interactions influencing the electronic and oxidation states, and the
radiative transitions of the hybrid glasses through surface-assisted
mechanisms and chemical charge-transfers. Moreover, the ferroelectric
nature of LNO allow the observation of SHG activity in the hybrid
sonogel (HSG) phases due to an average macroscopic crystallite alignment
attained along the polycondensation stage of the solid solutions. Bulk
NLO susceptibilities and molecular hyperpolarizabilities in the 9.62 x
10-11 and 10-23 esu range were estimated, respectively. Depending on the
implemented synthetic method and in-gap hybridized levels, energy gap
narrowing was also observed for the LNO/HSG glasses with energy gaps as
low as 3.05 eV.
Filiaciones:
Morales-Saavedra, Omar G.:
Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior S/N, México City, 04510, Mexico
Univ Nacl Autonoma Mex, Inst Ciencias Aplicadas & Tecnol, Circuito Exterior S-N,Ciudad Univ, Mexico City 04510, Mexico
Chavira, Elizabeth:
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior S/N, México City, 04510, Mexico
Univ Nacl Autonoma Mex, Inst Invest Mat, Circuito Exterior S-N,Ciudad Univ, Mexico City 04510, Mexico
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