Preparation and characterization of thin films of Nb2O5 doped with Li+ for possible architecture applications.

Author(s)

Luciana de Oliveira Melo

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 2001-09-12

Examining board members

Agnieszka Joanna Pawlicka Maule; Annette Gorenstein; Maximo Siu Li

• Advisor: Agnieszka Joanna Pawlicka Maule

Abstract

Present work shows the preparation and characterization of niobium (V) oxide films (Nb2O5) doped with lithium trifluoromethanesulfonate (CF3SO3Li). The main objective of lithium salt addition was to verify its influence on the opto-electrochemical performance of the niobia films. Sols to deposition of the films were prepared by sol-gel process. The mixture of NbCl5 butanol, acetic acid and lithium salt was submitted to ultrasonic irradiation for some minutes. After, films were deposited by dip-coating on glass substrate re-covered with conductor layer (ITO-Asahi). Films were submitted to the thermal treatment between 400 and 600&#176C during some minutes in air atmosphere. The electrochemical reversibility of these films was studied by cyclic voltammetry and chronoamperometry. Their optical transmission measurements were performed in-situ in the UV-VIS range (between 350 and 800nm). Microscopic analysis (SEM, EDX, AFM) was made to check the texture, composition and topography of the films. Infrared spectroscopy measurements were made to sols characterizations and thermal analyses (TGA/ DTA) and X-ray diffraction to the precipitates. The possible use these films in architecture was studied by comparing with the optic transmission results of the common glass. (AU)