a Laboratorio di Chimica dello Stato Solido, DB, Università di Verona and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I-37134 Verona, Italy
b Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Venezia and INSTM, UdR Venezia, Via Torino 155/b, 30172, Venezia - Mestre, Italy
c Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, Av. Astrofísico Francisco Sanchez, s/n, 38206, La Laguna, Spain
Received 24 January 2012. Accepted 21 April 2012. Available online 26 April 2012.
The synthesis of Ho3 +–Yb3 + codoped titanate nanotubes was carried out successfully via a hydrothermal treatment method from a precursor powder. These novel nanotubes treated at RT, 100 °C and 280 °C were studied with the aim of determining their structural and optical properties. As the thermal treatment was increased, their upconversion emission becomes stronger. This behavior was related to reduction of hydroxyl groups and the water on the surface, which resulted in changes in the interlayer distances of the nanotubes.
