Nanocrystalline sodium niobate (NaNbO3) powders doped with Er3+ and Er3+/Yb3+ ions have been successfully synthesized via Pechini sol–gel method for the first time. The prepared NaNbO3 nanocrystalline compounds are single phase, with orthorhombic structure, and have an average particle size of 60 nm. The Raman investigation reveals a disorder nature of the host. Upon near infrared excitation with an 970 nm radiation, an intense green and a weaker red upconversion emission was observed from the 2H11/2, 4S3/2 4I15/2 and 4F9/2 4I15/2 transitions respectively, along with 1.55 !m emission from 4F13/2 !4I15/2 transition for both Er3+ doped and Er3+/Yb3+ codoped NaNbO3. A two photon process is found to be the origin of the upconverted emission. An enhancement of nearly 30 times of the upconverted emission is observed in the Er3+/Yb3+ codoped than the Er3+ doped NaNbO3, suggesting a possible use of the present materials in field where the upconversion properties can be useful, such as in solar cells or biomedical applications.
Synthesis, Structural Properties and Upconversion Emission of Er3+ and Er3+/Yb3+ Doped Nanocrystalline NaNbO3
PICCINELLI, FABIO;SPEGHINI, Adolfo;GIAROLA, Marco;MARIOTTO, Gino;
2012-01-01
Abstract
Nanocrystalline sodium niobate (NaNbO3) powders doped with Er3+ and Er3+/Yb3+ ions have been successfully synthesized via Pechini sol–gel method for the first time. The prepared NaNbO3 nanocrystalline compounds are single phase, with orthorhombic structure, and have an average particle size of 60 nm. The Raman investigation reveals a disorder nature of the host. Upon near infrared excitation with an 970 nm radiation, an intense green and a weaker red upconversion emission was observed from the 2H11/2, 4S3/2 4I15/2 and 4F9/2 4I15/2 transitions respectively, along with 1.55 !m emission from 4F13/2 !4I15/2 transition for both Er3+ doped and Er3+/Yb3+ codoped NaNbO3. A two photon process is found to be the origin of the upconverted emission. An enhancement of nearly 30 times of the upconverted emission is observed in the Er3+/Yb3+ codoped than the Er3+ doped NaNbO3, suggesting a possible use of the present materials in field where the upconversion properties can be useful, such as in solar cells or biomedical applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.