TY - JOUR
T1 - Fluorochromic properties of undoped and Ln3+-doped CaWO4 phosphor particles
AU - Tsuchiya, Yuto
AU - Hagiwara, Manabu
AU - Fujihara, Shinobu
N1 - Funding Information:
This study was supported by JSPS KAKENHI Grant Number 17K06801.
Publisher Copyright:
© The Author(s) 2018.
PY - 2018
Y1 - 2018
N2 - Undoped and Ln3+-doped (Ln3+ = Eu3+, Tb3+) CaWO4 phosphor particles were synthesized by a hydrothermal method, aiming at generating fluorochromic properties in response to redox reactions. The phosphor particles obtained were first treated with an aqueous L(+)-ascorbic acid solution as a reductant at room temperature, which resulted in a considerable decrease in photoluminescence (PL) intensity of both CaWO4 (the host-lattice blue emission) and CaWO4:Ln3+ (the 4f-4f red or green emission). The quenched PL could then be recovered by treating the particles with a sodium hypochlorite solution as an oxidant also at room temperature. This PL switching behavior was predominantly caused by redox reactions between the solid particles and the redox species in the solutions based on a change of W6+/W5+ valance states of the CaWO4 host crystal. More interestingly, CaWO4:Eu3+ exhibited a change of emission colors, depending on the excitation wavelength, due to different sensitivity of the host emission and the Eu3+ emission to the redox treatment. Such a changeable fluorochromism is regarded as a newly developed function of the phosphor materials for use in facile optical detectors and sensors.
AB - Undoped and Ln3+-doped (Ln3+ = Eu3+, Tb3+) CaWO4 phosphor particles were synthesized by a hydrothermal method, aiming at generating fluorochromic properties in response to redox reactions. The phosphor particles obtained were first treated with an aqueous L(+)-ascorbic acid solution as a reductant at room temperature, which resulted in a considerable decrease in photoluminescence (PL) intensity of both CaWO4 (the host-lattice blue emission) and CaWO4:Ln3+ (the 4f-4f red or green emission). The quenched PL could then be recovered by treating the particles with a sodium hypochlorite solution as an oxidant also at room temperature. This PL switching behavior was predominantly caused by redox reactions between the solid particles and the redox species in the solutions based on a change of W6+/W5+ valance states of the CaWO4 host crystal. More interestingly, CaWO4:Eu3+ exhibited a change of emission colors, depending on the excitation wavelength, due to different sensitivity of the host emission and the Eu3+ emission to the redox treatment. Such a changeable fluorochromism is regarded as a newly developed function of the phosphor materials for use in facile optical detectors and sensors.
UR - http://www.scopus.com/inward/record.url?scp=85073833720&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85073833720&partnerID=8YFLogxK
U2 - 10.1149/2.0171805jss
DO - 10.1149/2.0171805jss
M3 - Article
AN - SCOPUS:85073833720
SN - 2162-8769
VL - 7
SP - R50-R56
JO - ECS Journal of Solid State Science and Technology
JF - ECS Journal of Solid State Science and Technology
IS - 5
ER -