title: Antenna Effect on the Organic Spacer-Modified Eu-Doped Layered Gadolinium Hydroxide for the Detection of Vanadate Ions over a Wide pH Range.
abstract: The excitation of the adsorbed vanadate group led to the red emission arising from the efficient energy transfer to Eu-doped layered gadolinium hydroxide (LGdH:Eu). This light-harvesting antenna effect allowed LGdH:Eu to detect selectively a vanadate in aqueous solution at different pHs. Because vanadate exists in various forms by extensive oligomerization and protonation reactions in aqueous solution depending on pH, it is important to detect a vanadate regardless of its form over a wide pH range. In particular, spacer molecules with long alkyl chains greatly facilitated access of a vanadate antenna into the interlayer surface of LGdH:Eu. The concomitant increase in adsorption capacity of LGdH:Eu achieved a strong antenna effect of vanadate on the red emission from Eu(3+). When a suspension containing LGdH:Eu nanosheets (1.0 g/L) was used, the vanadate concentration down to 1 × 10(-5) M could even be visually monitored, and the detection limit based on the (5)D0 → (7)F2 emission intensity could reach 4.5 × 10(-8) M.
authors.affiliation: Department of Applied Chemistry, College of Applied Science and Institute of Natural Sciences, Kyung Hee University , Gyeonggi 446-701, Korea.
authors.forename: Heejin
authors.initials: H
authors.lastname: Jeong
authors.affiliation: Department of Applied Chemistry, College of Applied Science and Institute of Natural Sciences, Kyung Hee University , Gyeonggi 446-701, Korea.
authors.forename: Byung-Il
authors.initials: BI
authors.lastname: Lee
authors.affiliation: Department of Applied Chemistry, College of Applied Science and Institute of Natural Sciences, Kyung Hee University , Gyeonggi 446-701, Korea.
authors.forename: Song-Ho
authors.initials: SH
authors.lastname: Byeon
keywords: adsorption; antenna effect; energy transfer; layered gadolinium hydroxide; vanadate