title: Morphological and Optoelectronic Characteristics of Double and Triple Lanthanide Ion-Doped DNA Thin Films.
abstract: Double and triple lanthanide ion (Ln(3+))-doped synthetic double crossover (DX) DNA lattices and natural salmon DNA (SDNA) thin films are fabricated by the substrate assisted growth and drop-casting methods on given substrates. We employed three combinations of double Ln(3+)-dopant pairs (Tb(3+)-Tm(3+), Tb(3+)-Eu(3+), and Tm(3+)-Eu(3+)) and a triple Ln(3+)-dopant pair (Tb(3+)-Tm(3+)-Eu(3+)) with different types of Ln(3+), (i.e., Tb(3+) chosen for green emission, Tm(3+) for blue, and Eu(3+) for red), as well as various concentrations of Ln(3+) for enhancement of specific functionalities. We estimate the optimum concentration of Ln(3+) ([Ln(3+)]O) wherein the phase transition of Ln(3+)-doped DX DNA lattices occurs from crystalline to amorphous. The phase change of DX DNA lattices at [Ln(3+)]O and a phase diagram controlled by combinations of [Ln(3+)] were verified by atomic force microscope measurement. We also developed a theoretical method to obtain a phase diagram by identifying a simple relationship between [Ln(3+)] and [Ln(3+)]O that in practice was found to be in agreement with experimental results. Finally, we address significance of physical characteristics-current for evaluating [Ln(3+)]O, absorption for understanding the modes of Ln(3+) binding, and photoluminescence for studying energy transfer mechanisms-of double and triple Ln(3+)-doped SDNA thin films. Current and photoluminescence in the visible region increased as the varying [Ln(3+)] increased up to a certain [Ln(3+)]O, then decreased with further increases in [Ln(3+)]. In contrast, the absorbance peak intensity at 260 nm showed the opposite trend, as compared with current and photoluminescence behaviors as a function of varying [Ln(3+)]. A DNA thin film with varying combinations of [Ln(3+)] might provide immense potential for the development of efficient devices or sensors with increasingly complex functionality.
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Mallikarjuna Reddy
authors.initials: MR
authors.lastname: Kesama
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Sreekantha Reddy
authors.initials: SR
authors.lastname: Dugasani
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Yoo
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Prathamesh
authors.initials: P
authors.lastname: Chopade
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Bramaramba
authors.initials: B
authors.lastname: Gnapareddy
authors.affiliation: Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Korea.
authors.forename: Sung Ha
authors.initials: SH
authors.lastname: Park
mesh_terms: D004247:DNA / Q000737:chemistry*; D055590:Electromagnetic Phenomena; D004735:Energy Transfer; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D044367:Phase Transition
chemical_list: D028581:Lanthanoid Series Elements; D004247:DNA
keywords: Co-doping; DNA lattice; DNA thin film; lanthanide ion; photoluminescence