Photoluminescence from Electrodeposited Zinc Oxide Films Modified with Eu Ions

Abstract

An account of a simple method of prodvcing short pulses of radiofrequency energy is given, together with notes on its application in the investigation of wireless echoes of short delay. Details of simultaneous visual and photographic methods of delineating such echoes are also described. The discussion of sample records and results serves as a basis for drawing conclusions concerning the relative advantages of the frequency-change and group-retardation methods of investigating the ionized regions of the upper atmosphere.

Photoluminescence of Electrodeposited ZnO Hybrid Thin Films

“…Although precise evaluation of the light extinction by the molecule is difficult, because that by ZnO slightly differ from sample to sample, rather high quantum yields of 9.9 and 21.2% were determined in Case 1 for Photoluminescence ofElectrodeposited ZnO Hybrid Thin Films dcbpy-Eu 3 + complex bound to ZnO excited at 310 and 370 nm, respectively (Table 1). These results suggest more efficient energy transfer from dcbpy than CL I. PL measurements at 20 K and room temperature indicated that this sample retains PL intensity at room temperature being about half of that at 20 K, suggesting that non radiative decay of the excited state is effectively suppressed in the hybrid film [24]. For Case 2, however, these values drop to 1.1 and 0.7%, respectively, suggesting rather inefficient or no energy transfer from ZnO that then only filters UV light to be absorbed by the complex.…”

Photoluminescence from Eu3+ Ions Doped in ZnO Films Sputter-Deposited with H2O Vapor Gas

“…Considerable efforts have been devoted to the Eu 3þ -doped ZnO system in recent years since the 4f intrashell transitions of Eu 3þ ions emit red light with a sharp spectral width. [1][2][3][4][5][6][7][8][9][10][11][12] This characteristic is advantageous for vacuum fluorescent and field emission displays.…”

“…Exploiting photoluminescence (PL) through the indirect excitation of Eu 3þ ions is a feasible approach at the research stage to reach the goal of achieving electroluminescence. 7) Despite excessive expectations, emissions from Eu 3þ through exciting ZnO host crystal have turned out to be rather weak or failed to be observed, 3,4,8,10,11,13,14) while direct excitation of Eu 3þ has yielded emissions with reasonable intensities. Inefficient transfer of excitation energies from the ZnO crystal to Eu 3þ ions has been pointed out, but its microscopic origin remains unclear.…”

Fabrication of Carbon Nanotube/Zinc Oxide Composite Films by Electrodeposition

“…3) Furthermore, it allows us to add novel functionalities to the ZnO films, i.e., the ZnO films can be modified with functional materials, such as dye molecules for dyesensitized solar cells 3,4) and lanthanoid ions for fluorescent films. [5][6][7] In this work, we chose carbon nanotubes (CNTs) as a functional material. Since their discovery in 1991, 8) CNTs have attracted much attention due to their excellent electronic and structural properties.…”