DaeGwi Kim's research while affiliated with Osaka City University and other places

... Compared with the commonly used nonmetallic modification methods, changing the electronic structure of CDs to provide more active sites is easier, for they have more electrons and vacant orbitals. By introducing transition metal modification, the electronic structure and optical properties of CDs can be adjusted, which greatly expands the application of CDs in catalysis, electricity conduction and so on [22][23][24]. Although transition metals with modified CDs show fluorescent stability, such properties of CDs can be adjusted, which greatly expands the application of CDs in catalysis, electricity conduction and so on [22][23][24]. ...

... These studies have been mostly conducted on NCs with long-chain alkyl ligands, which dissolve well in nonpolar solvents. By contrast, a donor-acceptor pair emission mechanism was recently proposed for water-soluble CIS NCs with cysteine ligands [17]. ...

... Our group has demonstrated that the synergistic combination of polyelectrolytes and carbon nanofillers via layer-by-layer (LbL) assembly creates highly ordered nanocomposites with large PF [3,33]. The LbL method has been utilized for developing multifunctional thin films including bio-film inhabitation, flame retardant, gas sensors, and solar cells [18,34]. LbL coatings are mainly based on electrostatic interactions through charge compensation between oppositely charged components, but other interactions including hydrophobic, van der Waals interactions, π-π interactions, and hydrogen bonding are also employed to form ultra-thin films on various types of substrates [35][36][37][38][39]. ...

... Therefore, it has been used in many photonic applications such as sensors, lasers, luminescent devices, light-emitting diodes, solar cells, and photoconductors. [24][25][26][27][28][29][30][31][32][33] A few research works have been carried out to explore the properties of CdS for enhancing the fluorescence properties of rare-earth-doped sol-gel glass. [34][35][36] One of the recent studies in this direction is the effect of CdS on the emission of Eu 3+ ions implanted in a silicophosphate glass fabricated by the sol-gel method, and it was found that CdS can enhance the photoluminescence (PL) of Eu 3+ ions. ...

... ZnSe thin films have been synthesized using a variety of techniques, including molecular beam evaporation [5], RF magnetron sputtering [12], pulsed laser deposition [4], hydrothermal [13] and chemical bath deposition (CBD) [14][15][16]. The chemical bath deposition appears to be the most suitable method for the growth of ZnSe-based thin films due to its considerable advantages, including simplicity, low cost, low processing temperature [17], easy coating of large areas and high quality of the obtained nanostructured thin films [18]. ...

... 100,103,104 Considering J e−h ≈ 0.3 eV as reported for Jdira, et al . 103 , and taking into account that the maximum of the PL peak in Fig. 10(b) can be used as a measure of E opt , 105 it is possible to obtain that η = 0.8. This value is very close to the theoretical value of η = 0.7 calculated by Jdira, et al . ...

... The decay curve on quartz is fitted according to equation (4) with a median time of 7 ns and a σ = 1.3. The faster decay of the larger QDs was discussed in [44] and explained by the different magnitude of the energy splitting between the bright and dark exciton states. The decay is slightly faster on ZnSe and ZnMnSe. ...

... ZnS has always been a promising material for blue and UV light emitting diodes and laser diodes [1][2][3][4]. When ZnS combines with other materials such as ZnSe, it produces a stimulating and potentially effective heterostructures such as ZnS/ZnSe systems [5][6][7][8]. Such systems are used as phototransistors in the UV detection [4]. ...

... 18,20,29,30) The synthesized NPs reveal hydrophobic properties so that organic solvents are used to disperse these semiconductor NPs. 31) We previously synthesized NPs of compound semiconductors such as CdTe, 32) ZnSe, 33,34) and Mn-doped ZnSe (ZnSe:Mn) 35) NPs using the hydrothermal method, and investigated their optical properties. We adopted ZnSe:Mn/ ZnS core/shell configuration 36) for suppressing the nonradiative recombination at the exposed surfaces of ZnSe:Mn NPs and achieving a higher photoluminescence quantume yield (PLQY). 37) Furthermore we prepared ZnSe/ZnS:Mn/ZnS shell-doped (core/shell/shell) NPs in which the shell was doped with Mn instead of directly doping the ZnSe cores. ...

... These colors demonstrate that the IO QDs have weak fluorescence features. The FL features of IO QDs are completely influenced by the synthetic conditions [38,39]. Several synthesis parameters, such as Fe 3 O 4 NPs concentration, the amount of the citric acid, hydrothermal reaction time, hydrothermal temperature, and total volume of precursors were examined to obtain the IO QDs with optimal quality. ...