The purpose of the present study is to develop an understanding of the photoluminescence properties of Mn 2+ -doped zinc silicate (Zn 2 SiO 4 :Mn) phosphors, which have served as a gree-emitting phosphor in many industrial applications. Thus, several experimental techniques, such as time-resolved emission spectra, decay curves, and timeresolved photoluminescence excitation spectra, have been conducted on Zn 2 SiO 4 :Mn phosphors. The characterization has been performed in terms of dopant concentration. The decay curves, together with the characteristic decay time, in particular, are measured as a function of excitation-light wavelength, in the range of 200-520 nm. The decay behavior is strongly dependent on the excitation-light wavelength. The excitation range is categorized into three regimes: the manganese direct excitation range, below the absorption-edge (E T ) energy level; the manganese ionization range, from E T to the optical band-gap energy (E g ) of Zn 2 SiO 4 ; and the intergap transition range, above the E g energy level.

Combinatorial chemistry has been widely applied to the synthesis of a variety of materials such as drugs, various inorganic functional materials, etc. 1-3 In regard to the inorganic materials, most of investigations, which dealt with the combinatorial chemistry, are focused on the solid-state combinatorial chemistry based on thin film technology. [2][3][4][5][6] The present investigation aims at applying the liquid state combinatorial chemistry method to the synthesis of phosphor powders. Unlike the solid-state combinatorial chemistry method based on thin film technology, the method used by the authors adopted a solution method so that it could rather be similar to the combinatorial chemistry used in the pharmaceutical industry. It is, however, noted that the present combinatorial chemistry method is much simpler than the conventional one in that the number of compounds in a batch is far less than the conventional method developed by others. [1][2][3][4][5][6] In this respect, the method adopted in the present investigation is called pseudocombinatorial chemistry method (PCCM). Notwithstanding the above-described shortcoming, PCCM has a great potential when applied to the fine screening of well-known phosphor compounds.PCCM has several merits when applied to the phosphor synthesis, the most significant one of which is the capability of combining the synthesis and the characterization in a very efficient way. The conventional solid-state combinatorial chemistry, in which phosphors are dealt with based on thin film technology, 3-6 is carried out on a very large scale, that is, a huge number of compounds are given on the small substrate and synthesized at the same time, but the amount of each compound is too small to be characterized properly. In the case of the phosphor, the host composition which has been already developed, requires only the fine-tuning of the composition. It is, however, actually very hard to discern the optimum composition among a large number of phosphors showing a similar level of emission intensity. PCCM adopted in the present investigation makes it possible to characterize all the properties of an individual compound in the same way that is adopted for the conventional powder sample. Thus the measurement of conventional spectroscopy, decay, X-ray diffraction (XRD), and scanning electron microscopy (SEM) possible.The main purpose of the present investigation is to find out the composition of BaAl 12 O 19 :Mn phosphor that exhibits the highest luminous efficiency adaptable for plasma display panel (PDP). In fact, only the Zn 2 SiO 4 :Mn phosphor has served as a green component in PDP but recently the BaAl 12 O 19 :Mn phosphor have began to be considered as an alternative. Even though the fact that the BaAl 12 O 19 :Mn phosphor does not fluoresce under UV (254 nm) excitation causes some difficulties in the process of phosphor painting, 7 the emission efficiency of this phosphor under VUV excitation is almost tantamount to that of conventional Zn 2 SiO 4 :Mn phosphor. It should be, however, note...

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