การเคลือบกระจกหน้าต่างด้วยสารเรืองแสงซิงก์ซัลไฟด์ที่ถูกกระตุ้นด้วยคอปเปอร์คลอไรด์โดยการพิมพ์ซิลค์สกรีน

Abstract

In this work, a window glass form Thaitechnoglass Co., Ltd. was developed to high emission brightness and long degradation of phosphorescent behaviour as called ZWG in dark area by silk screen coating using CuCl2-activated ZnS phosphor (ZnS:Cu). The effects of particle size of ZnS:Cu phosphor, curing temperature and soaking time, degree of reduction atmosphere controlled with CO concentration using charcoal, and film thickness on color, brightness and degradation of phosphorescence were studied. According to ZnS:Cu phosphor slurry preparation and silk screening, the slurry was prepared in the ratio of ethanol : frit : Zn:Cu powder : supperplasticizer at 1 ml : 0.125 g : 2 g : 0.2 ml, respectively. The viscosity of slurry was controlled at 219 cP and the size screening was also controlled at 77 µm. The ZWG was cured at 800oC in a reduction atmosphere. It was found that the ZnS:Cu is the wurtzite phase representing the hexagonal structure and yellowish green emission color at 400-550 nm. The brightness and degradation time increased with decreasing particle size of ZnS:Cu from 94 to 37 nm and with increasing film thickness from 100 to 800 nm due to the sintering and homogeneity of structures. From the results of curing condition, the brightness and degradation time increased with increasing curing temperature from 700 to 800oC and with decreasing soaking time from 60 to 15 min due to the thermal stability and the reduction of ZnO concentration. As the results of degree of reduction atmosphere, the brightness and degradation time increased with increasing CO concentration from 0.029-58.28 g-mol/m3 due to stability of hexagonal structure and the reduction of ZnO concentration. It was concluded that the ZnS:Cu phosphor slurry was prepared using ZnS:Cu powder at 37 nm, film thickness at 800 nm, curing temperature at 800oC for 15 min in the reduction atmosphere at 58.28 g-mol/m3 of CO. These conditions directly affected on the yellowish green emission brightness and degradation time reaching to 89.57 and 24 min 33 sec, respectively.