应物理科学与技术学院王育华教授邀请，原三星日本（SRJ）研发技术部部长，现日本电气化学公司（DENKA）技术顾问濑户俊孝博士于2015年10月19至21日来校作学术报告, 欢迎大家积极参加！

报告一

题目：Recently found phosphors for blue-LED and their industrial significance

时间：2015年10月20日 (星期二) 上午9:30-11:30

地点：格致楼5004室

报告内容：

There are various combination of LED and phosphor in white LED lighting. The combination of blue LED, yellow phosphor, and red phosphor is mainstream, still now. The quantum efficiency of each phosphor and the fitness between each isochromatic curve and emission peak of each phosphor are important on the point of increasing emission efficiency of white LED lighting, while the correlation between the luminosity curve and the white emission curve has hidden importance. Its concrete examples will be described.

The key points for going up to the stage of practical use are 1. emission efficiency of white lighting, and 2. duration of life of phosphor under irradiation. Yellow and red phosphors of more than 10 for LED have been found, while only a part of them is successfully used in practical white LED lighting. Its reason will be explained. Superior and inferior points of SrLiAl3N4:Eu and others found in recent years will be explained.

报告二

题目： Structural detail of Eu2+ or Ce3+- activated phosphors for LED

时间：2015年10月20日(星期二)下午15:00-17:00

地点:格致楼5004室

报告内容：

Excitation and emission spectrum of phosphors activated by Eu2+ or Ce3+ for LED are much influenced by crystal field splitting and nephelauxetic effect of 5d orbital concerning 4f→5d transition of Eu2+ or Ce3+. Crystal field splitting of 5d orbital of phosphors activated by Eu2+ or Ce3+ is almost equivalent to that of 3d orbital of transition metal cation. Therefore, it is possible to roughly understand and visualize the correlation between the wavelength of excitation - emission peaks and the structure of nitrogen or oxygen around Eu2+ or Ce3+ by use of the relation between the coordination structure and the ligand field splitting previously studied in the field of 3d transition metal. It is useful for searching new LED phosphors. It will be described.

It will be explained how much the wavelength of excitation – emission peaks has the correlation with the N(O) coordination number or N/(N+O) ratio on many nitride, oxynitride, and oxide phosphors activated by Eu2+, etc. for LED found so far.