Tunable white luminescence and energy transfer in Cu+, REI3+co-doped sodium silicate glasses
There has been a growing focus on research of white light-emitting-diodes (W-LEDs) in recent years not only because of their significant economical and technological advantages in power efficiency and environmental friendly, but also their potential application in many fields, such as devices indicators, backlights, automobile headlights and general illumination, etc.At present, the common way to generate white light by combing blue LED chip with yellow-emitting phosphors has some drawbacks, such as chromatic aberration and poor white light performance.Thus it is a challenge to develop suitable rare earth ions (REI) doped materials capable of generating white light under ultraviolet (UV) chips excitation.Compared to conventional phosphors used for W-LEDs, REI doped white emitting glasses show excellent optical properties, better mechanical properties, lower production cost, simpler manufacture procedure and epoxy resin free in assembly process.Consequently, the investigations on REI doped white emitting glasses for UV LED chips have been carried out extensively.More recently, noble metal ions and REI co-doped systems, such as Ag/Eu3+,Au/Eu3+ co-doped glasses, had attracted much attention for their potential application in generating white emission via energy transfer (ET) process from noble metal pieces to REI.However, few reports have been carried out on Cu+, REI3+ co-doped materials.Fluorescence of Cu+ and (or) (Cu+)2 pairs comes from d9s→d10 (s→d) transition, which is forbidden strictly for free ion but allowed partially in solids by electronic coupling with lattice vibrations of odd-parity.In general, the excited s state splits into singlet (1T2g, 1Eg) and triplet (3T2g, 3Eg) components, and then the triplets split further by spin-orbit interactions.Thus Cu+ presents broad excitation at UV band and emission at visible (VIS) bands, which are very sensitive to material compositions and can be tuned widely.Accordingly, ET process and white light may be obtained by co-doping Cu+ with REI in proper host matrix.The elaboration and luminescent investigation of Cu+, REI3+ co-coped systems will be very important and interesting.In this paper, sodium silicate glasses are selected as host materials due to their high transparency, good solubility for REI without forming ion clusters and wide range for chemical modifications.The luminescent properties of Cu+,Eu3+ co-doped and Cu+,Sm3+ co-doped glasses, ET from Cu+ to REI3+ were investigated systemically.Tunable emission from green through yellowish white to red was obtained.
Hai Guo RongFei Wei YunLe Wei
Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
国内会议
杭州
英文
14-15
2014-05-15（万方平台首次上网日期，不代表论文的发表时间）