TAILIEUCHUNG - A study of red emitting phosphor ofK2SiF6:Mn4+ for warm white leds
This study focuses on the fabrication of red-emitting phosphor based on K2SiF6: Mn4+ phosphor. Characteristic emissive peaks in the red region of the Mn4+ ions involve the energy transfer from spin-forbidden states of 2Eg → 4A2, showing narrow band emission peaks at 609, 614, 631, 635 and 647 nm. | Vietnam Journal of Science and Technology 56 (1A) (2018) 183-188 A STUDY OF RED-EMITTING PHOSPHOR OF K2SiF6:Mn4+ FOR WARM WHITE LEDs Nguyen Le Anh1, Tran Tat Dat2, Nguyen Minh Vuong1, Nguyen Duy Hung2, Thanh-Tung Duong2, * 1 Department of Physics, Quy Nhon University, 170 An Duong Vuong, Quy Nhon, Binh Dinh 2 Nano Opto-Electronic Lab., Advanced Institute for Science and Technology, Hanoi Univesity of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Ha Noi * Email: Received: 15 August 2017; Accepted for publication: 26 February 2018 ABSTRACT This study focuses on the fabrication of red-emitting phosphor based on K2SiF6: Mn4+ phosphor. Characteristic emissive peaks in the red region of the Mn4+ ions involve the energy transfer from spin-forbidden states of 2Eg → 4A2, showing narrow band emission peaks at 609, 614, 631, 635 and 647 nm. Meanwhile, their absorptive peaks involve the energy transfer from spin-allowed states of 4A2 → 4Tg; the excited wavelength of the Mn4+ is in the range 360 - 460 nm. Thus, the K2SiF6: Mn4+ phosphor is particularly suitable for redundancy of 460 nm - Light Emitting Diode (LED); it complements the red emission of the commercial White LEDs. Keywords: photo-conversion phosphor, red emission, WLED. 1. INTRODUCTION The first light emitting diodes (LEDs) were developed in the early 1960s. However, they used less energy and only produced light at lower frequencies, corresponding to the red light of the spectrum. The first high intensity blue LED was created by Shuji Nakamura, Nichia Corporation in 1994. The existence of high performance blue - LED lead to the development of "phosphor converted White LEDs" (pc-WLEDs). In which, use a coating film of phosphor powder to convert some of the blue light that emits into the red and green light that produce the white light [1]. Isamu Akasaki, Hiroshi Amano and Shuji Nakamura were later awarded the 2014 Physics Nobel Prize for the invention of blue LED. .
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