Realizing Visible Light Excitation of Tb~(3+) via Highly Efficient Energy Transfer from Ce~(3+) for LED-Based Applications

摘要

Trivalent terbium (Tb3+)-activated luminescence materials usually show highly efficient green emission with the full width at half maximum of merely 10 nm, but suffer from the unsatisfactory excitable wavelength (380 nm) as well as the inefficient light absorption. Here, the realization of efficient visible light excitation of Tb3+ is demonstrated in terbium-concentrated garnet Ca2TbHf2Al3O12 (CTHA) by introducing Ce3+ as the sensitizer. Owing to highly efficient energy transfer from Ce3+ to Tb3+, CTHA:Ce3+ combines advantages of the extra narrow green emission of Tb3+ peaking at 544 nm and the efficient broad excitation of Ce3+ covering the short-wavelength visible light from 380 to 450 nm. The color gamut of the prototype white light-emitting diode (LED) by using CTHA:Ce3+ as the green emitter can reach 95% (coverage ratio) of National Television Standards Committee (NTSC) space in Commission Internationale de L'Eclairage (CIE) 1931, indicating its great potential for LED (or laser diode)-based applications.