Realizing Visible Light Excitation of Tb3+ via Highly Efficient Energy Transfer from Ce3+ for LED-Based Applications

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.