Yellow/Orange-Emitting ABZn₂Ga₂O₇:Bi³⁺(A = Ca, Sr; B = Ba, Sr) Phosphors: Optical Temperature Sensing and White Light-Emitting Diode Applications

Abstract

Recently, there has been growing interest in developing Bi3+-activated luminescence materials for optoelectronic applications. Herein, new yellow/orange-emitting ABZn2Ga2O7:Bi3+ (ABZGO, A = Ca, Sr; B = Ba, Sr) phosphors with tunable optical properties are synthesized by an alkaline earth cation substitution. When Sr2+ substitutes Ca2+ and Ba2+, the excitation wavelength has a red shift from 325 to 363 nm, matching well with the n-UV chip based white light-emitting diodes (WLEDs). CaBaZn2Ga2O7:0.01Bi3+ (CBZGO:0.01Bi3+) exhibits two evident emission peaks at 570 and 393 nm originating from the respective occupation of Ca and Ba sites by Bi3+ ions. The optical tuning of the CBZGO:Bi3+ phosphor is achieved by changing the Bi3+ doping content and excitation wavelength based on the selected site occupation. Differently, both SrBaZn2Ga2O7:0.01Bi3+ (SBZGO:0.01Bi3+) and Sr2Zn2Ga2O7:0.01Bi3+ (SZGO:0.01Bi3+) phosphors exhibit a single broad emission band, peaking at 600 and 577 nm, respectively. Two different Bi3+ sites are also verified respectively in SBZGO and SZGO hosts by the Gaussian fitting of the asymmetric PL spectra and lifetime analysis. The different luminescence behaviors of ABZGO:0.01Bi3+ phosphors should be ascribed to the synergistic effect of the centroid shift, crystal-field splitting, and Stokes shift. Moreover, the temperature-dependent PL spectra reveal that cation substitutions of Sr2+ for Ca2+ and Ba2+ can efficiently improve the thermal stability of ABZGO:0.01Bi3+ phosphors. In view of different thermal responses to various temperatures for two emission peaks of the CBZGO:0.01Bi3+ phosphor, an optical thermometer is designed and has a good relative sensitivity (S r = 1.453% K–1) at 298 K. Finally, a WLED with CRI = 97.9 and CCT = 3932 K is obtained by combining SZGO:0.01Bi3+ and BAM:Eu2+ phosphors with a 370 nm n-UV chip, demonstrating that SZGO:0.01Bi3+ is an excellent yellow-orange-emitting phosphor for n-UV WLED devices. This work stimulates the exploration of optical tuning by cation substitution to obtain remarkable luminescence materials for optical temperature sensing and WLED applications.

Recent Advances in Bismuth Ion‐Doped Phosphor Materials: Structure Design, Tunable Photoluminescence Properties, and Application in White LEDs

“…[ 21 ] Thus, numerous research works have focused on the Bi 3+ ‐doped phosphors with tunable emission colors across the white light area pumped with UV/n‐UV chips in single‐phase hosts. [ 22 ] It is considered that a single‐component ultra‐broadband phosphor for full‐spectrum light based on crystal field control of multiple Bi 3+ emission centers is an appropriate choice to produce high quality white light. [ 23 ] Furthermore, the warm white light in single‐phase hosts can also be achieved by designing energy transfer from Bi 3+ to other activators (Eu 3+ , Mn 4+ , Sm 3+ , and Mn 2+ ).…”

Visible-light excited polar Dion–Jacobson Rb(Bi1−xEux)2Ti2NbO10perovskites: photoluminescence properties andin vitrobioimaging

“…3a. To explain the thermal quenching behavior, an Arrhenius type activation model is introduced, and the Arrhenius equation [61][62][63] is given by…”

Efficient red and broadband near‐infrared luminescence in Mn2+/Yb3+‐doped phosphate phosphor

“…Currently, the main commercial WLEDs are to combine a 460 nm emitting LED chip and a yellow‐emitting YAG:Ce 3+ phosphor 12‐16 . However, this combination suffers from the disadvantages of high correlated color temperature (CCT) and low color rendering index (Ra) because of insufficient red light components 17‐20 . Another alternative means for obtaining white light is by combining near ultraviolet LED (n‐UV‐LED) chips with tricolor phosphors 21‐24 .…”

“…[12][13][14][15][16] However, this combination suffers from the disadvantages of high correlated color temperature (CCT) and low color rendering index (Ra) because of insufficient red light components. [17][18][19][20] Another alternative means for obtaining white light is by combining near ultraviolet LED (n-UV-LED) chips with tricolor phosphors. [21][22][23][24] Either way, the red light component is essential for obtaining high-quality white light.…”