Luminescence of Pulsed-Laser-Deposited SrAl[sub 2]O[sub 4]:Eu,Dy Thin Film and Its Role as a Stress Indicator

Abstract

The ultimate goal of the present investigation was to develop an SrAl2normalO4:Eu ,Dy thin-film phosphor on the surface of mechanical test specimens to act as a stress or crack indicator during testing. As a preliminary step, SrAl2normalO4:Eu ,Dy thin-film phosphors were deposited on several conventional substrates such as quartz glass, Si(111), Si(001), and corrugated quartz glass using a pulsed laser deposition (PLD) technique. Processing parameters were optimized, in an attempt to enhance the efficiency of luminescence of the SrAl2normalO4:Eu ,Dy thin-film phosphor. The optimal PLD processing conditions for the SrAl2normalO4:Eu ,Dy thin-film phosphor were different from that for other conventional oxide thin-film phosphors in that an oxygen supply during the PLD process was not necessary, a postdeposition annealing in an oxidizing atmosphere was ineffective, and the corrugated substrate did not have a significantly enhanced extraction efficiency. By adopting the best PLD processing conditions, based on the preliminary depositions on conventional substrates, the SrAl2normalO4:Eu ,Dy thin-film phosphor was deposited on the surface of a compact tension specimen composed of polycrystalline Al2normalO3 and the applicability of the SrAl2normalO4:Eu ,Dy thin-film phosphor as a stress or crack indicator was verified in an actual mechanical test.

Strong mechanoluminescence induced by elastic deformation of rare-earth-doped strontium aluminate phosphors

“…(19) indicates that the ML emission should start appearing after a threshold pressure P c , and then for small value of P 0 , the value of I m should increase linearly with P 0 , However, Eq. (20) shows that for large value of P 0 , the ML intensity should increase exponentially with P 0 .…”

“…Tanaka et al [19] have reported the ML of alkaline earth aluminate polycrystals doped with Dy 3+ . Sohn et al [20] and Yamada et al [21] have prepared the thin film of SrAl 2 O 4 :Eu,Dy phosphors and shown them to be suitable for stress indicators. Li et al [22] have reported the real-time monitoring of dynamic stress concentration by using the mechanoluminescent sensing film of SrAl 2 O 4 :Eu,Dy.…”

Quasi-dynamic visualization of crack propagation and bridging evolution in Si3N4 and SiC ceramics by mechano-luminescence

“…The ML phenomenon arising in SrAl 2 O 4 :Eu,Dy phosphors began to be utilized as a stress indicator, since the compounds were prepared in bulky epoxy mixture forms. More recently we have introduced some additional pragmatic usages of SrAl 2 O 4 :Eu,Dy phosphors, such as sintered ceramics [19], paints [17], and thin films [20] in an attempt to achieve an efficient stress indicator. These new developments could be very powerful from a practical point of view when used for conventional mechanical testing such as a stress or crack indicator.…”

Preparation and characterization of fiber-textured SrAl2O4:Eu films grown using a homo-buffer layer

“…Recent research, however, indicates that SAOE possesses mechanoluminescent (ML) properties, which have been comprehensively investigated by the Xu group [11][12][13][14]. Among the examined ML materials SAOE is one of the most intense and we believe that SAOE film is a promising candidate for novel application as, for example, mechanooptical devices and triboluminescence skin sensors [15].…”