In several host materials, the Eu ions are in trivalent states
because of their chemical stability. It is thus necessary to
reduce Eu3+ to Eu2+ ions in phosphors to develop the Eu2+
doped optical materials. The most widely used reduction
method is to heat the samples under a high reducing atmosphere,
such as H2, H2/N2, or CO, etc. However, there have
been reports that in some host materials, Eu3+ ions can be
reduced to Eu2+ ions by a solid state reaction at high temperature
in air[7]. It is the so-called ‘abnormal’ reduction of
RE3+→RE2+ (RE=Sm, Eu, Tm, Yb)[8-10], and it is proposed
that nonequivalence substitution of rare earth ions into matrix
and the rigid three-dimensional network such as BO4
tetrahedral is necessary for reduction of trivalent rare earth
ions in air[11-13].
In several host materials, the Eu ions are in trivalent statesbecause of their chemical stability. It is thus necessary toreduce Eu3+ to Eu2+ ions in phosphors to develop the Eu2+doped optical materials. The most widely used reductionmethod is to heat the samples under a high reducing atmosphere,such as H2, H2/N2, or CO, etc. However, there havebeen reports that in some host materials, Eu3+ ions can bereduced to Eu2+ ions by a solid state reaction at high temperaturein air[7]. It is the so-called ‘abnormal’ reduction ofRE3+→RE2+ (RE=Sm, Eu, Tm, Yb)[8-10], and it is proposedthat nonequivalence substitution of rare earth ions into matrixand the rigid three-dimensional network such as BO4tetrahedral is necessary for reduction of trivalent rare earthions in air[11-13].
การแปล กรุณารอสักครู่..
In several host materials, the Eu ions are in trivalent states
because of their chemical stability. It is thus necessary to
reduce Eu3+ to Eu2+ ions in phosphors to develop the Eu2+
doped optical materials. The most widely used reduction
method is to heat the samples under a high reducing atmosphere,
such as H2, H2/N2, or CO, etc. However, there have
been reports that in some host materials, Eu3+ ions can be
reduced to Eu2+ ions by a solid state reaction at high temperature
in air[7]. It is the so-called ‘abnormal’ reduction of
RE3+→RE2+ (RE=Sm, Eu, Tm, Yb)[8-10], and it is proposed
that nonequivalence substitution of rare earth ions into matrix
and the rigid three-dimensional network such as BO4
tetrahedral is necessary for reduction of trivalent rare earth
ions in air[11-13].
การแปล กรุณารอสักครู่..