resulted in the formation of Ba2NiTi5O13 particles with various
morphology (i.e. sphere, cube, rod), which were deduced to be
caused by citric acid that tends to absorbed on certain dimension
of the Ba2NiTi5O13 particles as the CA was added. Abreu Jr. et al.
[18] showed that in the sol–gel method, which is commonly
known as the Pechini method, are practiced by using citrate salts
or mixtures of common salts with CA as precursor. They further
showed that the citrate will form complexations via its carboxylate
groups with empty orbitals of metals [18]. As a matter of fact from
Refs. [17,18] it can be seen that CA plays significant roles in the
particle morphology. Asakura et al. [19] reported the decrease in
particle diameter from 10.2 to 4.0 nm with an increase in CA. They
further [19] showed that the internal quantum efficiency of the
photoluminescence (PL) due to the 4f–5d transition of Ce3 þ
increases from 22.0% to 40.1% with increasing amount of CA.
Motivated by Refs. [17–19] and since there has not been a
report on the effects of CA in the ZnAl2O4 doped and co-doped
phosphors, in this study, we mainly focus on the effect of Zn/CA
mole fraction 0.083–1.3 during sol–gel synthesis of the undoped
and 1.5% Pb2 þ doped ZnAl2O4 phosphors. Specifically, we report
these effects based on the structure, morphology and photo-
luminescence properties. In addition, there are scarce reports on
the sol–gel synthesis of ZnAl2O4:Pb2 þ in literature to date. The
main aim is to produce phosphor material that can be used for
blue light emitting devices.