Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 11, pp. 1903−1910.
Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.V. Bakhmet’ev, M.M. Sychev, V.G. Korsakov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 11, pp. 1770−1777.
INORGANIC SYNTHESIS AND INDUSTRIAL
A Model of Active Acid-Base Surface Sites for Zinc Sulﬁ de
V. V. Bakhmet’ev, M. M. Sychev, and V. G. Korsakov
St. Petersburg State Institute of Technology (Technical University), St. Petersburg, Russia
Received March 17, 2010
Abstract—Results of studies into surface properties of ZnS : Cu,Al and ZnS : Cu electroluminescent phosphors
by the indicator method were summarized. The surface and electrooptical properties of these phosphors were
examined in relation to the reaction batch composition and synthesis atmosphere, as well as to heat-treatment and
electron-beam-induced modiﬁ cation regimes. On this basis, the structure of the surface active sites having different
acid powers was established, and a surface model for zinc sulﬁ de electroluminescent phosphors was proposed.
Surface properties of powdered zinc sulﬁ de
electroluminescent phosphors (ELPs) hold much
signiﬁ cance in encapsulation, as well as in interaction
of the powder with the binder during preparation of
light sources. Also, surface defects in ELPs affect the
quantum yield of electroluminescence.
The surface properties of powdered ELPs have been
the subject of much investigations [1, 2]. There exist
published data on the distribution of active sites on the
zinc sulﬁ de ELP particle surface over the acid-base
. However, neither of these studies revealed
the nature of all the active sites, characterized by each
value, that may occur on the surface of
zinc sulﬁ de ELPs.
Elucidation of the surface structure of zinc sulﬁ de
ELPs is of central importance for both improvement
of the characteristics of ELPs and preparation of light
Previous studies in this area were dedicated to
alternating current ZnS : Cu and ZnS : Cu,Al powdered
ELPs [3–11]. Here, we summarized the results of
these and other studies into surface properties of zinc
sulﬁ de ELPs and, on this basis, established the nature of
each of the active sites occurring on the ZnS : Cu and
ZnS : Cu,Al electroluminescent phosphor surface and
proposed a plausible surface model for these ELPs.
Our study was concerned with ZnS : Cu and
ZnS : Cu,Al electroluminescent phosphors. They
were synthesized by calcination of the reaction batch
comprised of zinc sulﬁ de, copper- and aluminum-
containing substances, and fusible agents (sulfur and
ammonium bromide) in quartz crucibles under an active
carbon layer which promoted generation of reductive
atmosphere [4, 6, 9].
After roll blending, weighed portions of the reaction
batch components were calcined in a mufﬂ e furnace
at 800–1000°C, which enabled incorporation of the
activator and co-activator (copper and aluminum) into
the crystal lattice of zinc sulﬁ de.
Calcination of the reaction batch was followed
by low-temperature annealing of the resulting
luminopohores in the mufﬂ e furnace at 650°C, which
promoted decomposition of the supersaturated solid
solution of Cu in ZnS, prepared in the synthesis stage,
and generation of ZnS–Cu
S heterojunctions (x = 1.8–