A Method for the Clean Syntheses of Sulfides/Selenides: II. Ternary Sulfides/Selenides

Article abstract of DOI:10.1149/1.1373659

The syntheses of MGa₂S₄ (where M = Ca, Sr, and Zn), CuMS₂ (where M = In or Cr), Ba₂ZnS₃, and CuInSe₂ by utilizing sulfur or selenium solutions in hydrazine monohydrate are reported. Scanning electron microscope studies of the morphology of the resulting materials prepared by this route are presented. The photoluminescence spectra of the phosphors SrGa₂S₄:Eu, SrGa₂S₄:Ce, ZnGa₂S₄:Mn, CaGa₂S₄:Eu, and Ba₂ZnS₃:Mn are displayed. The method is more environmentally friendly than traditional preparations (very little sulfur-based gases are formed). Additionally, it is a simple and rapid preparation, producing a good yield. The procedure facilitates the formation of ternary metal sulfides or selenides. It is further shown that for optimum performance of SrGa₂S₄:Eu, the phosphor needs to be fired in a reducing atmosphere to convert all of the Eu^3- to Eu²⁺.

Full text of DOI:10.1149/1.1373659

Journal of The Electrochemical Society, 148 ͑7͒ D89-D93 ͑2001͒
D89
0
013-4651/2001/148͑7͒/D89/5/$7.00 © The Electrochemical Society, Inc.
A Method for the Clean Syntheses of SulfidesÕSelenides
II. Ternary SulfidesÕSelenides
,
z
Paul J. Marsh, Dominic A. Davies,* Jack Silver,* David W. Smith, R. Withnall,
and A. Vecht*
Centre for Phosphors and Display Materials, University of Greenwich, Woolwich, London SE18 6PF, United
Kingdom
The syntheses of MGa S ͑where M ϭ Ca, Sr, and Zn͒, CuMS ͑where M ϭ In or Cr͒, Ba ZnS , and CuInSe by utilizing sulfur
2
4
2
2
3
2
or selenium solutions in hydrazine monohydrate are reported. Scanning electron microscope studies of the morphology of the
resulting materials prepared by this route are presented. The photoluminescence spectra of the phosphors SrGa S :Eu.
2
4
SrGa S :Ce, ZnGa S :Mn, CaGa S :Eu, and Ba ZnS :Mn are displayed. The method is more environmentally friendly than
2
4
2
4
2
4
2
3
traditional preparations ͑very little sulfur-based gases are formed͒. Additionally, it is a simple and rapid preparation, producing a
good yield. The procedure facilitates the formation of ternary metal sulfides or selenides. It is further shown that for optimum
3ϩ
2ϩ
performance of SrGa S :Eu, the phosphor needs to be fired in a reducing atmosphere to convert all of the Eu to Eu
.
2
4
©
2001 The Electrochemical Society. ͓DOI: 10.1149/1.1373659͔ All rights reserved.
Manuscript submitted January 31, 2000; revised manuscript received January 25, 2001. Available electronically May 31, 2001.
2
ϩ
We have reported previously the preparation of main group
metal and transition element binary sulfides and selenides using so-
lutions of sulfur or selenium in hydrazine monohydrate, and have
identified the major species present in a hydrazine monohydrate/
phosphors using this method are reported: „1… SrGa S :Eu ͑green
2
4
3
ϩ
ϩ
emission͒, „2… SrGa S :Ce ,Na
͑blue emission͒, „3…
2
4
2ϩ
2ϩ
CaGa S :Eu ͑yellow emission͒, „4… ZnGa S :Mn ͑red emis-
2
4
2 4
2ϩ
sion͒, and „5… Ba ZnS :Mn ͑red emission͒. The adaptable nature
2
3
2Ϫ
1-3
sulfur solution as the tetrasulfide ion (S4 ). The precipitate from
these reactions has been identified as a mixture of metal sulfide and
excess sulfur ͑in this method all the excess sulfur is precipitated
of this method is further illustrated by the synthesis of the nonlumi-
nescent ternary sulfides: „6… copper chromium disulfide, „7… copper
indium disulfide, which has previously been synthesized as a poten-
1
17-21
from solution͒. Full details of the mechanism of this reaction have
tial material for use in thin film solar cells,
and „8… copper
1
been reported elsewhere. This method of preparing binary metal
indium diselenide, which is one of the most promising p-type semi-
conductor materials being investigated for thin film solar cells.2
2-27
sulfides and selenides has a number of advantages, these include ͑i͒
a protocol for the precipitation of a wide range of p and d block
metal sulfides, ͑ii͒ the reaction is rapid to use and requires only
minimum safety regulations ͑sources of ignition and oxidants must
be avoided͒, ͑iii͒ a low sulfurous gas emission during high tempera-
ture processing, and ͑iv͒ a low potential for other metal contamina-
tion because of the nature of the chemicals used.
Experimental
Materials.—Ammonium chloride ͑99.5%͒, barium acetate
99%͒, calcium chloride hexahydrate ͑98%͒, chromium chloride
͑
hexahydrate ͑AnalaR͒, copper chloride dihydrate ͑AnalaR͒, copper
acetate monohydrate ͑AnalaR͒, hydrazine monohydrate ͑99%͒, hy-
drochloric acid ͑AnalaR͒, manganous acetate ͑99%͒, isopropanol,
and zinc acetate dihydrate ͑98ϩ%͒ were obtained from BDH
Chemicals Ltd. Ammonium carbonate ͑ACS reagent͒, cerium chlo-
ride heptahydrate ͑99.99%͒, europium acetate hexahydrate
99.99%͒, indium sulfate monohydrate ͑99.99ϩ%͒, lithium chloride
99%͒, potassium chloride ͑99ϩ%͒, sulfur ͑99.998%͒, selenium
99.99ϩ%͒, and strontium chloride hexahydrate ͑99%͒ were from
There is current interest in ternary sulfides for a range of appli-
cations, especially for their luminescent properties.4 These mate-
rials are usually prepared by firing intimate mixtures of the metal
carbonates, oxides or sulfides, and the required activator in a hydro-
gen sulfide atmosphere. Specifically, barium zinc sulfide has been
synthesized by firing a mixture of barium oxide and zinc oxide
under a hydrogen sulfide atmosphere.13 Its luminescent properties
when activated by manganese͑II͒ have been reported in the
-12
͑
͑
͑
1
4,15
literature.
Previously the ternary sulfides containing group I and
Aldrich Chemical Co., and gallium oxide was from Rhone Poulenc.
All chemicals were used without further purification.
group II metals have been prepared by the reaction of metal carbon-
1
6
ate with sulfur at elevated temperatures in an inert atmosphere.
The sulfides of group I and group II metals are water soluble. Upon
addition of sulfur solutions in hydrazine monohydrate, such metals
do not completely precipitate as sulfides from aqueous solutions. In
order to apply the hydrazine monohydrate/sulfur route to multimetal
sulfide production involving metals of group I and group II, it is
necessary to precipitate these metals fully from solution when the
other components ͑of the desired ternary sulfide͒ are precipitated.
Therefore, we investigated modification of the hydrazine
monohydrate/sulfur route by the inclusion of carbonate ͑in the form
of ammonium carbonate͒ as a precipitating anion for group I and
group II metals. The carbonates can then react ͑during firing͒ with
the excess sulfur ͑inherent in or added to the precipitate͒ and other
metal sulfides.
Precipitation methods.—The general synthetic route for
the preparation of unfired M Ga S :activator ͑where
II
II
M
2
4
ϭ Sr, Ca, Zn) was as follows.
Gallium chloride solution ͑1 M͒ was prepared by dissolving gal-
lium oxide in the minimum volume of hot concentrated hydrochloric
acid, which was then allowed to cool to room temperature and di-
luted to the required molarity with distilled water. To this was added
II
an aqueous solution of the M metal salt ͑0.5 M͒ and the activator
metal salt ͑transition or rare earth element͒. ͑In the case of strontium
thiogallate doped with cerium, the codopant was added as well.͒
Separately, sulfur was added very slowly, with stirring, to hydrazine
monohydrate. Once the sulfur had dissolved, the resulting dark red/
brown solution ͑the color of which is due to the presence of polysul-
1
The versatility of solutions of sulfur or selenium in hydrazine
monohydrate in the preparation of an extensive range of ternary
chalcogenides are described. Here, the syntheses of the following
fide species present in solution ͒ ͑5 M͒ was gravity filtered and the
II
filtrate added directly dropwise to the stirring aqueous M /gallium/
activator solution. Precipitation occurred immediately. After the ad-
dition of the sulfur solution, aqueous ammonium carbonate solution
͑0.5 M͒ was added to the reaction mixture and stirring was contin-
ued for a further 30 min. The precipitate was filtered off, washed
thoroughly with isopropanol, and air dried.
*
Electrochemical Society Active Member.
E-mail: j.silver@greenwich.ac.uk
z
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D90
Journal of The Electrochemical Society, 148 ͑7͒ D89-D93 ͑2001͒
The synthesis of unfired barium zinc sulfide:manganese was by
the same method except aqueous solutions of barium acetate ͑1.5 M͒
and zinc acetate dihydrate ͑0.75 M͒ were used. The concentration of
aqueous ammonium carbonate solution was 0.75 M.
CuCrS was also prepared by the sulfur/hydrazine monohydrate
2
method from aqueous solutions of copper chloride ͑0.25 M͒ and
chromium chloride ͑0.25 M͒. There was no addition of ammonium
carbonate in this precipitation.
CuInS2 and CuInSe2 were produced in a similar manner to
CuCrS . The concentration of sulfur or selenium ͑as appropriate͒
2
dissolved in hydrazine monohydrate was 4 M, and aqueous solutions
of copper acetate ͑0.25 M͒ and indium sulfate ͑0.25 M͒ were used.
There was no addition of ammonium carbonate in these two prepa-
rations.
Firing methods.—The ternary sulfides were then fired in an ar-
gon atmosphere. In the case of the thiogallates, additional powdered
sulfur ͑equal quantity by weight͒ was added to the unfired material
to prevent and/or deter oxidation. Both strontium thiogallate with
cerium as the activator and calcium thiogallate:europium were fired
at 800°C for 60 min. Strontium thiogallate:europium, and barium
zinc sulfide:manganese were fired at 850°C for 60 min. Zinc thiogal-
late:manganese was fired at 1000°C for 30 min. Copper indium
disulfide and copper indium diselenide were both fired at 900°C for
Figure 1. Scanning electron micrograph of unfired SrGa S :Eu.
2
4
Luminescent materials.—(1) Strontium thiogallate:europium
Sr0.97Ga S :Eu0.03).—The preparation of strontium thiogalla-
(
1
h.
Experimental spectroscopic techniques.—The M o¨ ssbauer spectra
were recorded at 77 K. The apparatus and methodology have been
2 4
te:europium was initially carried out without the addition of the
aqueous solution of ammonium carbonate. The X-ray diffraction
͑XRD͒ powder data of the fired precipitate prepared in this way
2
8
29
described previously. Raman spectra were obtained using a La-
bram Raman spectrometer equipped with an 18800 g/mm holo-
graphic grating, using a holographic supernotch filter and a Peltier-
cooled change-coupled device detector. Samples were excited using
a helium-neon laser with an output 8 nW of power at the sample on
the 632.8 nm line. Luminance was observed using infrared excita-
tion using a Spex Triplemate Raman spectrometer equipped with an
intensified photodiode array detector. The infrared excitation was
provided by a 3900 nm titanium-sapphire laser ͑Spectra Physics͒
pumped by an intracavity frequency doubles Nd:yttrium-aluminum-
garnet ͑YAG͒ laser ͑Spectra Physics͒; the laser power varied be-
tween 20 and 50 mW at the sample. X-ray powder diffraction pat-
terns were recorded using a PW1729 X-ray generator, PW1710
diffractometer control, and a PM8203A on-line recorder X-ray pow-
der diffraction spectrometer. The data was compared with known
X-ray powder diffraction patterns.29 Scanning electron microscopy
showed the presence of both SrGa S ͑JCPDS no. 25-895͒ and
2
4
29
Ga S ͑JCPDS no. 16-500͒. The luminescence was inferior to that
2
3
of fired strontium thiogallate:europium that had ammonium carbon-
ate added during the preparation ͑see below͒. When aqueous ammo-
nium carbonate solution ͑0.5 M͒ was added to the filtrate from the
above reaction mixture after the precipitate had been filtered off, a
white solid precipitated. The XRD powder data showed that this was
29
SrCO ͑JCPDS no. 5-418͒ confirming that in the absence of am-
3
monium carbonate group I and group II metal sulfide precipitation is
incomplete. The white solid was fired at 900°C with additional sul-
fur. The body color was white. The XRD powder data of the fired
29
material showed the presence of SrS ͑JCPDS no. 8-489͒ The fired
material displayed patchy red luminescence under 366 nm UV ex-
3ϩ
citation, indicating the presence of SrS:Eu . This also indicates
that if some europium ions remain in solution after the addition of
the hydrazine monohydrate/sulfur solution than they are present as
͑
SEM͒ studies were carried out using a Cambridge Instruments Ste-
3ϩ
Eu
.
reoscan 90 scanning electron microscope. Photoluminescence emis-
sion spectra were measured using a Bentham Tel301D detector,
DMC3B programmable monochromator control, M300 monochro-
mator, and a 228A programmable current amplifier linked to a PC.
Excitation was achieved using a 366 nm wavelength light.
The preparation of strontium thiogallate:europium was then ac-
complished with the addition of an aqueous solution of ammonium
carbonate. There was some evidence from the XRD powder data in
29
the unfired material of the presence of sulfur ͑JCPDS no. 8-247͒,
due to the excess of sulfur used during the precipitation reaction.
Otherwise, the XRD powder data of the material consisted of a
broad peak. It was only upon firing that the XRD powder data indi-
cated the presence of crystalline strontium thiogallate in accord with
Results and Discussion
2
9
JCPDS no. 25-895. SEM studies showed that the unfired material
consisted of agglomerates, ϳ200 nm diam. These smaller particles
themselves agglomerated to form larger structures ͑Fig. 1͒. The fired
material was made up of irregular agglomerates of crystals of vary-
ing size ͑ϳ1-5 ␮m͒, and also where the firing was performed in the
presence of additional sulfur, there were needle shaped sulfur crys-
tals present ͑Fig. 2͒, which were then removed by Soxhlet extraction
using carbon tetrachloride as the solvent. The body color of the fired
material was yellow.
In this investigation we have concentrated on photoluminescent
PL͒ measurements which yield the color purity of the emission,
͑
allowing the selection of potentially useful phosphors for further
studies. A common problem encountered with sulfide containing
phosphors for cathodoluminescent ͑CL͒ measurements is that they
slowly degrade under electron beam bombardment to produce off
products that corrode the inside of the measuring equipment. This
limits the characterization which can be carried out on these mate-
rials without incurring excessive expenditure.
The fired material displayed green photoluminescence under 366
nm UV excitation ͑Fig. 3a͒. CIE coordinates: x ϭ 0.2728, y
ϭ 0.6843. ␭max ϭ 534 nm. The PL CIE values of this material are
in very good agreement with the CL CIE values of SrGa2S4 :Eu
prepared firing intimate mixtures of carbonates and oxides under
The following five phosphors were prepared utilizing the addi-
tion of ammonium carbonate solution to completely precipitate the
metal salts present. Sulfur was added to the precipitate for firing to
deter oxidation and to react with group I and group II carbonates to
form sulfides. CuCrS , CuInS , and CuInSe were prepared without
2
2
2
4
using ammonium carbonate during the precipitation stage, or sulfur
before the firing stage.
H2S gas. The color of the emission shows that, although the mate-
3
ϩ
rial was prepared from an Eu salt, the resulting phosphor contains
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Journal of The Electrochemical Society, 148 ͑7͒ D89-D93 ͑2001͒
D91
Figure 2. Scanning electron micrograph of fired SrGa S :Eu.
2
4
Eu2 as desired. However, it must be noted that the sulfur/hydrazine
ϩ
3
ϩ
monohydrate did not fully accomplish the reduction of Eu to
2
ϩ
Eu . This is usually achieved by firing under a reducing H S
2
atmosphere.4
,7,11
The presence of the remaining Eu was detected
3ϩ
using both M o¨ ssbauer spectroscopy and a new diagnostic method
which we will describe in full elsewhere.3
0,31
This involves the use
of a two photon upconversion method utilizing the 632.8 nm line of
a He/Ne laser. Characteristic emission around 700 nm ͑Fig. 4͒ sig-
3
ϩ
5
7
nifies the presence of Eu , and arises from the D to F transi-
0
4
tions. This finding of Eu3 signifies that the phosphor needs to be
ϩ
fired in a reducing atmosphere for optimum performance.
Thus, in the absence of ammonium carbonate, strontium salt pre-
cipitation will be incomplete, giving rise to a deficit of strontium
ions in the precipitated precursor. After firing, this resulted in the
formation of nonluminescent gallium sulfide in addition to the stron-
tium thiogallate phosphor, and thus, the inferior photoluminescence
observed in the absence of ammonium carbonate precipitation.
(
2) Strontium thiogallate:cerium, sodium (Sr0.985Ga S :Ce
,
0.015
2
4
Na0.015).—The XRD powder data of the unfired material indicated
29
some evidence of sulfur ͑JCPDS no. 8-247͒ but otherwise the
material consisted of a broad peak, possibly indicating some pre-
liminary ordering, but indicating that much of the precipitated ma-
terial was closer to amorphous than crystalline. After firing, the
XRD powder data showed the presence of strontium thiogallate
2
9
͑
͑
JCPDS no. 25-895͒, but additionally there was evidence of Ga O
2 3
JCPDS no. 11-370͒29 as a minor constituent of the fired material.
The morphology of both the unfired and fired particles were very
similar in appearance to the particles of the europium doped stron-
tium thiogallate both before and after firing. Needle shaped crystals
of sulfur were also present, which were removed by Soxhlet extrac-
tion using carbon tetrachloride as the solvent. The body color of the
fired material was white.
The fired material displayed blue luminescence under 366 nm
UV excitation ͑Fig. 3b͒. The CIE coordinates are x ϭ 0.2267 and
y ϭ 0.1862. ␭max ϭ 445 nm. Comparison of the PL CIE coordi-
nates of this phosphor with the CL coordinates of SrGa S :Ce,Na
2
4
͑
Ce concentration ϭ 0.6%) prepared by solid-state synthesis under
9
a H S gas atmosphere indicate that the emission color of the phos-
2
phor produced in this investigation was greener than that of the
phosphor reported in the literature. The difference in CIE coordi-
nates may simply be due to the difference in cerium concentrations.
Altering the activator concentration has a noticeable effect on the
9
chromaticity of the phosphor. It may also be noted that the ␭max of
Figure 3. Photoluminescence spectra ͑366 nm excitation͒ of ͑a͒
SrGa S :Eu, ͑b͒ SrGa S :Ce,Na, ͑c͒ ZnGa S :Mn, ͑d͒ CaGa S :Eu, and ͑e͒
Ba ZnS :Mn.
2 3
the phosphor prepared in this work matches the CL ␭
value re-
max
2
4
2
4
2
4
2 4
ported by Peters and Baglio4 for SrGa S :Ce,Na. They did not,
2
4
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D92
Journal of The Electrochemical Society, 148 ͑7͒ D89-D93 ͑2001͒
Figure 4. Stokes emission arising from the two photon upconversion of the
6
32.8 nm line of He/Ne laser. The emission peaks around 690 to 712 nm are
3
ϩ
diagnostic of Eu
.
Figure 5. Scanning electron micrograph of fired CuInS2.
however, report the concentration of cerium used. Sodium, added as
sodium chloride, was the preferred codopant. Replacement with am-
monium chloride, lithium chloride, potassium chloride, or cesium
chloride resulted in inferior luminescence under 366 nm UV excita-
tion. The performance of the other codopants were in the order
wise consisted of a broad band, again indicating possibly some short
range order. The XRD powder data of the fired material indicated
the presence of a mixture of the ␣ and ␤ phases of zinc sulfide,
29
JCPDS no. 5-566 and 36-1450, respectively. The fired material
displayed orange-yellow luminescence under 366 nm UV excitation,
which was indicative of zinc sulfide:manganese. As with the stron-
tium thiogallate:europium, an aqueous solution of ammonium car-
bonate ͑0.75 M͒ was added to the filtrate. A white solid precipitated
from the filtrate. The XRD powder data of this precipitate consisted
ϩ
ϩ
ϩ
ϩ
ϩ
Li Ͼ NH4 Ͼ K Ͼ Cs . It would appear that the radius of Na
ϩ
was a good match to the lattice in size whereas Li was too small
ϩ
4
ϩ
ϩ
and NH , K , and Cs were all too large.
(
3) Zinc thiogallate:manganese (Zn0.98Ga S :Mn0.02).—Particles of
2 4
of BaCO ͑JCPDS no. 5-0378͒.
3
the thiogallate before and after firing were similar in appearance to
the particles of the europium doped strontium thiogallate. Again,
after firing, there were needle shaped crystals of sulfur present. The
body color of the fired material was white. The fired material dis-
played red luminescence under 366 nm UV excitation ͑Fig. 3c͒. The
CIE coordinates are x ϭ 0.6661 and y ϭ 0.3331. ␭max ϭ 653 nm.
Nonluminescent materials.—(6) Copper chromiuum disulfide
(CuCrS2).—Ammonium carbonate addition was not required for the
complete precipitation of the metal ions in the unfired material as
transition metal sulfides are insoluble in aqueous solutions. The
XRD powder data of the unfired material indicated the presence of
2
9
sulfur ͑JCPDS no. 8-247͒. The XRD powder data of the fired
29
(
4) Calcium thiogallate:europium (Ca0.8Ga S :Eu0.2).—As with the
2 4
material were consistent with that of CuCrS ͑JCPDS no. 23-952͒.
2
strontium thiogallate, the XRD spectrum of the unfired material con-
sisted of a broad peak. The XRD powder data of the fired material
The aim here was to demonstrate that ternary transition metal sul-
fides may be readily synthesized by the unmodified hydrazine
monohydrate route when group I and group II metals are not
present.
2
9
showed the presence of calcium thiogallate ͑JCPDS no. 25-134͒.
The unfired material consisted of agglomerates similar in appear-
ance to the unfired strontium thiogallate, and the fired material ap-
peared as irregular agglomerates. The body color of the fired mate-
rial was yellow. The fired material displayed yellow luminescence
under 366 nm UV excitation ͑Fig. 3d͒. The CIE coordinates are
x ϭ 0.3908 and y ϭ 0.6031. ␭max ϭ 555 nm. The ␭max value
(
7) Copper indium disulfide (CuInS ).—Addition of ammonium car-
2
bonate was not required to achieve complete precipitation of the
unfired material due to the insolubility of the sulfides of copper and
indium in aqueous media. Both the precipitated material and the
fired material were black solids. The fired material ͑Fig. 5͒ consisted
of irregular agglomerated crystals of varying size ͑ϳ1-5 ␮m͒. The
XRD powder data of the fired material was consistent with that of
matches that reported by Tagiev et al. in PL studies for this
phosphor.8
2
9
(
5) Barium zinc sulfide:manganese (Ba Zn0.985S3 :Mn0.015).—The
CuInS ͑JCPDS no. 27-159͒. The aim of this synthesis was to
2
2
XRD powder data of the unfired material showed the presence of
illustrate that main group metal sulfides may be readily prepared by
the unmodified hydrazine monohydrate route, and may be a suitable
method for making the precursor material for thin film deposition.
29
BaCO ͑JCPDS no. 5-0378͒. The XRD powder data of the fired
3
material indicated the presence of barium zinc sulfide ͑JCPDS no.
29
3
3-189͒,29 barium sulfide ͑JCPDS no. 8-454͒, and sulfur ͑JCPDS
2
9
(8) Copper indium diselenide (CuInSe2).—As with copper chro-
mium disulfide and copper indium disulfide, addition of ammonium
carbonate was not required to achieve complete precipitation of the
unfired material. The fired material was a black solid ͑Fig. 6͒ con-
sisting of agglomerated crystals of varying size ͑1-5 ␮m͒. The XRD
powder data was in good agreement with known values for copper
no. 8-247͒. The unfired barium zinc sulfide also consisted of small
agglomerates, similar to those for the unfired thiogallates described
above. The fired material consisted of irregular agglomerated crys-
tals of varying size ͑ϳ1-5 ␮m͒. The body color of the fired material
was pinkish-white. The optimum mole percentage of manganese
was 1.5% compared to the number of moles of zinc used. The fired
material displayed red luminescence under 366 nm UV excitation
2
9
indium diselenide ͑JCPDS no. 23-209͒. The synthesis of CuInSe2
demonstrates that the unmodified hydrazine monohydrate route is
suitable for the preparation of ternary selenides, which can be used
as precursors for thin film deposition.
͑
Fig. 3e͒. CIE coordinates: x ϭ 0.6671, y ϭ 0.3382. ␭max ϭ 637
nm.
The preparation of barium zinc sulfide:manganese was attempted
without the addition of an aqueous solution of ammonium carbon-
ate. The XRD powder data of the unfired material indicated the
presence of sulfur ͑JCPDS no. 8-247͒.29 The XRD spectrum other-
The role of ammonium carbonate in the synthesis of alkali earth
ternary sulfides.—In the case of group I and group II ternary sul-
fides, it has been demonstrated here that ammonium carbonate ad-
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Journal of The Electrochemical Society, 148 ͑7͒ D89-D93 ͑2001͒
Acknowledgments
D93
The authors would like to thank DARPA and the EPSRC ͑ROPA
grant no. GR/M 78847͒ for part funding this work, Philip Titler for
the M o¨ ssbauer measurements, and David Nicholas for useful discus-
sions concerning the XRD powder data.
The University of Greenwich assisted in meeting the publication costs of
this article.
References
1
2
. D. A. Davies, A. Vecht, J. Silver, P. J. Marsh, and J. A. Rose, J. Electrochem. Soc.,
47, 765 ͑2000͒.
1
. D. A. Davies, A. Vecht, J. A. Rose, P. J. Marsh, C. S. Gibbons, J. Silver, D.
Morton, S. Blomquist, and R. Ravihandren, SID Dig., 30, 1018 ͑1999͒.
. A. Vecht, D. A. Davies, and D. W. Smith, Mater. Res. Innovations, 2, 176 ͑1998͒.
. T. E. Peters and J. A. Baglio, J. Electrochem. Soc., 119, 230 ͑1972͒.
. T. E. Peters, J. Electrochem. Soc., 119, 1720 ͑1972͒.
3
4
5
6
7
. A. Garcia, C. Fouassier, and P. Dougier, J. Electrochem. Soc., 129, 2064 ͑1982͒.
. M. R. Davolos, A. Garcia, C. Fouassier, and P. Hagenmuller, J. Solid State Chem.,
8
3, 316 ͑1989͒.
8
. B. G. Tagiev, M. G. Shakhtakhtinskii, V. A. Dzhalilov, T. A. Gyul’malyev, B. M.
Izzatov, G. K. Aslanov, O. B. Tagiev, and Ya. G. Talybov, Inorg. Mater. (Transl.
of Neorg. Mater.), 29, 1392 ͑1993͒.
Figure 6. Scanning electron micrograph of fired CuInSe2.
9. F.-L. Zhang, S. Yang, C. Stoffers, J. Penczek, P. N. Yocom, D. Zaremba, B. K.
Wagner, and C. J. Summers, Appl. Phys. Lett., 72, 2226 ͑1998͒.
1
1
0. A. N. Georgobiani, B. G. Tagiev, O. B. Tagiev, and B. M. Izzatov, Inorg. Mater.
(
Transl. of Neorg. Mater.), 31, 19 ͑1995͒.
1. L. Eichenauer, B. Jarofke, H.-C. Mertins, J. Dreyhsig, W. Busse, H.-E. Gumlich, P.
B e´ nalloul, C. Barthou, J. Beno ˆı t, C. Fouassier, and A. Garcia, Phys. Status Solidi A,
dition is necessary to ensure the complete precipitation of all the
required cations, as sulfides of these metals are soluble in water. In
the study involving the synthesis of SrGa S :Eu without ammonium
153, 515 ͑1996͒.
12. W. L. Warren, K. Vanneusden, M. A. Rodriguez, C. H. Seager, D. R. Tallant, P. D.
Rack, P. H. Holloway, B. K. Wagner, C. J. Summers, and P. N. Yocom, Appl.
Phys. Lett., 70, 478 ͑1997͒.
2
4
carbonate addition, there was incomplete precipitation of strontium
1
3. R. Hoppe, Angew. Chem., 11, 457 ͑1959͒.
ions, while in the case of the synthesis of Ba ZnS :Mn without
14. A. Vecht, J. Vac. Sci. Technol., 10, 789 ͑1973͒.
2
3
1
1
5. A. C. Newport, A. Vecht, P. A. Bayley, and W. A. Crossland, SID Dig., 29, 239
1998͒.
6. P. K. Ghosh and B. Ray, Prog. Cryst. Growth Charact., 25, 1 ͑1982͒, and refer-
ammonium carbonate addition, there was no evidence for the pres-
ence of barium cations in the fired material. The precipitated car-
bonates are converted into sulfides during the firing process by the
reaction with excess sulfur that is present in the precipitate and
added to the firing mixture.
We believe that the method will prove most useful, not only in
the synthesis of cathodoluminescent and electroluminescent binary
and ternary compounds, but also in the synthesis of a large range of
semiconductor materials, particularly those used in photovoltaic de-
vices.
͑
ences therein.
17. F. O. Adurodija, J. Song, S. D. Kim, S. K. Kim, and K. H. Yoon, Jpn. J. Appl.
Phys., 37, 4248 ͑1998͒.
1
8. H. J. Lewrenz, K. D. Hausemann, M. Kunst, H. Golowsky, S. Fiechter, and H.
Neff, J. Mater. Sci., 21, 4419 ͑1986͒.
1
9. T. Yukawa, K. Kuwabara, and K. Kuomoto, Thin Solid Films, 286, 151 ͑1996͒.
20. R. Nomura, Y. Seki, K. Konishi, and H. Matsuda, Appl. Organomet. Chem., 6, 685
1992͒.
͑
2
2
1. R. Nomura, Y. Seki, and H. Matsuda, J. Mater. Chem., 2, 765 ͑1992͒.
2. M. Jayachandran, M. J. Chockalingham, K. R. Murali, and A. S. Lakshmanan,
Mater. Chem. Phys., 34, 1 ͑1993͒.
2
3. J. R. Woodyard and G. A. Landis, Sol. Cells, 31, 297 ͑1991͒.
Conclusions
24. R. W. Birkmire and E. Eser, Annu. Rev. Mater. Sci., 27, 625 ͑1997͒.
2
2
5. K. Rajeshwar and N. R. de Tacchoni, Stud. Surf. Sci. Catal., 103, 321 ͑1997͒.
6. O. Savadogo, Sol. Energy Mater. Sol. Cells, 52, 361 ͑1998͒.
It has been shown that an extensive range of ternary chalco-
genides may be successfully prepared by the hydrazine
monohydrate/sulfur method. Preparation of transition metal and/or
main group metal chalcogenides may be readily synthesized by this
method. Ternary chalcogenides containing group I or group II met-
als require the use of ammonium carbonate as a precipitating agent.
The hydrazine monohydrate/sulfur route for materials prepared pro-
vides a clean method that eliminates most sulfurous gas emission.
The method is simple to perform and rapid to use. For laboratory
preparations the materials can be prepared in approximately 5 h.
27. R. P. Raffaelle, H. Forsell, T. Potdevin, R. Friedfield, J. G. Mantovani, S. G.
Bailey, S. M. Hubbard, E. M. Gordon, and A. F. Hepp, Sol. Energy Mater. Sol.
Cells, 57, 162 ͑1999͒.
2
2
8. J. Ovenstone, P. J. Titler, R. Withnall, and J. Silver, J. Phys. Chem. B, In press.
9. W. F. McClune, Powder diffraction file. Inorganic Phases, JCPDS-International
Centre for Diffraction Data, Swarthmore, PA, USA ͑1983͒.
3
3
0. J. Silver, M. I. Martinez-Rubio, T. G. Ireland, G. R. Fern, J. Ovenstone, and R.
Withnall, in Proceedings of the 6th International Conference Phosphors and Dis-
play Technology, Nov 6-8, 2000.
1. J. Silver, R. Withnall, A. Newport, M. I. Martinez-Rubio, T. G. Ireland, P. J.
Marsh, and A. Vecht, SID Digest, In press.
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