Existence of off-stoichiometric single phase kesterite

Journal of Solid State Chemistry

Hoelzel

Lerch

2016

In this work a series of stoichiometric Cu 2 ZnSnS 4 (CZTS) samples annealed at different temperatures in the range of 473 -623 K were investigated. The temperature dependence of the Cu/Zn-orderdisorder behavior was analyzed by neutron powder diffraction measurements. Cu fully occupies the 2a and Sn the 2b position within the whole temperature range. For Zn and the remaining Cu on sites 2d and 2c, a clear change from ordered to disordered kesterite structure is found. The critical temperature T c for this Landau-type second order transition was determined as 552 ± 2 K. It was found that in Cu 2 ZnSnS 4 very long annealing times are necessary to reach equilibrium at low temperatures.

Section: Resultsmentioning

confidence: 99%

The order-disorder transition in Cu2ZnSnS4 – A neutron scattering investigation

Journal of Solid State Chemistry

Hoelzel

Lerch

2016

“…The Cu/(Zn+Sn) and Zn/Sn ratio of the single phase CZTS sample were determined as 1.00 and 1.03, respectively, thus by taking into account the measurement error of the microprobe system the sample can be considered as stoichiometric, perhaps with a tendency of Zn excess resulting in a slight B-type off-stoichiometry ( Figure 5). These off-stoichiometric models were first introduced in [31] and extended by [32]. Finally the integral chemical composition can be calculated as Furthermore, phase purity was investigated by XANES.…”

Section: Chemical Composition and Phase Puritymentioning

confidence: 99%

A mechanochemical route to single phase Cu2ZnSnS4 powder

Journal of Alloys and Compounds

Just

Dolotko

et al. 2016

With respect to absorber materials in solar cells, Cu 2 ZnSnS 4 (CZTS) has been a focus of interest in recent years. In this work, a new route leading to single phase CZTS powders is presented. For structural characterization X-ray and neutron powder diffraction measurements were performed. Further structural and compositional analysis of the CZTS powder was carried out by means of X-ray absorption near edge spectroscopy (XANES) and wavelengthdispersive X-ray spectroscopy (WDS). The obtained CZTS powder with an actual composition of Cu 2.00(4) Zn 1.02(2) Sn 0.99(2) S 4.00(8) adopts the kesterite-type structure. A detailed cation distribution analysis using the average neutron scattering length method revealed a partial disorder of copper and zinc on the (2c) and (2d) sites.

“…For CZTS it is known that intrinsic defects can be easily formed while the kesterite-type structure (space group I4) is maintained, e.g. [17,[24][25][26]. Theoretical work [14,27] has shown that the defect cluster [Zn 2À Sn + Sn…”

Section: Resultsmentioning

confidence: 99%

“…Due to the formation of secondary phases it is challenging to prepare phase-pure CZTS powder, which is important for detailed studies concerning the correlations between structural and electronic properties. Bulk material of CZTS has been usually produced by solid state reaction of the elements in evacuated silica ampoules [1,17]. Due to the high sulfur vapor pressure it is necessary to apply a well-defined temperature program and homogenization is achieved by a second annealing step at 750 C. All these factors result in long reaction times and an enhanced possibility for the formation of secondary phases.…”

Section: Introductionmentioning

confidence: 99%

Study of the mechanochemical process to crystalline Cu 2 ZnSnS 4 powder

Materials Research Bulletin

Schlösser

Pfitzner

et al. 2016

A B S T R A C TKesterite-type Cu 2 ZnSnS 4 was synthesized from the corresponding binary sulfides by a mechanochemical route in a planetary ball mill. The reaction progress during this milling step was followed within a time range of 10-180 min by powder X-ray diffraction. In addition, the crystallization of the milled material was studied in situ by high-temperature X-ray diffraction methods in the temperature range of 300-500 C. Significant disorder (cation distribution) was observed at 500 C, strongly decreasing during cooling down to ambient temperature with a rate of 60 K/h.