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We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach which includes the deposition of precursor films by the magnetron sputtering method at room temperature followed by selenization of the precursor films at 560∘C. Formation of CZTSSe films with the kesterite structure was confirmed by XRD and Raman spectroscopy analyses. The films are slightly Cu-rich and Zn-deficient. SEM study shown that the films have uniform surface morphology and densely packed structure without any voids and cracks. [ABSTRACT FROM AUTHOR]

[Display omitted] • A MEA-DMF based S free solution for preparing CZTSe was successfully developed. • Phase evolution of CZTSe thin film during selenization was studied. • A device efficiency of 7.53% was obtained by using the MEA-DMF solution method. Most precursor solutions for preparing Cu 2 ZnSn(S,Se) 4 thin films use sulfur containing groups to complex metal ions. However, solutions with sulfur containing groups are always toxic and harmful gases, such as H 2 S and SO x , will be released when drying precursor films. Based on the excellent chelating ability of ethanolamine, a stable molecular precursor solution without using sulfur based complexing agent was successfully developed. Cu-Sn alloy phase is formed in the precursor film, which makes the phase evolution of the absorber during selenization similar to that of Cu 2 ZnSnSe 4 film grown from metallic precursor. Impacts of selenization time on compositional, morphological and photovoltaic properties of the Cu 2 ZnSnSe 4 film were studied. Finally, a Cu 2 ZnSnSe 4 solar cell with conversion efficiency of 7.53% was obtained by using the ethanolamine-dimethyl formamide based solution. [ABSTRACT FROM AUTHOR]

In this study, we proposed a 4-step selenization process for the RF-sputtered Cu–Zn/Sn metallic stack to prepare Cu 2 ZnSnSe 4 (CZTSe) absorber. We applied a pre-heating treatment for the metal stack under vacuum prior to the selenization, which plays an important role to form a well inter mixed alloy with relatively smooth thin film morphology. The nucleation temperatures were controlled precisely from 150 °C to 500 °C during 4-step selenization to avoid the formation of secondary phases and to improve the crystal quality of CZTSe with a greater homogeneity in the composition. The formation of various phases during each step in 4-step selenization process were studied by X-ray Diffraction, Raman analysis and we proposed a possible reaction mechanism of the CZTSe formation with binary and ternary compounds as intermediates. We also performed optical analysis, including Uv–Visible absorption and low temperature photoluminescence, and scanning transmission electron microscope analysis for the CZTSe samples. Finally, an efficiency of 5.8% CZTSe solar cell is fabricated with an open circuit voltage of 370 mV, short circuit current of 31.99 mA/cm 2 , and a fill factor of 48.3%. [ABSTRACT FROM AUTHOR]

The range of applications for kesterite photovoltaic devices can be widely broadened by the use of alternatives to the commonly used soda-lime glass (SLG) as substrate. This work explores the possibility to use commercial ceramic tiles as ecological substrates for Cu 2 ZnSnSe 4 (CZTSe) thin film solar cells in view of an application in building integrated photovoltaics (BIPV). As a novel approach to control the Na-incorporation into the kesterite absorber, the substrates are coated with enamels containing different concentrations of Na 2 O (from 2 to 20% wt.). This way, the enamel becomes not only a smoothing element but also a source of Na during the absorber growth. The impact that an increased Na 2 O content has on the Mo back contact deposited on these enameled ceramic substrates is investigated. 3D optical profilometry shows surfaces with undulations, pinholes and cracks directly related to the Na 2 O content of the enamels. High quality kesterite (Cu 2 ZnSnSe 4 ) absorbers with good crystallinity were produced on these substrates by sequential precursor sputtering and selenization. The good performance of first solar cell devices with a maximum efficiency of 7.5% gives a solid proof-of-concept for ceramic solar tiles based on efficient kesterite absorbers. [ABSTRACT FROM AUTHOR]

Cu–Zn–Sn (CZT) precursors for Cu 2 ZnSnSe 4 (CZTSe) solar cell were prepared by electrochemical co-deposition method with different metals composition. CZT precursors were preliminary annealed in three different atmospheres in order to obtain homogenous, without pores Cu–Zn–Sn layers. A high crystalline quality CZTSe absorber was synthesised as has been determined by X-ray diffraction and Raman spectroscopy methods. CZTSe based solar cells were fabricated and champion cell demonstrated 2.7% efficiency and reached as high as 70% of external quantum efficiency. Scanning electron microscope investigations of CZTSe solar cells cross-section revealed that Mo/CZTSe interface exhibits large voids and local delamination from Mo layer. The back contact issues are detrimental to solar cell performance reducing shunt resistance and open circuit voltage. [ABSTRACT FROM AUTHOR]

Highlights: [•] A promising compression was performed to improve the smoothness and density of CISe and CZTSe films. [•] The effects of annealing atmosphere on the properties of CISe films were investigated. [•] The effect of mechanical pressure on the smoothness and density of the oxides films was demonstrated. [•] The densification mechanism of CISe and CZTSe thin films was also studied. [ABSTRACT FROM AUTHOR]

Cu2ZnSnSe4 solar cells were synthesized by electrodeposition of metal stack precursors followed by selenization, a high potential process for industry, leading to conversion efficiencies above 5%. An additional selenium-capping layer deposited on the precursor before annealing showed improved uniformity and morphology of CZTSe layers compared to other selenization routes. Two different atmospheric annealing systems were used: a closed graphite box in a tubular furnace and a three-chamber dynamic rapid thermal processing furnace. The RTP system gave larger grains and more compact layers, whereas CZTSe selenized in tube furnace had smaller grains and a higher series resistance. Both annealing systems gave best cells power conversion efficiencies over 5%. We will discuss the device photoelectric properties and their relation to material structures and processing. [ABSTRACT FROM AUTHOR]

Cu2ZnSnSe4(CZTSe) films were formulated by the selenization of Cu(Zn, Sn) (CZT) metal precursors. The CZT precursor was prepared by depositing zinc onto a Cu-Sn layer co-sputtered on molybdenum-coated soda-lime glass substrates. Selenium was evaporated thermally onto the CZT precursor. The resulting CZTSe film was then annealed at 450 °C for various annealing times (1, 3, 5, 10 and 15 min) using a rapid thermal process (RTP). Crystallization of the CZTSe film as a function of the annealing time was observed by X-ray diffraction (XRD). The XRD patterns of the films annealed over 3 min were well matched to those of a CZTSe single crystal. The lattice parameters of the CZTSe films annealed over 5 min werea= 5.639 Å andc= 11.356 Å. These values were reasonably close to the lattice parameters of a single crystal of Cu2ZnSnSe4(a= 5.693 Å andc= 11.333 Å). The energy gap of the CZTSe films was 1.14 eV. [ABSTRACT FROM AUTHOR]

Abstract: Polycrystalline Cu2ZnSnSe4 (CZTSe) thin films were prepared by a two-stage process namely thermal evaporation of stacked layers Cu/ZnSe/Sn/Se on soda-lime glass substrates held at different substrate temperatures (T s ) in the range 523–723K followed by annealing the stack in selenium atmosphere at 723K for an hour. The effect of T s on the growth and properties of these films were analyzed by studying their structural, microstructural and optical properties. XRD studies revealed the structure to be kesterite with a=0.569nm and c=1.139nm. Raman spectroscopy is used as a complimentary tool to know the presence of possible secondary phases. The crystallinity of the films improved with increase in the substrate temperature. Spectral transmittance studies of these films revealed two optical transitions with direct band gaps of ∼1.0eV and 1.4eV which are attributed to CZTSe and CZTSe with minor ZnSe, as the annealed stack might be inhomogeneous. [Copyright &y& Elsevier]

Abstract: In this work, we show a set of growth conditions, for the two step process, with which the growth of CZTSe is successful and reproducible. The properties of the best CTZSe thin films grown by this method were examined by SEM/EDS, XRD, Raman scattering, AFM/EFM, transmittance and reflectance measurements, photoluminescence (PL) measurements and hot point probe. A broad emission band was observed in the photoluminescence spectrum of the CZTSe thin film. The band gap energy was estimated to be around 1.05eV at room temperature, using the transmittance and reflectance data, and CZTSe samples show p-type conductivity with the hot point probe. The different characterization techniques show that we could grow single phase CZTSe thin films with our optimized process conditions. [ABSTRACT FROM AUTHOR]

Abstract: Despite the success of Cu(In,Ga)Se2 (CIGS) based PV technology now emerging in several industrial initiatives, concerns about the cost of In and Ga are often expressed. It is believed that the cost of those elements will eventually limit the cost reduction of this technology. One candidate to replace CIGS is Cu2ZnSnSe4 (CZTSe). We report the preliminary results of CZTSe thin films grown on bare and Mo coated glass through selenization of DC magnetron sputtered Cu/Zn/Sn precursor layers in an atmosphere of Se vapour. The influence of the selenization temperature on the resulting films has been studied. The resulting films were studied by SEM/EDS, XRD, and Raman scattering. [Copyright &y& Elsevier]

For the formation of CZTSe films, selenization time and temperature play a crucial role in a material synthesis which in turn highly affects the properties of the films. In this work, Cu, Zn, Sn and Se were thermally-deposited sequentially on Mo coated soda-lime glass (SLG) substrates. For the formation of Cu 2 ZnSnSe 4 (CZTSe) deposited films were annealed in a two-step process (first step 230 °C for 10 min and second step 450 °C for 5 min–30 min with 5 min interval) in Selenium (Se) atmosphere. The effect of selenization time on the structural, surface morphology, compositional, optical and electrical properties of the CZTSe films was studied. The formation of CZTSe phase is observed from XRD and Raman spectra. It was observed that with the increase in selenization time the CuSe binary phase present in the film suppressed gradually. The grain size, conductivity and mobility of the films increase whereas the band gap decreases with the increase in the hold time in the second step of selenization. The selenization time improves the properties of the films which can be suitable for solar cell applications. The study shows that optimum selenization time is essential to get a good quality CZTSe film. The device has been attempted for sample M6 and the best device obtained gives a conversion efficiency of 3.97% Image 1 • Systematic selenization time variation to obtain pure CZTSe. • XRD data at different glancing angle to make sure no binary phase present throughout the film thickness. • Grain growth and its effect on different properties has been discussed with respect to variation in selenization time. • The efficiency of the device obtained using M6 film is 3.97%. [ABSTRACT FROM AUTHOR]