Imidazolium ionic liquid has been prepared from 1-methylimidazolium as a substrate. The work includes specific basic characterization of a synthesized compound by NMR spectra, water content, and a glass transition temperature determined by the differential scanning calorimetry (DSC). The mutual solubilities of 1-hexyl-3-methylimidazolium thiocyanate, [HMIM][SCN], with water, alcohols, n-alkanes (n-hexane, n-heptane, n-octane, n-nonane, or n-decane), aromatic hydrocarbons (benzene, toluene, or ethylbenzene), and cyclic hydrocarbons (cyclohexane or cycloheptane) have been measured at ambient pressure by a dynamic method in a range of temperatures from (200 to 420) K. The simple eutectic system was observed for water with complete miscibility in the liquid phase. Complete miscibility has been observed in the systems of [HMIM][SCN] with alcohols ranging from methanol to 1-decanol at a temperature of T = 298.15 K. The upper critical solution temperatures (UCSTs) were observed for the systems with n-alkanes and the lower critical solution temperatures (LCSTs) for the systems with aromatic hydrocarbons. The solubility decreases with an increase of the molecular weight of the solvent. The liquid−liquid phase equilibria (LLE) have been correlated using the nonrandom two-liquid (NRTL) equation. The average root-mean square deviation of the equilibrium mole fraction for all of the LLE data was 0.0021.

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This paper aims at providing an updated overview of the main achievements in the development of solar cells based on Cu 2 ZnSn(S,Se) 4 (CZTS(Se)) Kesterite absorbers obtained by electrodeposition. Although undoubtedly challenging, the ultimate goal is to learn from the past works and build a solid framework for future advances in this field. What is the reason for the lower efficiency of electrodeposited CZTS(Se)-based devices (8%) compared to the world record efficiency achieved with a hydrazine-based solution approach (12.6%)? Can this gap be filled, or there are intrinsic limitations for this achievement? The review is divided into the three main electrodeposition approaches: sequential elemental layer, alloy co-deposition, and chalcogenide co-deposition. It is argued that considerable technical challenges must be overcome for the latter approach to be successfully applied.Plot of the record power conversion efficiencies of Kesterite sulfide-based solar cells obtained by electrodeposition (hollow dots), and world record efficiency of CZTS(Se)-based devices (full dots). The dashed line shows the 15% minimum efficiency threshold considered relevant for potential industrial application.

Activity coefficients at infinite dilution (γ 13 ∞ ) for 34 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, acetone, and water in the ionic liquid 1-hexyl-3-methylimidazolium thiocyanate ([hmim][SCN]) were determined by gas-liquid chromatography over temperature range from (298.15 to 368.15) K. The partial molar excess enthalpies at infinite dilution values (∆H 1 E,∞ ) were calculated from the experimental γ 13 ∞ values, obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbon separation problems were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids with a thiocyanate-based anion or a sCtN group in an anion or a cation, N-methyl-2pyrrolidinone (NMP) and sulfolane.

The EQE can be simulated from EQE R taking into account the filtering of photons through ZnSe and the collection losses of charge carriers in the absorber layer underneath ZnSe. To consider the collection losses it is necessary to compute the total volume of absorber layer underneath ZnSe and the fraction of it which is still subject to carrier collection.

A B S T R A C TBand tailing is a major contributing factor to the large open circuit voltage (V oc ) deficit that is currently limiting Cu 2 ZnSnS 4 (CZTS) photovoltaic devices. It occurs in highly doped, highly compensated semiconductors and gives rise to a non-uniform electronic band structure. Here we report spatially resolved fluctuations in CZTS optical properties using low temperature cathodoluminescence (CL) in a scanning electron microscope (SEM). Principal component analysis reveals three CL peaks whose relative intensity vary across domains~100 nm in size. It is not known whether the non-uniform optical properties are due to changes in composition or due to structural order-disorder at constant composition. Measurement of composition with energy dispersive X-ray (EDX) analysis in an SEM and ordering with Micro-Raman mapping revealed CZTS to be uniform within the spatial resolution (estimated at~0.4 µm and 1.1 µm respectively) and sensitivity of the two techniques. The CL results are consistent with the presence of band tailing in CZTS.

Cu2ZnSnSe4 p-type semiconductors currently investigated for use in thin film solar cells can be synthesized by firstly depositing a metallic precursor and secondly annealing the precursor in selenium vapor. Differently stacked Cu-Sn-Zn metallic precursors were characterized after a soft annealing at 350°C under nitrogen atmosphere. For the stack where the Sn and Zn were in direct contact with sufficient Cu to form a stable alloy, a bi-layered structure consisting of Cu-Sn on the bottom and Cu-Zn on the top was formed. Contrarily, when Zn was not in direct contact with Cu, the metals diffused to form a stable alloy and the system segregates horizontally, forming a mixed columnar structure. These two types of precursors were selenized under exactly the same conditions to form kesterite absorbers for solar cell devices. Using this approach the improvement from 0.44% power conversion efficiency for the bi-layered precursor to 4.5% for the mixed precursor was achieved.