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New synthesis of solution processable kesterite and kesterite-phenoxazine nanopowders were presented. The direct band-gap semiconductor Cu2ZnSnS4 has attracted the attention of many due to its large absorption coefficient (α > 104 cm-1) and (optical) band-gap energy close to the optimal value for solar light conversion (1.4-1.6 eV). The presence of a kesterite nanocrystal structure has been investigated and confirmed by (HR)TEM, X-ray powder diffraction, EDX and EXAFS measurements. Low-temperature photoluminescence (PL) measurements indicate the absence of PL in the Cu2ZnSnS4 nanocrystals. Electrochemical studies helped to prove that an inorganic-organic heterojunction of nanokesterite-phenoxazine was obtained. Device studies showed a two fold improvement in efficiency upon addition of a kesterite or phenoxazines-kesterite layer.

A simple chemical transport method was used to obtain Ga-core / SiO2-shell microstructures. The cone-shaped silica needles assembled in a highly ordered pattern on a gallium droplet. Morphology of those regularly arranged microstructures was present in scanning electron microscopy images. The chemical composition and structure were confirmed using energy dispersive X-ray and Raman spectroscopy. Such core-shell, gallium-silicon dioxide regular microstructures are reported for the first time.

Ammonium hexachlorostannate single crystals were obtained from gas phase of decomposition products of SnCl4·5NH3 formed in reaction of liquid tin(IV) chloride with gaseous ammonia. The crystals of both cubic (NH4)2SnCl6, obtained hitherto only by crystallization from solution, and of the formerly unknown orthorhombic polymorph were deposited on inner walls of the quartz reactor used. The values of the structure refinement factor R obtained is 0.01. Unit cell parameters of the new orthorhombic form of ammonium hexachlorostannate were determined and are reported.

A rapid development of solar cells has been observed within recent years. Semiconducting materials based on Cu2ZnSnS4 with the kesterite structure offer a promise of low-cost and environmentally friendly solar cells. The energy gap of Cu2ZnSnS4, which is about 1.5 eV, can be optimized with addition of organic ligands. We report a method of obtaining kesterite nanopowders with grain diameter of approximately 5 nm via solution synthesis using metal chlorides and sulfur in oleylamine at 230 °C. The ligand exchange for diphenylamine upshifted the value of the bandgap to 2.2 eV, which makes it a promising material for an upper layer in tandem photovoltaic devices.

Efficient and inexpensive method of chemical transport based on Ag2S catalyst was used to produce relatively large crystals of SnS2, up to 5 mm in linear size. Good quality of the obtained layered crystals of SnS2 was confirmed by X-ray, SEM, EDX and Raman measurements, however the layers appeared to be slightly twisted in relation to each other. Nanometric (down to c.a. 10 nm) layers of SnS2 on a Si substrate were obtained by mechanical exfoliation.

The formation of a previously unknown salt with the stoichiometry Li5GeNO3 was found during studies on the reactivity of lithium metagermanate with lithium nitride, germanium oxynitride, and LiGeNO and Li3GeNO2 with lithium oxide. The possibility of existence of anion GeNO35− with mixed oxygen-nitrogen coordination shell of germanium had been predicted on the basis of analogies occurring among known silicon and germanium compounds. The course of thermal decomposition of the new salt was determined.

A rapid development of photovoltaics has been observed recently. Permanent interest in new cheap and efficient photovoltaic devices stimulates a constant search for new semiconductor materials and structures. The success of materials based on CIGS (CuIn1–xGaxSe2) is limited by the prohibitive prices of the elements In and Ga. A family of quaternary semiconducting materials of the Cu2ZnSnS4 type, crystallizing mainly in the kesterite structure, offers a promise of new cheap photovoltaic materials. Kesterite is manufactured from nontoxic and naturally abundant materials. The energy gap of Cu2ZnSnS4 is about 1.5 eV, and the absorption coefficient of this direct-band-gap material is α > 104 cm–1 for photon energies higher than the energy gap. In this paper, we report a method of obtaining free-standing single crystals of kesterite (Cu2ZnSnS4).

A growing interest in devices based on spintronics demands a development of magnetic semiconductors. A promising material for such applications is kesterite doped with ferromagnetic elements. We present a method of obtaining Cu2MSnS4 (M = Zn, Fe, Mn, Ni) single crystals, using metals, elemental sulfur and minor amounts of iodine. The syntheses were carried out in quartz ampoules closed under vacuum and heated in a tube furnace at 650 °C for 7 to 90 days. A method of synthesis of comparatively good tetragonal single crystals of Cu2FeSnS4 and Cu2MnSnS4 was achieved. Raman spectra of purely Mn- and Ni-substituted kesterites have been measured for the first time.

The formation of a previously unknown salt with the stoichiometry Li5GeNO3 was found during studies on the reactivity of lithium metagermanate with lithium nitride, germanium oxynitride, and LiGeNO and Li3GeNO2 with lithium oxide. The possibility of existence of anion GeNO35− with mixed oxygen-nitrogen coordination shell of germanium had been predicted on the basis of analogies occurring among known silicon and germanium compounds. The course of thermal decomposition of the new salt was determined.

A growing interest in devices based on spintronics demands a development of magnetic semiconductors. A promising material for such applications is kesterite doped with ferromagnetic elements. We present a method of obtaining Cu2MSnS4 (M = Zn, Fe, Mn, Ni) single crystals, using metals, elemental sulfur and minor amounts of iodine. The syntheses were carried out in quartz ampoules closed under vacuum and heated in a tube furnace at 650 °C for 7 to 90 days. A method of synthesis of comparatively good tetragonal single crystals of Cu2FeSnS4 and Cu2MnSnS4 was achieved. Raman spectra of purely Mn- and Ni-substituted kesterites have been measured for the first time.

Bulk single crystals of Cu2ZnSnS4 of kesterite structure with dimensions up to 1 x 1 x 0.5 mm are prepared from naturally abundant CuS, ZnS, and SnS in a molar ratio of 2:1:1 (evacuated quartz ampule, 700 °C, 24—240 h).