Water-soluble Cu+- and Ag+-doped ZnxCd1−xS quantum dots have been successfully synthesized via a facile and green method. All synthetic procedures were conducted in the open air at 95 °C. Hydrophilic glutathione was used as the capping agent. The influence of the dopant concentration in alloyed ZnxCd1−xS QDs has been investigated. The as-prepared Cu+- and Ag+-doped ZnxCd1−xS/ZnS core–shell quantum dots exhibit tunable emission covering the whole visible light region and the photoluminescence quantum yield (PL QY) can reach as high as 20% and 31%, respectively.

Homogeneous molecular precursor solutions are excellent choices for obtaining smooth absorber layers, and they offer the potential to significantly lower the manufacturing cost of solar cells. Here, we present a thermally degradable metal butyldithiocarbamate-based solution approach to fabricate Cu2ZnSn(S,Se)4 solar cells. Low-cost Cu2O, ZnO, and SnO were used as the starting materials and were dissolved in the ethanol solution of butyldithiocarbamic acid. By tuning the composition of the Cu2ZnSn(S,Se)4 thin film, a power conversion efficiency of 6.03% on the basis of the active area has been achieved.Keywords: CZTSSe; kesterite; solar cells; solution process; thin film;

Water-soluble Cu–In–S/ZnS core/shell quantum dots with a photoluminescence quantum yield up to 38% and an emission peak tunable from 543 to 625 nm have been successfully synthesized. All of the synthetic procedures were conducted in an aqueous solution at 95 °C under open-air conditions. l-Glutathione and sodium citrate were used as the dual stabilizing agents to balance the reactivity between copper and indium ions.

Metastable wurtzite I3-III-IV-VI5 (Cu3InSnS5) semiconductor nanocrystals were successfully synthesized via a hot-injection approach. The structure, composition, morphology, and optical properties of Cu3InSnS5 were characterized by powder X-ray diffraction, energy dispersive spectrometry, transmission electron microscopy, and UV–Vis absorption. Their suitable band gap value and photoresponse indicate a high potential application in the field of thin film solar cells.

A novel and versatile metal–organic molecular precursor-based solution approach and the fabrication of high efficiency Cu(In,Ga)(S,Se)2 solar cells are presented. Many types of metal oxides, hydroxides, and acetylacetonates (acac), such as Cu2O, ZnO, SnO, Sb2O3, MnO, PbO, In(OH)3, Cd(OH)2, Ga(acac)3, and so forth, can be easily dissolved in butyldithiocarbamic acid, forming thermally degradable metal–organic molecular precursor solutions. By developing a simple and green ethanol solution-processed route and tuning the chemical composition of the Cu(In,Ga)(S,Se)2 thin film, as-fabricated solar cells exhibit an average power conversion efficiency up to 8.8%.Keywords: chalcopyrite; CIGS; molecular precursor; solar cells; solution process;

Quaternary semiconductor Cu2MSnS4 (M = Co2+, Fe2+, Ni2+, Mn2+) nanocrystals have been successfully synthesized via a simple and mild solvothermal method. Cu2FeSnS4 and Cu2CoSnS4 show a spherical shape; Cu2NiSnS4 and Cu2MnSnS4 possess a nail-like structure and a rod-like structure. The four types of nanocrystals exhibit significantly different magnetic properties. Cu2FeSnS4 and Cu2CoSnS4 nanoparticles show ferromagnetic behavior; Cu2MnSnS4 and Cu2NiSnS4 nanorods exhibit superparamagnetic behavior at low temperature. The band gaps of Cu2MSnS4 (M = Co, Fe, Ni, Mn) nanocrystals are in the range of 1.2–1.5 eV, indicating a high potential application in low-cost thin film solar cells.

A series of (ZnS)x(CuInS2)1−x hierarchical micro/nano-structured solid solutions with precisely controlled chemical composition were synthesized via a facile one-pot solvothermal method. ZnO, Cu2O, and In(OH)3 are used as the starting materials and dissolved in ethanol dithiocarbamic acid which is formed from CS2 and ethanolamine in situ. The ethanol dithiocarbamic acid not only serves as a thermally-degradable ligand, but also acts as sulfur source during synthesis, and can be completely removed by a simple calcination process. As-prepared (ZnS)x(CuInS2)1−x microspheres have a hierarchical micro/nano structure composed of around 7 nm nanoparticles. These samples show excellent photocatalytic H2 evolution activity under visible-light irradiation without any noble metal loading owing to their high surface area (as high as 101.6 m2 g−1) and unique hierarchical structure.

Novel semiconductor Cu2CdSnS4 nanorods with a wurtzite structure have been successfully synthesized and characterized in detail. The suitable band gap of 1.4 eV and photoresponse property of Cu2CdSnS4 nanorods indicate that they have a high potential application in low-cost thin film solar cells.

TiO2/(ZnS)x(CuInS2)1−x nanocomposites were prepared from oleic acid-capped TiO2 nanocrystals and alloyed (ZnS)x(CuInS2)1−x nanocrystals. Element mapping and transmission electron microscopy (TEM) results suggested that the nanocomposites exhibit homogeneous composition with uniform mesoporous structure. High photocatalytic activities driven by simulated solar light were achieved owning to their high surface area and efficient electron transfer from (ZnS)x(CuInS2)1−x to TiO2. This work enables the synthesis of a large variety of photocatalysts from nanocrystal building blocks for various applications beyond photodegradation of organic pollutants.

Dilute magnetic semiconductor Cu2MnSnS4 nanocrystals with a novel zincblende and wurtzite structure have been successfully synthesized and reported for the first time. Cu+, Mn2+, and Sn4+ occupy the same position and have a random distribution in the zincblende and wurtzite unit cells. The nanocrystals exhibit a weak ferromagnetic behavior at low temperature.

Cu2SnS3 nanocrystals with metastable zincblende and wurtzite structures have been successfully synthesized for the first time. Alloyed (ZnS)x(Cu2SnS3)1−x and (CuInS2)x(Cu2SnS3)1−x nanocrystals with arbitrary composition (0 ≤ x ≤ 1) and ultra-broad tunable band gaps (3.63 to 0.94 eV) were obtained.

Metastable zinc blende CuInSe2 nanocrystals were synthesized by a hot-injection approach. It was found that the lattice mismatches between zinc blende CuInSe2 and ZnSe as well as CuInSe2 and CuInS2 are only 2.0% and 4.6%, respectively. Thus, alloyed (ZnSe)x(CuInSe2)1–x and CuInSexS2–x nanocrystals with a zinc blende structure have been successfully synthesized over the entire composition range, and the band gaps of alloys can be tuned in the range from 2.82 to 0.96 eV and 1.43 to 0.98 eV, respectively. These alloyed (ZnSe)x(CuInSe2)1–x and CuInSexS2–x nanocrystals with a broad tunable band gap have a high potential for photovoltaic and photocatalytic applications.

A series of (ZnS)x(CuInS2)1−x hierarchical micro/nano-structured solid solutions with precisely controlled chemical composition were synthesized via a facile one-pot solvothermal method. ZnO, Cu2O, and In(OH)3 are used as the starting materials and dissolved in ethanol dithiocarbamic acid which is formed from CS2 and ethanolamine in situ. The ethanol dithiocarbamic acid not only serves as a thermally-degradable ligand, but also acts as sulfur source during synthesis, and can be completely removed by a simple calcination process. As-prepared (ZnS)x(CuInS2)1−x microspheres have a hierarchical micro/nano structure composed of around 7 nm nanoparticles. These samples show excellent photocatalytic H2 evolution activity under visible-light irradiation without any noble metal loading owing to their high surface area (as high as 101.6 m2 g−1) and unique hierarchical structure.

Water-soluble Cu+- and Ag+-doped ZnxCd1−xS quantum dots have been successfully synthesized via a facile and green method. All synthetic procedures were conducted in the open air at 95 °C. Hydrophilic glutathione was used as the capping agent. The influence of the dopant concentration in alloyed ZnxCd1−xS QDs has been investigated. The as-prepared Cu+- and Ag+-doped ZnxCd1−xS/ZnS core–shell quantum dots exhibit tunable emission covering the whole visible light region and the photoluminescence quantum yield (PL QY) can reach as high as 20% and 31%, respectively.

Quaternary semiconductor Cu2MSnS4 (M = Co2+, Fe2+, Ni2+, Mn2+) nanocrystals have been successfully synthesized via a simple and mild solvothermal method. Cu2FeSnS4 and Cu2CoSnS4 show a spherical shape; Cu2NiSnS4 and Cu2MnSnS4 possess a nail-like structure and a rod-like structure. The four types of nanocrystals exhibit significantly different magnetic properties. Cu2FeSnS4 and Cu2CoSnS4 nanoparticles show ferromagnetic behavior; Cu2MnSnS4 and Cu2NiSnS4 nanorods exhibit superparamagnetic behavior at low temperature. The band gaps of Cu2MSnS4 (M = Co, Fe, Ni, Mn) nanocrystals are in the range of 1.2–1.5 eV, indicating a high potential application in low-cost thin film solar cells.

Novel semiconductor Cu2CdSnS4 nanorods with a wurtzite structure have been successfully synthesized and characterized in detail. The suitable band gap of 1.4 eV and photoresponse property of Cu2CdSnS4 nanorods indicate that they have a high potential application in low-cost thin film solar cells.

TiO2/(ZnS)x(CuInS2)1−x nanocomposites were prepared from oleic acid-capped TiO2 nanocrystals and alloyed (ZnS)x(CuInS2)1−x nanocrystals. Element mapping and transmission electron microscopy (TEM) results suggested that the nanocomposites exhibit homogeneous composition with uniform mesoporous structure. High photocatalytic activities driven by simulated solar light were achieved owning to their high surface area and efficient electron transfer from (ZnS)x(CuInS2)1−x to TiO2. This work enables the synthesis of a large variety of photocatalysts from nanocrystal building blocks for various applications beyond photodegradation of organic pollutants.

Cu2SnS3 nanocrystals with metastable zincblende and wurtzite structures have been successfully synthesized for the first time. Alloyed (ZnS)x(Cu2SnS3)1−x and (CuInS2)x(Cu2SnS3)1−x nanocrystals with arbitrary composition (0 ≤ x ≤ 1) and ultra-broad tunable band gaps (3.63 to 0.94 eV) were obtained.