The photocurrent of a CuIn0.7Ga0.3S2 nano-photocathode increases about 2–3 times after selective etching of a metastable CuAu ordering phase.

Earth-abundant Cu2ZnSnS4 (CZTS) is a promising material for thin film solar cells or solar water splitting cells. Generally, large grain size and vertical penetration are highly desirable microstructures to high-efficiency solar conversion devices. Up to date, some kinds of vacuum methods have been used to prepare large grain-sized CZTS, which are expensive and limit their applications on a large scale. It is still a key challenge to prepare large-grained and vertical-penetration CZTS by a low-cost solution method. In this study, we obtained vertical-penetration CZTS thin film with 1.3 μm grain sizes by a faclie solution method. Different from previous studies, precursor solution was aged in high-humidity air before it was used to prepare CZTS films. The grain size prepared with aging precursor solution was one of the largest among the samples prepared by a solution method after sulfurizing. Moreover, the large-grained CZTS films were used as photocathodes for solar water splitting, which exhibited a much higher photocurrent than those of the samples without aging. To the best of our knowledge, this is the first demonstration to promote grain growth in CZTS by aging precursor solution in high-humidity air. This aging method can offer a reference to prepare other high-performance films.

Manihot esculenta (M. esculenta) is the most important root crop in the world, which has high potential carbohydrate production and adaptability to diverse environments. In this study, we assembled the complete mitochondrial (mt) DNA sequence of M. esculenta into a circular genome of length 682,840 bp, comprising of 32 protein-coding genes, 17 tRNA genes, and three rRNA genes. A neighbour-joining phylogenetic tree was constructed based on 25 plant species and 23 conserved protein-coding genes, suggesting that M. esculenta is evolutionarily close to the Salicaceae plants (Populus tremula and Salix suchowensis) in the same Malpighiales order. The complete mt genome of M. esculenta will provide more desirable information for better understanding the genomic breeding of cassava.