Morphology Driven by Molecular Structure of Thiazole-Based Polymers for Use in Field-Effect Transistors and Solar Cells.

The effects of the molecular structure of thiazole-based polymers on the active layer morphologies and performances of electronic and photovoltaic devices were studied. Thus, thiazole-based conjugated polymers with a novel thiazole-vinylene-thiazole (TzVTz) structure were designed and synthesized. The TzVTz structure was introduced to extend the π conjugation and coplanarity of the polymer chains. By combining alkylthienyl-substituted benzo[1,2-b:4,5-b']dithiophene (BDT) or dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) electron-donating units and a TzVTz electron-accepting unit, enhanced intermolecular interactions and charge transport were obtained in the novel polymers BDT-TzVTz and DTBDT-TzVTz. With a view to using the polymers in transistor and photovoltaic applications, the molecular self-assembly in and their nanoscale morphologies of the active layers were controlled by thermal annealing to enhance the molecular packing and by introducing a diphenyl ether solvent additive to improve the miscibility between polymer donors and [6,6]phenyl-C71-butyric acid methyl ester (PC71 BM) acceptors, respectively. The morphological characterization of the photoactive layers showed that a higher degree of π-electron delocalization and more favorable molecular packing in DTBDT-TzVTz compared with in BDT-TzVTz leads to distinctly higher performances in transistor and photovoltaic devices. The superior performance of a photovoltaic device incorporating DTBDT-TzVTz was achieved through the superior miscibility of DTBDT-TzVTz with PC71 BM and the improved crystallinity of DTBDT-TzVTz in the nanofibrillar structure.

Transcriptome Analysis Reveals Candidate Genes Associated with Leaf Etiolation of a Cytoplasmic Male Sterility Line in Chinese Cabbage (Brassica Rapa L. ssp. Pekinensis).

Cytoplasmic male sterility (CMS) is universally utilized in cruciferous vegetables. However, the Chinese cabbage hau CMS lines, obtained by interspecific hybridization and multiple backcrosses of the Brassica juncea (B. juncea) CMS line and Chinese cabbage, show obvious leaf etiolation, and the molecular mechanism of etiolation remains elusive. Here, the ultrastructural and phenotypic features of leaves from the Chinese cabbage CMS line 1409A and maintainer line 1409B are analyzed. The results show that chloroplasts of 1409A exhibit abnormal morphology and distribution. Next, RNA-sequencing (RNA-Seq) is used to identify 485 differentially expressed genes (DEGs) between 1409A and 1409B, and 189 up-regulated genes and 296 down-regulated genes are found. Genes that affect chloroplasts development, such as GLK1 and GLK2, and chlorophyll biosynthesis, such as PORB, are included in the down-regulated DEGs. Quantitative real-time PCR (qRT-PCR) analysis validate that the expression levels of these genes are significantly lower in 1409A than in 1409B. Taken together, these results demonstrate that leaf etiolation is markedly affected by chloroplast development and pigment biosynthesis. This study provides an effective foundation for research on the molecular mechanisms of leaf etiolation of the hau CMS line in Chinese cabbage (Brassica rapa L. ssp. pekinensis).