ABSTRACT
The development of semiconducting polymers with good processability in green solvents and competitive electrical performance is essential for realizing sustainable large-scale manufacturing and commercialization of organic electronics. A major obstacle is the processability-performance dichotomy that is dictated by the lack of ideal building blocks with balanced polarity, solubility, electronic structures, and molecular conformation. Herein, through the integration of donor, quinoid and acceptor units, an unprecedented building block, namely TQBT, is introduced for constructing a serial of conjugated polymers. The TQBT, distinct in non-symmetric structure and high dipole moment, imparts enhanced solubility in anisole-a green solvent-to the polymer TQBT-T. Furthermore, PTQBT-T possess a highly rigid and planar backbone owing to the nearly coplanar geometry and quinoidal nature of TQBT, resulting in strong aggregation in solution and localized aggregates in film. Remarkably, PTQBT-T films spuncast from anisole exhibit a hole mobility of 2.30 cm2 V-1 s-1, which is record high for green solvent-processable semiconducting polymers via spin-coating, together with commendable operational and storage stability. The hybrid building block emerges as a pioneering electroactive unit, shedding light on future design strategies in high-performance semiconducting polymers compatible with green processing and marking a significant stride towards ecofriendly organic electronics.
ABSTRACT
Enhancing the solution-processability of conjugated polymers (CPs) without diminishing their thin-film crystallinity is crucial for optimizing charge transport in organic field-effect transistors (OFETs). However, this presents a classic "Goldilocks zone" dilemma, as conventional solubility-tuning methods for CPs typically yield an inverse correlation between solubility and crystallinity. To address this fundamental issue, a straightforward skeletal randomization strategy is implemented to construct a quinoid-donor conjugated polymer, PA4T-Ra, that contains para-azaquinodimethane (p-AQM) and oligothiophenes as repeat units. A systematic study is conducted to contrast its properties against polymer homologues constructed following conventional solubility-tuning strategies. An unusually concurrent improvement of solubility and crystallinity is realized in the random polymer PA4T-Ra, which shows moderate polymer chain aggregation, the highest crystallinity and the least lattice disorder. Consequently, PA4T-Ra-based OFETs, fabricated under ambient air conditions, deliver an excellent hole mobility of 3.11 cm2 V-1 s-1, which is about 30 times higher than that of the other homologues and ranks among the highest for quinoidal CPs. These findings debunk the prevalent assumption that a random polymer backbone sequence results in decreased crystallinity. The considerable advantages of the skeletal randomization strategy illuminate new possibilities for the control of polymer aggregation and future design of high-performance CPs, potentially accelerating the development and commercialization of organic electronics.
ABSTRACT
The meta-analysis was conducted to evaluate the correlations between common genetic polymorphisms in the IFN-γ gene and susceptibility to breast cancer. The following electronic databases were searched without language restrictions: MEDLINE (1966 ~ 2013), the Cochrane Library Database (issue 12, 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), Web of Science (1945 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). Meta-analysis was performed with the use of the STATA statistical software. Odds ratios (OR) with their 95 % confidence intervals (95 % CIs) were calculated. Nine clinical case-control studies met all the inclusion criteria and were included in this meta-analysis. A total of 1,182 breast cancer patients and 1,525 healthy controls were involved in this meta-analysis. Three functional polymorphisms were assessed, including rs2069705 C>T, rs2430561 T>A, and CA repeats 2/X. Our meta-analysis results indicated that IFN-γ genetic polymorphisms might be significantly associated with an increased risk of breast cancer (allele model: OR = 1.37, 95 % CI = 1.03 ~ 1.83, P = 0.031; dominant model: OR = 1.55, 95 % CI = 1.01 ~ 2.37, P = 0.046; homozygous model: OR = 2.23, 95 % CI = 1.30 ~ 3.82, P = 0.004; respectively), especially the rs2430561 T>A polymorphism. Subgroup analysis based on ethnicity suggested that genetic polymorphisms in the IFN-γ gene were closely correlated with increased breast cancer risk among Asians (allele model: OR = 1.21, 95 % CI = 1.02 ~ 1.58, P = 0.017; dominant model: OR = 3.44, 95 % CI = 2.07 ~ 5.71, P < 0.001; recessive model: OR = 1.58, 95 % CI = 1.06 ~ 2.37, P = 0.025; homozygous model: OR = 1.83, 95 % CI = 1.19 ~ 2.80, P = 0.006; respectively), but not among Caucasians (all P > 0.05). Our meta-analysis supported the hypothesis that IFN-γ genetic polymorphisms may contribute to an increased risk of breast cancer, especially the rs2430561 T>A polymorphism among Asians.
