Carrier Dynamics of Efficient Triplet Harvesting in AgBiS2 /Pentacene Singlet Fission Solar Cells.

Singlet fission is a process by which an organic semiconductor is able to generate two triplet excitons from a single photon. If charges from the triplets can be successfully harvested without heavy losses in energy, then this process can enable a single-junction solar cell to surpass the Shockley-Queisser limit. While singlet fission processes are commonly observed in several materials, harvesting the resulting triplets is difficult and has been demonstrated with only a few transport materials. Here, transient absorption spectroscopy is used to investigate singlet fission and carrier transfer processes at the AgBiS2 /pentacene (AgBiS2 /Pc) heterojunction. The successful transfer of triplets from pentacene to AgBiS2 and the transfer of holes from AgBiS2 to pentacene is observed. Further singlet fission in pentacene by modifying the crystallinity of the pentacene layer and have fabricated the first singlet fission AgBiS2 /Pc solar cell is enhanced. Singlet fission devices exhibit higher external quantum efficiency compared with the control devices, and thus demonstrating the significant contribution of charges from the singlet fission process.

Splashing-Assisted Femtosecond Laser-Activated Metal Deposition for Mold- and Mask-Free Fabrication of Robust Microstructured Electrodes for Flexible Pressure Sensors.

Flexible pressure sensors play an indispensable role in flexible electronics. Microstructures on flexible electrodes have been proven to be effective in improving the sensitivity of pressure sensors. However, it remains a challenge to develop such microstructured flexible electrodes in a convenient way. Inspired by splashed particles from laser processing, herein, a method for customizing microstructured flexible electrodes by femtosecond laser-activated metal deposition is proposed. It takes advantage of the catalyzing particles scattered during femtosecond laser ablation and is particularly suitable for moldless, maskless, and low-cost fabrication of microstructured metal layers on polydimethylsiloxane (PDMS). Robust bonding at the PDMS/Cu interface is evidenced by the scotch tape test and the duration test over 10 000 bending cycles. Benefiting from the firm interface, the developed flexible capacitive pressure sensor with microstructured electrodes presents several conspicuous features, including a sensitivity (0.22 kPa-1 ) 73 times higher than the one using flat Cu electrodes, ultralow detection limit (<1 Pa), rapid response/recovery time (4.2/5.3 ms), and excellent stability. Moreover, the proposed method, inheriting the merits of laser direct writing, is capable of fabricating a pressure sensor array in a maskless manner for spatial pressure mapping.

Solution-Processed, Inverted AgBiS2 Nanocrystal Solar Cells.

AgBiS2 nanocrystals are a promising nontoxic alternative to PbS, CsPbI3, and CdS quantum dots for solution-fabricated nanocrystal photovoltaics. In this work, we fabricated the first inverted (p-i-n) structure AgBiS2 nanocrystal solar cells. We selected spray-coated NiO as the hole-transporting material and used PCBM/BCP as the electron-transporting material. Combining transient photocurrent and photovoltage measurements with femtosecond transient absorption spectroscopy, we investigated the charge collection process on metal oxide/AgBiS2 interfaces and demonstrated that the NiO/AgBiS2 NC junction in the p-i-n configuration is more efficient for charge carrier collection. The fabricated p-i-n solar cells exhibited a 4.3% power conversion efficiency (PCE), which was higher than that of conventional n-i-p solar cells fabricated using the same sample. Additionally, inverted devices showed an ultrahigh short-circuit current (JSC) over 20.7 mA cm-2 and 0.38 V open-circuit voltage (VOC), suggesting their potential for further improvements in efficiency and, eventually, for large-scale production.

Twin Defect Derived Growth of Atomically Thin MoS2 Dendrites.

Morphology management for tailoring the properties of monolayer transition-metal dichalcogenides (TMDCs), that is, molybdenum disulfide (MoS2), has attracted great interest for promising applications such as in electrocatalysis and optoelectronics. Nevertheless, little progress has been made in engineering the shape of MoS2. Herein, we introduce a modified chemical vapor deposition method to grow monolayer MoS2 dendrites by pretreating substrates with adhesive tapes. The as-grown MoS2 crystals are featured with hexagonal backbones with fractal shapes and tunable degrees. By characterizing the atomic structure, it is found that these morphologies are mainly initiated from the twin defect derived growth and controlled by the S:Mo vapor ratio. Due to the accumulated sulfur vacancies in the cyclic twin regions, strong enhancement of photoluminescence emission is localized, which determines the shape dependency of optical property. This work not only enriches the understanding of the twin defects derived crystal growth mechanism and extends its applications from nanomaterials to two-dimensional crystals, but also offers a robust and controllable protocol for shape-engineered monolayer TMDCs in electrochemical and optoelectronic applications.

Associations between interleukin-1 polymorphisms and gastric cancers among three ethnicities.

AIM: To investigate the associations between interleukin (IL)-1B and IL-1RN polymorphisms and gastric cancers among the Tibet, Hui and Han ethnicities. METHODS: Genomic DNA was extracted from peripheral blood of 210, 205, and 202 healthy volunteers and from 155, 158, and 197 gastric cancer patients from the Tibet, Hui, and Han populations, respectively. Polymorphisms in IL-1B and IL-1RN were analyzed by denaturing high-performance liquid chromatography. RESULTS: Carriers of the IL-1B-31 CC genotype had an increased risk of intestinal type gastric cancer [odds ratio (OR) = 2.17, P = 0.037] in the Tibet ethnicity. Carriers of the IL-1B 2/L genotype had an increased risk of both intestinal and diffuse types of gastric cancer (OR = 2.08, 2.31, P = 0.007, 0.016, respectively) in the Hui ethnicity. In the Han population, carriers of the IL-1B-31 CC, IL-1B-511CT, TT genotypes had increased risk of intestinal type gastric cancer (OR = 2.51, 2.74, 5.66, P = 0.005, 0.002, 0.000, respectively). CONCLUSION: IL-1B and IL-RN genotypes may differentially contribute to gastric cancer among the Tibet, Hui, and Han ethnicities in the Qinghai area of China.

[Prognostic role of apoptosis-related gene Fas-1377 and -670 polymorphisms in breast cancer].

OBJECTIVE: To investigate the correlations between Fas-1377 and -670 polymorphisms and survival in Chinese women with breast cancer. METHODS: Polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP) was used to detect the polymorphism of Fas gene in 310 breast cancer patients with a long-term follow-up (median 10.5 years, range 0.2 - 16.1 years). Survival curves were analyzed by Kaplan-Meier method. RESULTS: The polymorphism of neither Fas-1377 nor Fas-670 was significantly correlated with the overall survival in this series of 310 cases (P > 0.05). However, among 146 patients without lymph node metastasis, the 5-year overall survival (OS) rate was significantly lower in the patients with Fas-1377 AA genotype than that in the patients with Fas-1377 GA or GG genotype (OS: 66.7% vs. 95.4%, P = 0.03). Among 117 patients with lymph node metastasis, both the Fas-1377 and Fas-670 polymorphisms were not significantly correlated with OS (P = 0.42). CONCLUSION: Among breast cancer patients without lymph node metastasis, patients with Fas-1377 AA genotype may have a worse survival, while patients with Fas-1377 GA or GG genotype may not be so.

[Alteration of early growth response 1 expression in gastroenterological cancers and its biological significance].

OBJECTIVE: To investigate the expression of early growth response 1 (EGR1) in gastroenterological cancers and its significance in the pathogenesis. METHODS: RT-PCR was used to determine the expression of EGR1 in normal gastric mucosa tissues from 20 non-tumor patients, gastroenterological tumor tissues and matched para-cancer tissues normal morphologically. RT-PCR and Western blotting were used to analyze the mRNA and protein expression of EGR1 in 20 cancer cell lines. Immunohistochemistry (IHC) was preformed to measure the expression level of EGR1 protein on tissue microarray including 179 tumors and 159 normal tissues. RESULTS: EGR1 was overexpressed in gastric cancer (GC) and its matched adjacent normal tissue (ANT), but not expressed or expressed at a low level in the normal gastric mucosa from the non-tumor patients, which was consistent with the GC gene expression profiling data. Overexpression of EGR1 was seen in the 20 cancer cell lines at both mRNA and protein levels. IHC showed strong positive staining of EGR1 protein in the cytoplasm of both tumor tissues and matched normal tissues and showed negative or weaker nuclear staining in the normal gastric mucosa tissues from non-tumor patients. Overexpression of EGR1 was detected in 87% (49/56) of the GC tissues and 79% (43/54) of their ANTs; 83% (43/52) of the hepatocellular carcinoma tissues and 79% (32/42) of their ANTs; 78% (41/52) of colorectal cancer tissues and 63% (22/35) of their ANTs; and 79% (15/19) of the squamous cell carcinoma tissues and 78% (14/18) of their ANTs. CONCLUSION: EGR1 may be correlated with the abnormal proliferation of cells at the early stage of malignant transformation.

Identification of matrix metalloproteinase 11 as a predictive tumor marker in serum based on gene expression profiling.

PURPOSE: Prognostic markers discovery is a strategy for early diagnosis and individualization therapy for human cancer. In this study, we focus to integrate different methods to identify specific biomarker and elucidate its clinical significance. EXPERIMENTAL DESIGN: A powerful tool named Digital Gene Expression Display online was applied to isolate differentially expressed genes correlated with gastric cancer. Matrix metalloproteinase 11 (MMP11) was selected and confirmed at both mRNA and protein level in 10 cell lines, 123 cases of tumor tissues, and 305 cases of gastric cancer serum specimen by semiquantitative PCR, immunohistochemistry staining, and ELISA techniques, respectively. RESULTS: Our data showed that overexpression of MMP11 at mRNA and protein level was consistently detected in cell lines and primary tumors compared with matched normal tissues. Importantly, serum MMP11 levels were also significantly elevated in gastric cancer patients compared with those of the control subjects (P < 0.001), and the positive expression was well correlated with metastasis in gastric cancer patients (P = 0.009). Furthermore, we have shown that overexpression of MMP11 was associated with the malignant proliferation of AGS cells. CONCLUSIONS: Combination of gene expression profiling and specific clinical resource is a promising approach to validate gene expression patterns associated with malignant phenotype. As a secreted protein, MMP11 may play an important role in carcinogenesis and has potential implication as a biomarker for the diagnosis and prognosis of human cancers including gastric cancer.