In emerging optoelectronic applications, such as water photolysis, exciton fission and novel photovoltaics involving low-dimensional nanomaterials, hot-carrier relaxation and extraction mechanisms play an indispensable and intriguing role in their photo-electron conversion processes. Two-dimensional transition metal dichalcogenides have attracted much attention in above fields recently; however, insight into the relaxation mechanism of hot electron-hole pairs in the band nesting region denoted as C-excitons, remains elusive. Using MoS2 monolayers as a model two-dimensional transition metal dichalcogenide system, here we report a slower hot-carrier cooling for C-excitons, in comparison with band-edge excitons. We deduce that this effect arises from the favourable band alignment and transient excited-state Coulomb environment, rather than solely on quantum confinement in two-dimension systems. We identify the screening-sensitive bandgap renormalization for MoS2 monolayer/graphene heterostructures, and confirm the initial hot-carrier extraction for the C-exciton state with an unprecedented efficiency of 80%, accompanied by a twofold reduction in the exciton binding energy.

The properties of graphene can vary as a function of the number of layers (NOL). Controlling the NOL in large area graphene is still challenging. In this work, we demonstrate a picosecond (ps) laser thinning removal of graphene layers from multi-layered graphene to obtain desired NOL when appropriate pulse threshold energy is adopted. The thinning process is conducted in atmosphere without any coating and it is applicable for graphene films on arbitrary substrates. This method provides many advantages such as one-step process, non-contact operation, substrate and environment-friendly, and patternable, which will enable its potential applications in the manufacturing of graphene-based electronic devices.

Background:Glypican-3 (GPC3) has been widely recognized in the progression of liver tumors for several years. The relationship between overexpression of GPC3 and the poorer prognosis of patients with hepatocellular carcinoma (HCC) was performed by 2 meta-analyses. However, there were also some latest literatures that indicated different conclusions distinctly. It is necessary for us to carry out a meta-analysis by adding the latest data from current studies to explore the correlation between GPC3 and prognostic value in HCC.Methods:We conducted a meta-analysis including a total of 14 studies to assess the potential prognostic significance of GPC3 expression for overall survival (OS) and disease-free survival (DFS). The expression of GPC3 was assessed by immunohistochemistry.Results:Fourteen studies with 2364 patients were incorporated in the meta-analysis. The combined hazard ratios (HRs) revealed that the overexpression of GPC3 could forecast a poor OS [n = 2233 in 12 studies, HR = 1.40, 95% confidence interval (95% CI): 1.07–1.85, Z = 2.42, P = .02] and DFS (n = 1308 in 10 studies, HR = 1.61, 95% CI: 1.13–2.30, Z = 2.63, P = .008) in HCC patients. Subgroup treated by hepatectomy indicated that the pooled HR of OS was 1.43 (95% CI: 1.01–2.01, P = .04) and the combined HR of DFS was 1.59 (95% CI: 1.09–2.31, P = .02). The pooled odds ratios (ORs) showed that high GPC3 expression was also extensively associated with worse tumor differentiation, later tumor stage, presence of vascular invasion, and hepatitis B virus (HBV) infection. Subgroup analyses for GPC3 on HCC OS based on the studies categorized by regions, follow-up period, and sample size were also conducted.Conclusion:The meta-analysis indicated that overexpression of GPC3 was significantly associated with poor prognosis in patients with HCC.

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