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Hybrid solar cells have been fabricated from solution processing of poly-(3-hexylthiophen-2,5-diyl) onto planar poly-crystalline thin film silicon (poly-Si) absorbers on glass. The poly-Si layers were prepared by laser crystallization. Methyl passivation of the poly-Si surface by a one-step grafting process via methyl-Grignard enabled open circuit voltages of up to 552 mV and an overall power conversion efficiency of 6.6% for this device type. The solar cell exhibited significant advantages compared to the wafer-based counterparts. The inverted device structure of the thin film cell lead to an enhancement of the quantum efficiency since the back side contacted cell had less light absorption and reflection losses due to the gold layer which was used as front contact for the c-Si-based hybrid solar cell. As a result, a photo current of 24.3 mA cm−2 was obtained for a 10 μm thin poly-Si layer on glass. Furthermore, the inverted device structure showed a pronounced increase in stability due to the much thicker gold back contact that reduces the diffusion of water and oxygen toward the polymer layer. After 3 months in ambient air, this type of solar cell operated with 86% of its initial efficiency. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a promising material for the fabrication of optoelectronic devices. In the amorphous state physical-vapor-deposited SiC is already an essential part of the production of electron beam liquid phase crystallized silicon absorbers, because of its good wettability for the silicon melt. The resulting polycrystalline thin film absorbers exhibit excellent electrical properties (B. Eggleston et al. MRS Online Proc. Libr. 1426, 251 (2012)) and demonstrate the potential of this technology (J. Dore et al. IEEE J. Photovolt. 4, 33 (2014)). A drawback of amorphous SiC interlayers is their poor optical properties. In this work we investigate two different approaches. Firstly, we show how those properties can be improved by depositing SiC xO y layers to enhance the transmittance while maintaining the wettability. Secondly, the laser crystallization of amorphous silicon-carbon compounds is studied as a function of their composition and the applied laser fluence. Compared to the amorphous SiC layers a clear reduction of the absorption coefficient was achieved upon laser annealing without losing wettability. Raman backscattering measurements showed that laser annealing of reactively sputtered amorphous SiC leads to a material with a vibrational mode at 770 cm−1 that is indicative of 6H-SiC. Atomic force microscopy measurements of those crystalline layers also show an ordered triangular grain structure, which was not observed in the amorphous material. It is shown that segregation effects are strongly affected by the stoichiometry and the applied laser fluence. [ABSTRACT FROM AUTHOR]

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Background:The detection of V600E BRAF mutations has fundamental clinical consequences as the treatment option with BRAF inhibitors such as vemurafenib or dabrafenib yields response rates of ∼48%. Heterogeneity with respect to BRAF mutation in different metastases has been described in single cases. As this has important implications for the determination of BRAF status and treatment of patients, it is essential to acquire more data.Methods:A total of 300 tumour samples from 187 melanoma patients were analysed for BRAF mutations by pyrosequencing. Equivocal results were confirmed by capillary sequencing. Clinical data with respect to melanoma type, tumour site and survival were summarised for 53 patients with multiple analysed tumour samples (2-13 per patient).Results:BRAF mutations were found in 84 patients (44.9%) and 144 tumour samples (48%) with BRAF mutations in 45.5% of primary tumours and 51.3% of metastases, respectively. In 10 out of 53 patients (18.9%) where multiple samples were analysed results were discordant with respect to mutation findings with wild-type and mutated tumours in the same patient. Mutations did not appear more frequently over the course of disease nor was its occurrence associated with a specific localisation of metastases.Conclusion:As heterogeneity with respect to BRAF mutation status is detected in melanoma patients, subsequent testing of initially wild-type patients can yield different results and thus make BRAF inhibitor therapy accessible. The role of heterogeneity in testing and for clinical response to therapy with a BRAF inhibitor needs to be further investigated. [ABSTRACT FROM AUTHOR]

Background:The detection of V600E BRAF mutation in melanoma is fundamental since here BRAF inhibitors represent an effective treatment. Non-V600E BRAF mutations that may also respond are not detected by certain screening methods. Thus, knowledge about detection of these mutations is needed.Methods:A total of 276 tumour samples from 174 melanoma patients were investigated for BRAF mutations by pyrosequencing. Rare mutations were confirmed by capillary sequencing and compared with findings from COBAS test and immunohistochemistry using a novel BRAF antibody. Melanoma type, localisation, and survival were summarised.Results:BRAF mutations were found in 43% of patients (124 tumours in 75 patients). Among those, 14 patients (18.7%) exhibited rare mutations. The V600EK601del and V600DK601del mutations have never been described before in melanoma. Furthermore, V600K, V600E2, and V600D, V600G, V600R, and L597S mutations were detected. Mutations were not detected by COBAS test in 7 out of these 14 patients and immunohistochemistry only reliably detected patients with the V600E2 and V600EK601del mutation.Conclusion:Accurate diagnosis of rare BRAF mutations is crucial. We show that pyrosequencing is accurate, highly sensitive, reliable, and time saving to detect rare BRAF mutations. Missing these rare variant mutations would exclude a subset of patients from available effective BRAF-targeting therapy. [ABSTRACT FROM AUTHOR]