Response to commentary “Zinc is decreased in prostate cancer: an established relationship of prostate cancer!”

10.1007/s00775-010-0737-8Journal of Biological Inorganic Chemistry1619-13JJBC

Aluminium oxide formation via atomic layer deposition using a polymer brush mediated selective infiltration approach

Area selective deposition (ASD) is an emerging method for the patterning of electronic devices as it can significantly reduce processing steps in the industry. A potential ASD methodology uses infiltration of metal precursors into patterned polymer materials. The work presented within demonstrates this potential by examining hydroxy terminated poly(2-vinylpyridine) (P2VP-OH) as the ‘receiving’ polymer and trimethylaluminium (TMA) and H2O as the material precursors in a conventional atomic layer deposition (ALD) process. Fundamental understanding of the surface process was achieved using X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) mapping via transmission electron microscopy (TEM). The resulting analysis confirms aluminium inclusion within the polymer film. Spectroscopic and microscopic characterisation show metal infiltration throughout the polymer to the underlying silicon dioxide interface. Exposing the infiltrated film to an oxygen plasma results in the removal of the organic component and resultant fabrication of a sub 5 nm aluminium oxide layer.acceptedVersionPeer reviewe

Effect of dielectric barrier on rectification, injection and transport properties of printed organic diodes

acceptedVersionPeer reviewe

Selective atomic layer deposition on flexible polymeric substrates employing a polyimide adhesive as a physical mask

The rise of low-temperature atomic layer deposition (ALD) has made it very attractive to produce high- κ dielectric for flexible electronic devices. Similarly, selective deposition of ALD films is of great relevance for circuitry. We demonstrated a simple method of using a physical mask to block the film's growth in selected polymeric and flexible substrate areas during a low-pressure ALD process. A low-cost silicone adhesive polyimide tape was used to manually mask selected areas of bare substrates and aluminum strips deposited by evaporation. 190 cycles of aluminum oxide (Al 2O 3) and hafnium oxide (HfO 2) were deposited at temperatures ranging from 100 to 250 °C. Using x-ray photoelectron spectroscopy (XPS) analysis and energy dispersive x-ray spectroscopy (EDS), we showed that the mask was effective in protecting the areas under the tape. The mask did not show any modification of shape for an exposure of 10 h at 250 °C, hence keeping the form of the masked area intact. An analysis of the unmasked area by ellipsometry (632.8 nm) and x ray shows a regular film with a thickness variation under 2 nm for a given temperature and constant refractive index. EDS, selected-area XPS, and imaging XPS show an evident change of elemental content at the interface of two areas. By XPS, we established that the structure of the films was not affected by the mask, the films were stoichiometric, and there was no effect of outgassing from the adhesive film.publishedVersionPeer reviewe

Less Is More: Simplified Fluorene-Based Dopant-Free Hole Transport Materials Promote the Long-Term Ambient Stability of Perovskite Solar Cells

The stability of perovskite solar cells (PSCs) is greatly affected by the interface between the perovskite active layer and the hole transport material (HTM). The rational design of HTMs with effective anchoring to the perovskite surface is an emerging elegant strategy to promote compact and ordered interfaces that lead to highly efficient and stable PSCs. Herein, we propose two fluorene-based HTM molecular architectures (SCF1 and SCF2) derived from the popular yet expensive Spiro-OMeTAD. Their employment as dopant-free HTMs in standard triple-cation CsFAMA PSCs leads to superior device stability, with a T80 lifetime well above 1 year (431 days). Our combined theoretical and experimental study of the CsFAMA|HTM interface reveals that the improved adhesion of the SCF-HTMs to the perovskite layer is the key to minimize the non-radiative recombination, reduce the hole trap density, and enhance the long-term stability of the corresponding devices. The simplified structures of SCF1 and SCF2, obtained by removing the orthogonal fragment of the Spiro-OMeTAD scaffold, show a lower molecular distortion than Spiro-OMeTAD, thus promoting a favorable electronic interaction between the SCF-HTMs and the perovskite. This study provides useful design criteria for achieving highly stable PSCs including dopant-free HTMs with optimized adhesion to the perovskite surface

Visible to near-infrared broadband fluorescence from Ce-doped silica fiber

Abstract We investigate the fluorescence characteristics of a purely Ce-doped silica fiber and demonstrate broad-bandwidth fluorescence across the visible and near-infrared. The Ce-doped fiber is fabricated using standard modified chemical vapor deposition technology. Trace metal analysis by inductively coupled plasma mass spectrometry confirmed the purity of Ce-doping. The Ce valence state of 3+ was revealed by X-ray photoelectron spectroscopy. The optimum pump wavelength for the broadest luminescence from a fiber is scanned between 405 nm to 440 nm wavelength of diode lasers operating under continuous-wave regime. The strongest pump absorption is observed at the wavelength of 405 nm. Variation of pump power and fiber length results in the demonstration of broad-bandwidth fluorescence with spectral widths up to 301 nm (at -10 dB). The measured fluorescence spectra cover the wavelength range from ∼458 nm to ∼819 nm with spectral power densities of up to 2.4 nW/nm