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Carbon dioxide plasma (COP) treatment of a fluorine-doped tin oxide (SnO 2 :F, FTO) front electrode was used for the fabrication of p–i–n hydrogenated amorphous silicon (a-Si:H) solar cells. The oxygen and carbon monoxide radicals in COP play important roles of de-doping and doping effects on the surface of FTO, respectively. Through changing the COP treatment time, the de-doping and doping effects could alter the number of oxygen vacancies for both the bulk and the surface of FTO, resulting in an increase in the work function ( W F ) and a decrease in the Schottky barrier at the p-a-SiC:H/FTO interface. Due to an increase in the W F from 4.16 eV to 4.34 eV after 95 s treatment, the open circuit voltage ( V oc ) of the a-Si:H solar cells increased from 915 mV to 965 mV and the fill factor ( FF ) increased from 67.7% to 74.4%. Although the short-circuit current density ( J sc ) decreased from 11.76 mA/cm 2 to 10.36 mA/cm 2 after 95 s COP treatment due to the weakness of Burstein–Moss (BM) shift and the recombination at FTO surface, the conversion efficiency of the a-Si:H solar cell was enhanced by 12.24% after 45 s COP treatment, accompanied by improving the V oc and FF with almost constant J sc . [ABSTRACT FROM AUTHOR]

Abstract: Since metallic biomaterials used for orthopedic and dental implants possess a paucity of reactive functional groups, bioactivity modification of these materials is challenging. In the present work, the titanium discs and rods were treated with carbon dioxide plasma and then incubated in a modified simulated body fluid 1.5SBF to obtain a hydroxyapatite layer. Surface hydrophilicity of samples, changes of surface chemistry, surface morphologies of samples, and structural analysis of formed hydroxyapatite were investigated by contact angle to water, X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). The results demonstrated that hydrophilicity of titanium surface was improved and hydroxyl groups increased after modification with carbon dioxide plasma treatment. The hydroxyl groups on the surface of titanium were the richest after carbon dioxide plasma treatment under the condition of 20W for less than 30s. The hydroxyapatite formability of titanium surface was enhanced by carbon dioxide plasma pretreatment, which was attributed to the surface chemistry. MC3T3-E1 cell as a model cell was cultured on the Ti, CPT-Ti and CPT/SBF-Ti discs in vitro, and the results of the morphology and differentiation of the cell showed that CPT/SBF-Ti was the highest bioactive. The relative parameters of the new bone around the Ti and CPT/SBF-Ti rods including bone mineral density (BMD), a ratio of bone volume to total volume (BV/TV), trabecular thickness (Tb.Th.) and trabecular number (Tb.N.) were analyzed by a micro-computed tomography (micro-CT) after 4-, 8- and 12-week implantation periods in vivo. The results indicated that the CPT/SBF-Ti was more advantageous for new bone formation. [Copyright &y& Elsevier]