Papers by Keyword: Visible Region

Abstract: Multiwall carbon nanotubes (MWCNTs) have recently attracted much attention due to their appealing properties in several domains. Multiwall carbon nanotubes (MWCNTs) were functionalized in this research study and then decorated with silver nanoparticles. Fourier transform Infrared Spectroscopy (FTIR) was used to check the successful attachment of hydroxyl (OH) and carboxyl (C=O) groups with MWCNTs. XRD analysis was used to check the crystallite size of silver nanoparticles and the decoration of silver nanoparticles on MWCNTs. Pure Carbon nanotubes (CNTs) show luminescence in an infrared region having approximately 1.3 eV absorption band. At room temperature, our hybrid material's photoluminescence (PL) spectra indicate only one peak in the UV region and many high-intensity peaks in the visible region. These PL results show the change in the band structure of Ag/MWCNTs composite compared to pure silver nanoparticles and carbon nanotubes. Therefore, it unlocks the possibilities to use this hybrid material for bio-sensing and bio-imaging devices, chemical sensing devices, optoelectronics devices, drug delivery devices, cancer cell detection, and environment detection devices.

Abstract: Using polyhedral oligomeric silsesquioxanes (POSS) derived from the hydrolytic condensation of (3–methacryloxypropyl)trimethoxysilane (MPMS), vinyltrimethoxysilane (VMS), and (3-glycidoxypropyl)trimethoxysilane (GPMS), three hybrid nanofilms, f-MP (film-MPMS-POSS), f-GP and f-VP, were prepared using sol-gel and crosslinking processes. The average transparency (AT) and absorption coefficents (AC) of the films were measured in the ranges of 280-2500 nm. Two film transparency applications are described in this work: 1) The AT values of the POSS films in the range of the ultraviolet B (UV-B) spectrum (280–320 nm) (a skin cancer-causing agent) and 2) the AT values in the visible light (VIS) region (400-750 nm) and the near infrared (NIR) region (750-2500 nm) (providing crops growth energy and the improvement of the photosynthetic process efficiency). The AT values of the POSS films in the UV-B range are only about 13%, indicating these films can provide a physical barrier to block UV-B absorption by the skin, and therefore are possible POSS materials for sunscreen ingredients. The AT values in the VIS region are 95.13%, 89.16% and 91.60%, respectively, and the AT values in the near infrared (NIR) region (750-2500 nm) are 95.39%, 93.11% and 90.50%, respectively. These high AT films are good candidates for greenhouse covers. The AT values among the three films in the 280-2500nm region are different and exhibit varied selectivity for absorbed spectra due to the dissimilar sizes of organic branches covalently bonded to the silica network in the film structure.