A ZnPc(COOH) 4 /Fe 3 O 4 /Ch photosensitizer was synthesized by immobilization of ZnPc(COOH) 4 onto Fe 3 O 4 /chitosan nanoparticles by a simple immersion method.
In this study, we report the synthesis and characterization of Fe3O4 nanoparticles coated with dextran. The structural and optical properties of the Dx:Fe3O4 synthesized composites were investigated by Fourier Transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and UV–Vis absorption spectroscopy. For the first time in this paper, the photophysics of Dx:Fe3O4 composites in water is studied using fluorescence and phosphorescence molecular spectrometry. An analysis of the absorption spectra of the Dx:Fe3O4 composite reveals the broad absorption bands with maxima at wavelengths of 227 nm, 264 nm, and 340 nm. Dx:Fe3O4 composite nanoparticles in water exhibit strong fluorescence with a quantum yield of 0.24% in contrast to 0.07% for dextran. Phosphorescence spectra confirm the formation of new emission bands within the Dx:Fe3O4 solution evidenced by the maxima shift for both dextran and Dx:Fe3O4 composites.
This paper focuses on physical properties of ZnSe thin films and photovoltaic parameters of ZnSe/CdTe thin film solar cells. X-ray analysis and SEM images show that ZnSe films are polycrystalline and exhibit wurtzite-zinc-blende structure. ZnSe/CdTe solar cells show an efficiency of about 4.7%. The external quantum efficiency (EQE) for these cells shows that the shape of these characteristics depends on ZnSe layer thickness. The incorporation of Zn at the ZnSe and CdTe interface, for the first time, doubles the short circuit current density and improves the performance of ZnSe/CdTe thin film solar cells.
In this study, zinc phthalocyanine (ZnPc) and copper phthalocyanine (CuPc) thin films fabricated by drop casting (DC) and close space sublimation (CSS) have been investigated and compared with ZnPc and CuPc solutions in formic acid (29 µmol/L). The results show that the CSS method produces films with improved molecular ordering, enhanced surface uniformity, superior optical and morphological properties compared to those obtained by drop casting. Moreover, CSS allows a precise and reproducible deposition, resulting in thinner, homogeneous layers with strong substrate adhesion and fewer defects. Optical characterization confirms that CSS films display high transparency (~90%), a sharp Q-band around 680 nm, and a fluorescence maximum at ~825 nm with the strongest emission intensity.In contrast, DC films show lower transparency (<70%), a slightly shifted Q-band (~675 nm), and similar emission around 825 nm. The fluorescence is strongly thickness-dependent: at ~100 nm, the emission band appears at 795 nm, while films thicker than 300 nm exhibit a red-shifted maximum at ~825 nm. AFM analysis further demonstrates the influence of deposition method: CSS yields smoother films with tunable morphology, while DC produces rougher, less controllable surfaces. Overall, CSS is shown to be the more effective approach for fabricating high-quality phthalocyanine films for optoelectronic applications such as photovoltaics and sensors.