Investigation of morphology, a.c. electrical and optical properties of nanostructured thin film of polypyrrole–bromoaluminium phthalocyanine

In this research, nanocomposite polypyrrole (PPy) + 30 % bromoaluminium phthalocyanine (BrAlPc) was prepared in our laboratory. Optical absorption and field emission scanning electron microscopy characterized the thin films. The powder of nanocomposite was characterized by X-ray diffraction. The nanocomposite PPy + 30 % BrAlPc thin film deposited on pre-cleaned glass substrate with a thickness of 100 nm, which was deposited in a high vacuum device of electron-beam gun in the pressure of 10^?5 mbar. The capacitance and the dissipation factor were measured in a.c. electrical and in the range of 10²–10⁵ Hz frequency and 303–413 K temperatures. The nanoparticles are spherical in shape with an average size about 25–37 nm. Their UV–Vis spectra of the nanocomposite (PPy + 30 % BrAlPc) is typically described by two strong Q and Soret bands 600–700 and 300–400 nm. The results showed a sharp diffraction peak appeared in 2θ = 8.72 (d = 10.1296 Å) and grian size D = 8.991 nm. The results can be described by the theory of Goswami–Goswami for sandwich devices.     

Nature,strength, and concentration of acid sites of erionite-rich zeolite T determined by ammonia—i.r. spectroscopy

HNaK-containing T zeolites with different proton content were synthesized. Subsequently, the samples were characterized by i.r. spectroscopy and temperature-programmed desorption of ammonia. Besides the direct observation of the acid OH groups, ammonia was used as the probe molecule to determine the nature, strength, and concentration of the acid sites. The nature of the acid sites was identified by the different frequencies for ionically bound ammonia (Brönsted sites) and coordinatively bound ammonia (Lewis sites). The different Brönsted sites were characterized by coupling of ammonia—i.r. spectroscopy with a desorption procedure. The temperature-programmed desorption of ammonia was applied as an opportunity for comparison to obtain exact information about the concentration of the different acid sites observed by ammonia—i.r. spectroscopy.