Thermodynamic properties of an interacting hard-sphere Bose gas in a trap using the static fluctuation approximation

A hard-sphere (HS) Bose gas in a trap is investigated at finite temperatures in the weakly-interacting regime and its thermodynamic properties are evaluated using the static fluctuation approximation (SFA). The energies are calculated with a second-quantized many-body Hamiltonian and a harmonic oscillator wave function. The specific heat capacity, internal energy, pressure, entropy and the Bose-Einstein (BE) occupation number of the system are determined as functions of temperature and for various values of interaction strength and number of particles. It is found that the number of particles plays a more profound role in the determination of the thermodynamic properties of the system than the HS diameter characterizing the interaction, that the critical temperature drops with the increase of the repulsion between the bosons, and that the fluctuations in the energy are much smaller than the energy itself in the weakly-interacting regime.Comment: 34 pages, 24 Figures. To appear in the International Journal of Modern Physics

Zinc-bis-8-hydroxyquinoline doped by biochar extracted from red sea algae Chlorophyta as a novel photoactive layer in heterojunction solar cells

Recently, scientists have shown interest in utilizing biochar made from natural sources to enhance various photovoltaic technologies. In this study, Zinc-Bis-8-hydroxyquinoline (Zn-Hq2) was mixed with 10 % biochar obtained from red sea microalgae (Chlorophyta) using a microwave combustion process. This mixture was then used as a novel photoactive layer in a solar cell. The structural properties of Zn-Hq2@BC were analyzed by XRD, FTIR, HRTEM, and SEM. The analysis showed that Zn-Hq2@BC had evenly distributed nano-rods within the BC nanopores network, with widths ranging from 26.94 to 30.90 nm and lengths ranging from 136.43 to 192.38 nm. When measuring dark current density-voltage, it was found that Zn-Hq2@BC/n-Si showed better-rectifying characteristics compared to pristine Zn-Hq2/n-Si, with a higher rectification ratio. The results also showed that the current density and voltage at the maximum power point increased to 5.63 mA/cm2 and 0.45 V, respectively, due to the activation of the biochar. When exposed to light, the addition of approximately 10 % biochar resulted in a 15 % increase in fill factor and a 92 % increase in power conversion efficiency. This is because biochar helps introduce extra charge carriers into the material, thus improving charge transport and reducing recombination losses. These findings reveal the positive effects of microalgae-derived biochar and indicate potential applications of Zn-Hq2 in solar cells