Falah I. Mustafa

A highly sensitive flexible SnS thin film photodetector in the ultraviolet to near infrared prepared by chemical bath deposition

This study involves a novel fabrication of a high performance, low cost and flexible (SnS nanoflake based) photodetector on a polyethylene terephthalate (PET) substrate by using chemical bath deposition. The photoresponse properties of the fabricated SnS nanostructure in the ultraviolet (UV) to near infrared (NIR) region were studied. The photodetector was subjected to illumination from four light emitting diodes (LEDs) characterized by spectra peaks of 380, 530, 750 and 850 nm, respectively. The photodetector exhibited a good photoresponse, fast response and high reproducibility with time. The sensitivity values of the photodetector were determined to be approximately 2990, 1604, 2591, and 446 for wavelengths of 380, 530, 750, and 850 nm at a bias voltage of 3 V. At the bias voltage of 5 V, the sensitivity values of 2575, 1262, 1635 and 295 were recorded for 380, 530, 750 and 850 nm respectively. The photodetector also manifests fast photoresponse for the illumination wavelengths. Based on the abovementioned results, in addition to its low cost, flexibility, and non-toxic nature, the SnS photodetector is a promising photoelectronic device that is effectively applicable over the UV-vis-NIR range.

Dust effects on the performance of PV street light in Baghdad city

This paper deals with the study of the dust characteristics and its effect on the performance of street photovoltaic cells in Baghdad-Iraq. Sample of accumulated dust on the surface of the solar panels at height 26 meters have been microscopy examined with 100x magnification. The results show that, varies in size, shape and disruption. The morphology of dust particles has irregular forms, tends to be spherical and not all of them are completely opaque. VOC (group of carbon-based chemicals that easily evaporate at room temperature), which is most of them comes from the refineries causes a large adhesion to the dust particles in the installed solar panel.

Self cleaning control system for PV solar panel street light

This work present a design, build a wet and dry self cleaning system to the street light solar panel. It is simple, lightweight, slight to maintain, portable, withstand the environment; low-cost, long life, takes its power from the battery of the solar panel, and controlled automatically, by a remote control or a timer. The experimental model is based on a DC motor intelligently controls by a dedicated drive unit that move a cleaning head on the panel upwards and downwards with without using, spraying system. The performance and characteristics of the self cleaning system is experimentally analyzed.

Selenium metal flexible solar cell

Se, InSe, GaSe/CdS three solar cells pn junction thin films are deposited at room temperature on ITO glass and PET polymer flexible substrates by thermal evaporation technique at high vacuum pressure 2×10-5 mbar. The X-Ray diffraction analysis showed that all are amorphous in nature while the as-deposited film CdS is polycrystalline. The optical energy gap and carrier concentration of Se, InSe, GaSe and CdS thin films are found 1.95eV, 1.6eV, 2.46eV and 2.4eV respectively with p=8.4×109cm-3, p=6.7×1011cm-3, p=1.2×109cm-3 and n=3.1×1013cm-3 respectively. The four layers structure of solar cell formed by deposited CdS film with variable thickness t=200,300,550 nm on ITO conductive polyester film PET; R=15 (ohms per sq) with t=175 um or ITO deposited on glass 1mm thickness with deposited layers of Se, InSe and GaSe thin films in variable thickness t=700nm and 1000nm then Aluminum electrode as back surface. The results showed the efficiency decrease with increase thickness of thin films of semiconductors for CdS/InSe solar cell from %0.506 to %0.055 respectively, while we found efficiency solar cells increase when used ITO on Glass rather than ITO on PET substrate for pn junctions CdS/Se, CdS/InSe and CdS/GaSe from %0.377 to %0.355, %0.506 to %0.123 and %0.073 to %0.061 respectively.

Direct and indirect sensing two-axis solar tracking system

The main goal of this project is to design a very precise solar tracker. The project is divided into two parts; hardware and software. Hardware part generally composed of solar panel, two-DC motors with gearbox, LDR sensor module and electronic circuit. Software part represents the thinking behavior of the system, that is how the system acting under several weather conditions. In this work sensing of the sun position carried out in two stages primary and secondary. Primary stage or indirect sensing performed via sun-earth relationship as a coarse adjustment and second stage or direct sensing performed via set of LDR sensors as output tuning to trims the azimuth and altitude angles. If the weather is cloudy or dusty, the tracking system uses primary stage or sun-earth geometrical relationships only to identify the location of the sun; so the system tracks the position of the sun regardless the weather condition. The energy extracted from photovoltaic (PV) or any solar collector depends on solar irradiance. For maximum extraction of energy from the sun, the solar collector panel should always be normal to the incident radiation Solar trackers moves the solar collector to follow the sun path and keeps the orientation of the solar collector at an optimal tilt angle. Solar tracking system improves substantially the energy efficiency of photovoltaic (PV) panel. In this paper, an automatic dual axis solar tracking system is designed and developed using Light Dependent Resistor (LDR) and DC motors on a mechanical structure with gear arrangement. Two-axis solar tracking (azimuth angle as well as altitude angle) is implemented through Arduino UNO controller based on Sun-Earth Geometry. The results indicated that the automatic solar tracking system is more reliable and efficient than fixed one.

InSe Nanothin Film with Ar-Gas Low Vacuum Pressure

InxSe1-x (x = 0.4, 0.5, 0.6) thin films are deposited at room temperature on glass substrates with thickness ~500nm by thermal evaporation technique. The X-Ray diffraction analysis showed that both the as-deposited films In2Se3 and InSe (x= 0.4 and 0.5) are amorphous in nature while the as-deposited film In3Se2 is polycrystalline and the values of energy gap are Eg=1.44eV for In2Se3, Eg=1.16eV for InSe and Eg=0.78eV for In3Se2. The same technique used with insert Argon gas at pressure 0.1 mbar where InxSe1-x (x = 0.4, 0.5, 0.6) thin films are deposited at room temperature on glass substrates with thickness ~100nm. The X-Ray diffraction analysis showed that the as-deposited films In2Se3 are amorphous in nature while the as-deposited film InSe and In3Se2 are Nanocrystalline with grain size 33nm and 55nm respectively and the values of energy gap are Eg=1.55eV for InSe and Eg=1.28eV for In3Se2. The energy gap of InSe thin films increase with Argon gas assist and phases changes from amorphous and polycrystalline to nanostructure material by thermal vacuum deposition technique.