Effect Of Illumination Intensity Research Articles

Effect of illumination intensity on the electrical characteristics of Au//SiO2/n-type Si structures with GO and P3C4MT interface layer

Effect of illumination intensity on the electrical characteristics of Au//SiO2/n-type Si structures with GO and P3C4MT interface layer

Zinc oxide based 3-components semiconductor oxide photodiodes by dynamic spin coating method

In this study, the electrical attributes and exposed solar light impacts on the electrical properties were examined for the Al/p-Si structure having InGaZnO interlayer with different rates of Ga component. The films demonstrated the high transparency in the visible zone within percentages of 84–92%. The prepared films' optical bandgap values were utilized by the aid of optical data, and it is indicated that the bandgap values increased with Ga dopant increases. The electrical characteristics of the produced device and the effect of illumination intensity on these characteristics were investigated by the usage of current-voltage and transient measurements at different intensities of exposed light and the produced devices exhibited photoconducting behavior. In addition, electrical parameters with high importance level such as barrier height and ideality factor were calculated by the help of current-voltage measurements and their values were established at predictable level. The capacitance-voltage and conductance-voltage measurements of the produced device were made, and it was determined that they are depended on voltage and frequency, and also interface conditions and series resistance parameters having very large effects on electrical characteristics were calculated by the help of these measurements. It was determined that the energy band gap of the InGaZnO having different contents of Ga ingredient coincides with the energy levels of the semiconductor and the electrolyte. The analyzed results confirm that the fabricated Al/InGaZnO (with different rates of Ga)/p-Si/Al devices have high sensitivity to illumination applied and could be used in advancing optoelectronic applications, especially as a photodiode.

Stability, reusability, and equivalent circuit of TiO2/treated metakaolinite-based dye-sensitized solar cell: effect of illumination intensity on Voc and Isc values

In this research, treated metakaolinite (TMK) was introduced into the TiO2 photoelectrode to fabricated dye-sensitized solar cells (DSSCs). The photovoltaic cells have four main natural components, i.e., a photosensitizer (carotenoid bixin), photoelectrode (TiO2/kaolinite), electrolyte (glycerine carbonate derivative), and counter-electrode (carbon). Their stability, reusability, and equivalent circuit were studied. The presence of 5% of TMK in anatase TiO2 paste decreased the TiO2 band gap from 3.21 to 3.16 eV. The result showed that the presence of 5% of TMK in TiO2 paste was more favorable to obtain higher energy conversion efficiency. Under a light intensity of 200 W/m2, it produced an energy conversion yield of 0.086%. The combination of the electrolyte and the TMK demonstrated a synergistic effect to improve the electrical properties of the DSSC. The energy storage function worked well until the third day of analysis. The DSSC based on TiO2/TMK photoelectrode exhibited 16 times better stability than pure TiO2-based photoelectrode. The Faraday charge transfer processes showed that the TiO2/TMK photoelectrode is not in direct contact with the carbon counter-electrode.

Effect of illumination intensity on a self-powered UV photodiode based on solution-processed NPD:Alq3 composite system

Effect of illumination intensity on a self-powered UV photodiode based on solution-processed NPD:Alq3 composite system

Effect of illumination intensity on the characteristics of Co/Congo Red/p-Si/Al hybrid photodiode

In this study, Congo Red (CR) organic dye interlayer was covered by sping coating on p-Si semiconductor wafer and Co/CR/p-Si/Al photodiode was fabricated. The surface morphology of CR film was characterized by SEM measurement. Current–voltage (I–V) characteristics of the photodiode were obtained under different illumination intensities. The electrical, sensitivity, and photoresponsivity properties of Co/CR/p-Si/Al photodiode were investigated using the current–voltage and capacitance–voltage measurements. While the calculated barrier height (Φb) and ideality factor (n) were 0.58 eV and 1.52 under the dark, these values were 0.55 eV and 1.62 under the 400 mW cm−2, respectively. The exponent of photocurrent was found to be 1.10. This value indicates that the photodiode exhibited a linear photocurrent variation with power of the light. It was found that the interface-state intensity of the photodiode decreased from 1.64 × 1015 to 8 × 1012 eV−1 cm−2 under the 400 mW cm−2 light intensity. The rectification rate of photodiode (RR) of the photodiode was found under the dark and illumination. All experimental results indicate that the photodiode exhibits a photoconducting characteristic.

Effect of illumination intensity on the characteristics of Cu(acac)2/n-Si photodiode

Thermally evaporated copper (II) acetylacetonate Cu(acac)2 thin film deposited on the n-Si wafer was used for light detection. The microstructural properties of copper (II) acetylacetonate thin film were investigated using high-resolution transmission electron microscope technique. A polycrystalline nature of Cu(acac)2 film with a clearly resolved lattice fringes were obtained. The optical properties of the thin film deposited on an n-type silicon substrate were investigated using spectroscopic ellipsometry technique which suggested UV and visible light absorption of copper (II) acetylacetonate. The I-V characteristics of the fabricated photodiode were investigated in dark and under different light illumination intensities. The main diode parameters were determined using the Thermionic emission theory and modified Norde's method. The present architecture showed a good response to halogen lamb light, where the estimated values of rise and fall time at 80 mW/cm2 were about 339 ms and 1046 ms, respectively. Furthermore, C-V measurements for the fabricated device were performed in dark at different frequencies.

Effect of illumination intensity on photosynthesis assisted anaerobic digestion of cattle manure leachate for enhanced biogas production

Bio-methane is an attractive energy source which can be produced by utilization of waste sources through anaerobic digestion process. However, low methane content of biogas hinders its effective applications. In this study, photosynthesis reaction was used concurrent with anaerobic digestion as an effective controlling mechanism for biogas up-grading and enhancement of its methane content. For this purpose, photosynthesis assisted anaerobic digestion of cattle manure leachate was conducted at light intensities of 2700, 5900 and 9600 Lux in batch bioreactors. The effect of illumination intensity on COD removal, biogas composition and yield was investigated. Moreover, the concentrations of phosphate and nitrate as major intermediates in anaerobic digestion and photosynthesis processes were monitored. Results showed that COD removals of 51, 53 and 54% and specific methane yields of 0.058, 0.036 and 0.024 L CH4/g CODremoved were obtained for light intensities of 2700, 5900 and 9600 Lux, respectively. At light intensity of 2700 Lux, the highest methane content of almost 90% and nitrate removal of 48% were achieved. At this condition, the concentration of methane in biogas was high enough to be considered as a prospective energy carrier.

Nano step height measurement using an optical method

This paper presents two optical methods for measuring nano step height standards and discusses the deviations in the measurements in detail. A white light interference (WLI) microscope and spinning disk confocal (SDCF) microscope were used in the experiments. The effect of illumination intensity and the standard’s surface reflectivity were studied and analyzed. The surface properties of the step height standard were ameliorated using secondary coating technology. The experimental results demonstrated that the secondary coating technology effectively improved the measurement accuracy of the SDCF microscope. The WLI microscope measured accurately both before and after a secondary coating was applied.

Effect of illumination intensity and inhibition of carotenoid biosynthesis on assembly of peripheral light-harvesting complexes in purple sulfur bacteria Allochromatium vinosum ATCC 17899

Effect of illumination intensity and inhibition of carotenoid biosynthesis on assemblage of different spectral types of LH2 complexes in a purple sulfur bacterium Allochromatium (Alc.) vinosum ATCC 17899 was studied. Under illumination of 1200 and 500 lx, the complexes B800-850 and B800-840 and B800-820 were assembled. While rhodopine was the major carotenoid in all spectral types of the LH2 complex, a certain- increase in the content of carotenoids with higher numbers of conjugated double bonds (anhydrorhodovibrin and didehydrorhodovibrin) was observed in the B800-820 complex. At 1200 lx, the cells grew slowly at diphe- nylamine (DPA) concentrations not exceeding 53 .iM, while at illumination intensity decreased to 500 Ix they could grow at 71 jiM DPA (DPA cells). Independent on illumination level, the inhibitor is supposed to impair the functioning of phytoine synthetase (resulting in a decrease in the total carotenoid content) and of phyto- ine desturase, which results in formation of neurosporene hydroxy derivatives and ;-carotene. In the cells grown at 500 lx, small amounts of spheroidene and.OH-spheroidene were detected. These carotenoids were originally found under conditions of carotenoid synthesis inhibition in bacteria with spirilloxanthin as the major carotenoid. Carotenoid content in the LH2 complexes isolated from the DPA cells was -15% of the control (without inhibition) for the B800-850 and -20%of the control for the B800-820 and B800-840 DPA complexes. Compared to the DPA pigment-containing membranes, the DPA complexes were enriched with -carotenoids due to- disintegration of some carotenoid-free complexes in the course of isolation. These results support the supposition that some of the B800-820, B800-840, and B800-850 complexes may be Assembled in the cells of Alc. vinosum ATCC 17899 without carotenoids. Comparison of the characteristics obtained for Alc. vinosum ATCC 17899 and the literature data on strain D of the same bacteria shows that they belong to two different strains, rather than to one as was previously supposed.

Synthesis and characterization of DSSC by using Pt nano-counter electrode: photosensor applications

Pt electrode prepared by chemical method has been employed as counter electrode in dye-sensitized solar cell. TiO2 nanomaterial was deposited on fluorine-doped tin oxide substrate to be used as photoanode. Structure of the TiO2 and Pt films was investigated by atomic force microscope. The effect of illumination intensity on the photovoltaic parameters such as open circuit voltage, short circuit current density, output power, fill factor and efficiency of these cells was investigated in the range 2.5–130 mW/cm−2. The cell efficiency is stable above 70 mW/cm2. The fill factor is almost constant all over the studied range of illumination intensity. Impedance spectroscopy of the studied device as the summary measurements of the capacitance–voltage, conductance–voltage and series resistance–voltage characteristics were investigated in a wide range of frequencies (5 kHz–1 MHz). At low frequencies, the capacitance has positive values with peak around the origin due to the interfaces. At 200 and 300 kHz, the capacitance is inverted to negative with further increasing of the positive biasing voltage. Above 400 kHz, C–V profile shows complete negative behavior. Also, the impedance–voltage and phase–voltage characteristics were investigated. This cell shows a new promising device for photosensor applications due to high sensitivity in low and high illuminations.

Interfacial layer for efficiency improvement of solution-processed small molecular solar cells

A series of solution-processed small molecular solar cells (SMSCs) were fabricated with 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] (DIB-SQ) and [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as the active layer. The cells with MoO3 as anode interfacial layer and LiF as cathode interfacial layer have the maximum power conversion efficiency (PCE) 2.68%, with short circuit density (Jsc) of 8.2mA/cm2, open circuit voltage (Voc) of 0.9V and fill factor (FF) of 36.3% under 100mW/cm2 illumination intensity. The key parameters, including JscVoc, and FF of cells with MoO3 as anode interfacial layer and LiF as cathode interfacial layer, are improved about 54.7%, 26.9%, and 23.5% compared with these of cells using PEDOT:PSS as anode interfacial layer and LiF as cathode interfacial layer. The underlying reasons are mainly attributed to the effect of MoO3 layer on charge carrier collection and morphology of active layer. The effect of illumination intensity on the performance of cells was also discussed in detailed.

Organic Photovoltaic Cells Based on PbPc Nanocolumns Prepared by Glancing Angle Deposition

Organic small material lead phthalocyanine (PbPc) nanocolumns were prepared via glancing angle deposition (GLAD) on indium tin oxide (ITO) coated glass substrates. Organic electron acceptor materials fullerene (C60) was evaporated onto the nanocolumn PbPc thin films to prepare heterojunction structure ITO/PbPc/C60/Bphen/Al organic photovoltaic cells (OPVs). It is worthwhile to mention that C60molecules firstly fill the voids between PbPc nanocolumns and then form impact C60layer. The interpenetrating electron donor/acceptor structure effectively enhances interface between electron donor and electron acceptor, which is beneficial to exciton dissociation. The short circuit current density (Jsc) of organic photovoltaic devices (OPVs) based on PbPc nanocolumn was increased from 1.19 mA/cm2to 1.74 mA/cm2, which should be attributed to the increase of interface between donor and acceptor. The effect of illumination intensity on the performance of OPVs was investigated by controlling the distance between light source and sample, and theJscof two kind of OPVs was increased along with the increase of illumination intensity.

Effect of illumination intensity on cell parameters of a silicon solar cell

The effect of illumination intensity P in on the cell parameters of a silicon solar cell has been investigated based on one diode model. The variation of slopes of the I–V curves of a cell at short circuit and open circuit conditions with intensity of illumination in small span of intensity has been applied to determine the cell parameters, viz. shunt resistance R sh , series resistance R s , diode ideality factor n and reverse saturation current I 0 of the cell. The dependence of cell parameters on intensity has been investigated for a fairly wide illumination intensity range 15–180 mW/cm 2 of AM1.5 solar radiations by dividing this intensity range into a desirable number of small intensity ranges for measurements of the slopes of the I–V curves at short circuit and open circuit conditions. Initially R sh increases slightly with P in and then becomes constant at higher P in values. However, R s , n and I 0 all decrease continuously with P in , but the rate of decrease of each of these becomes smaller at higher P in values. Theoretical values of open circuit voltage V oc , curve factor CF and efficiency η calculated using the cell parameters determined by the present method match well with the corresponding experimental values.

Effect of illumination intensity and temperature on open circuit voltage in organic solar cells

The effect of illumination intensity and temperature on open circuit voltage (Voc) in organic photovoltaic devices has been investigated. Voc is observed to saturate at high illumination intensities. The illuminated J-V characteristics at different intensities intersect the dark characteristic at a single point. This intersection point is shown to be equal to the built-in voltage (Vbi) in the sample. A reduction in temperature shows increment in saturated Voc. This increment in saturated Voc is attributed to the variation of Vbi with temperature. A model has been presented that explains the observed behavior of Vbi at different temperatures.

Effect of illumination intensity and light application time on secondary organic aerosol formation from the photooxidation of α-pinene

Secondary organic aerosol (SOA) formation from hydroxyl radical (OH*) initiated photooxidation of alpha-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for alpha-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light application time, the concentration, and the size of SOA particles were also increased. In addition, the factors influencing the formation of SOA were discussed. In addition, this article compared the effect of alpha-pinene with that of toluene, and discussed the contribution of alpha-pinene to SOA formation.

Effect of illumination intensity on visual perception of turbidity

Colloidal size (0.15, 0.31, and 0.70 μm diameter) synthetic polymer microspheres were each suspended in liquids of three different colors (clear, tan and dark brown) at a range of concentrations. The latter two model solutions resembled colors found in light and dark beers. Samples were presented to panelists in a viewing box. Visual threshold determinations were made for each of the nine sample sets using the Ascending Method of Limits and bright illumination (1192 lux). Thresholds were much more similar expressed as turbidimeter observations than as either weight or number concentration, and ranged from 0.206 to 2.19 nephelos turbidity units (NTU). Panel mean thresholds increased as color intensity increased. Thresholds tended to be lower with the largest particles. Thresholds for each sample set were also determined with reduced illumination. Intermediate lighting intensity (592 lux) resulted in the lowest detection thresholds (0.176–0.829 NTU). The threshold results obtained with the lowest illumination (18 lux) were intermediate between those with the higher two illuminations (0.183–1.20 NTU).

Effect of illumination intensity and temperature on the I–V characteristics of n-C/p-Si heterojunction

Abstract Krishna et al. (Sol. Energy Mater. Sol. Cells 65 (2001) 163) have recently developed an heterojunction n-C/p-Si in order to achieve low cost and high-efficiency carbon solar cell. It has been shown that for this structure, the maximum quantum efficiency (25%) appears at wavelength λ (600 nm). In this paper, the dependence of I – V characteristics of this heterojunction solar cell on illumination intensity and temperature has been systematically investigated. An estimation of the stability of the solar cell with temperature has been made in terms of the temperature coefficient of I sc and V oc . The intensity variation study has been used to estimate the series resistance R s of the solar cell. The effect of illumination intensity on I – V of n-C/p-Si heterojunction is more complex because the carrier lifetime and the carrier mobility of amorphous carbon are small and also because drift of carriers by built-in electric field plays an important role in these cells. Therefore, the conventional analytical expression for I – V characteristic is not applicable to such solar cells. These structures will not obey the principle of superposition of illuminated and dark current. The experimental results have been analysed by developing empirical relation for I – V . The temperature sensitivity parameters α , the change in I sc and β , the change in V oc per degree centigrade have been computed and are found to be 0.087 mA/°C and 1 mV/°C, respectively. This suggests that the heterojunction n-C/p-Si has good temperature tolerance. The value of series resistance has been estimated from the family of I – V curves at various intensities. The R s is found to be ≈12 Ω, which is on the higher side from the point of view of photovoltaic application.

Probe of Field Collapse in a-Si:H Solar Cells

AbstractWe study the effect of illumination intensity on solar cell performance in a-Si:H solar cells. We find that the fill factor strongly depends on light intensity. As we increase the illumination intensity from low levels to one sun we observe a decrease in fill factor of approximately 15% in as grown cells. We attribute this effect to electric field collapse inside the cell. We propose that photogenerated space charge (free and trapped charge) increases with light intensity and causes field collapse. We describe the origin of space charge and the associated capacitance - photocapacitance. We measure the photocapacitance as a barometer to probe the collapsed field. We obtain a good agreement between photocapacitance experiments and theory. We also explore the light intensity dependence of photocapacitance and explain the decrease of FF with the increasing light intensity.

New thermoacoustic technique for contactless measurements on semiconductors

The authors prove that changes in photocarrier concentration can be observed optically, when low-frequency modulated illumination is used. Changes in the photocarrier concentration cause variations of the carrier thermal conductivity which are detected by a thermoacoustic contactless technique using a one-arm optical bridge. The effect of illumination intensity on the thermoacoustic signal in CdS was studied.

Effect of illumination intensity on the response of the hide beetle, Dermestes maculatus, to aggregation pheromone

Adult hide beetles, Dermestes maculatus, are strongly photonegative and tend to aggregate in dark places. Another factor which can cause their aggregation is an aggregation pheromone from their faeces. A two-choice test was used to investigate the insects' reaction to pheromone in various illumination conditions. Beetles were placed inside Petri dishes and given a choice between the dark part of the dish, containing control filter-paper strip, and the illuminated part of the dish, containing a pheromone-treated filter-paper strip. A series of choice tests was performed at each of six levels of illumination: darkness, 1, 10, 100, 1000 and 10,000 lux. The behaviour of insects tested in such circumstances proved to depend on the intensity of illumination. In darkness and in dim light most of the insects were aggregated around the pheromone-treated strip whereas the highest illumination intensity used in tests caused the aggregation of most insects in the dark part of the dish, around the control strip.