High Performance Dye Sensitized Solar Cells by Plasmonic Enhancement of Silver Nanoparticles in ZnO Photoelectrode with Betanin Pigment

Metal nanoparticles (NPs) introduced in sensitive places in Dye Sensitized Solar Cells (DSSCs) has demonstrated superior performance due to surface plasmon resonance effect. Herein, a systematic investigation by introducing plasmonic silver nanoparticles (AgNPs) in the photoanode of DSSCs with Zinc oxide (ZnO) is investigated. The broadening of the absorption band in the visible region is made possible using the natural pigments betanins. The combined effect of UV-visible absorption spectroscopy, XRD technique, SEM and solar simulator were used to explore the surface plasmon resonance effect. The ZnO photoanode without Ag- NPs shows a Power Conversion Efficiency (PCE) of 0.156 %, Current Density (Jsc) of 0.477 mAcm-2, Open Circuit Voltage (Voc) of 0.762 V and Fill Factor (FF) of 0.431. On coating AgNPs on the pristine photoanode, the PCEs were improved significantly as compared with the pure ZnO based device. The AgNPs were deposited in cycles (2 cycles, 4 cycles and 6 cycles). The device with 2 cycles of Ag NPs, shows a PCE of 0.373 % which demonstrates an enhancement of 2.39 times to that of the prestine device.Also depositing 4 cycles of AgNPs results to PCE of 0.290 % which shows a leading of 0.134 %  ahead of the reference PCE. With 6 cycles of AgNPs deposited on the photoanode of bare ZnO NPs, it results to PCE of 0.244%, FF of 0.592, Jsc of 0.572 mAcm-2 and Voc of 0.722 V which also shows an enhancement of - 1.56 times, 1.37 times and 1.20 times in PCE, FF and Jsc over the device lacking AgNPs. These results show significant increment in performances of all the devices with silver inclusion. The performance is attributed to the reduced recombination of electron–hole pairs due to the Ag-ZnO junction and the generation of intense electric fields at the immediate vicinity of the sensitizer, resulting in enhanced light absorption

Cohesive energies calculation of Gallium-Arsenide and Aluminium-Arsenide: DFT study

A detailed calculation of quantum mechanical first principle theoretical studies of Gallium-Arsenide (GaAs) and Aluminum-Arsenide (AlAs) based on Density Functional Theory (DFT) within the Local Density Approximation (LDA) for the exchange-correlation potential has been performed using Fritz Haber Institute Ab-initio Molecular Simulations (FHI-aims) code. The code has several input parameters in which some of the variables were optimized. The cohesive energies of GaAs and AlAs were calculated within LDA of Perdew Wang of the density functional theory. The results obtained from the computation of the cohesive energies of GaAs and AlAs were 6.94 eV and 8.79 eV respectively which revealed a good agreement in theexchange correction functional when compared to the experimental values of 6.75 eV and 8.00 eV for GaAs and AlAs respectively. These energies are within reasonable percentage errors of 2.6% and 9.9% respectively. This indicate that GaAs can exhibit high transport property of the electron in the semiconductor which makes it suitable for optoelectronics devices and the AlAs indicate their potentials can be used in high temperature and strong electric fields device applications

Effect of Irradiation on Vitamin C, Acidity and Moisture Content of Mango Fruits with Gamma Ray from Cobalt-60 Source

In this study four varieties of mango fruits were irradiated with Gamma ray from Cobalt-60 source at different dose points of 50 Gy, 100 Gy, 300 Gy and 800 Gy in order to investigate the effect of irradiation on vitamin C, titreable acidity and moisture content. Studies indicate that the dose point of 0.05 KGy (sample A) and 0.10 KGy (sample B) gained an average vitamin C content of 6.88% and 6.27% respectively while the dose point of 0.30 KGy showed no loss or gained of vitamin C content and the dose point of 0.80 KGy (sample D) loss 56.25% of vitamin C as compared to reference point (un-irradiated or control sample). The values of titreable acidity which was high on day 2 decreases at day 10 and later increases at day 17. This is attributed to an increase in pulp acidity which occurred as the ripening process proceeds. Also a study reveals that irradiation has no effect on moisture content of mango fruit but can delay the rate of respiration thus the ripening and shelf life

Effect of Biosynthesized Silver Nanoparticles on The Optical, Structural, and Morphological Properties of TiO2 Nanocrystals

The development of efficient metal doped semiconductors for Photovoltaic applications has gained a lot of research attention. In this present paper, pure and silver nanoparticles (AgNPs)-modified TiO2 nanocrystals (NCs) with different amount of AgNPs (say 50, 100, 150, 200, and 250 µL) were achieved and the effects of AgNPs on the TiO2 NCs were explored systematically. The optical, structural and morphological properties were probed using UV-visible spectrophotometer, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results of the optical studies showed a characteristic peak of TiO2 and the redshifting of the peak position was observed by introducing AgNPs. The synergetic effects from AgNPs and TiO2 results to diminished band gap. The XRD result confirmed the formation of a tetragonal anatase TiO2 phase with a decrease in crystallite size with increasing AgNPs content. The SEM images show enhanced nucleation and film growth with presence of shining surface which can be seen to contribute to good photon management by enhancing light scattering. The unadulterated TiO2 and AgNPs-modified TiO2 have spherical morphology and uniform size distribution ranging from 20 to 30 nm. This study established the view that surface modification of TiO2 with AgNPs is a viable approach towards achieving an efficient light photocatalyst

Development on inverted perovskite solar cells: A review

Recently, inverted perovskite solar cells (IPSCs) have received note-worthy consideration in the photovoltaic domain because of its dependable operating stability, minimal hysteresis, and low-temperature manufacture technique in the quest to satisfy global energy demand through renewable means. In a decade transition, perovskite solar cells in general have exceeded 25 % efficiency as a result of superior perovskite nanocrystalline films obtained via low temperature synthesis methods along with good interface and electrode materials management. This review paper presents detail processes of refining the stability and power conversion efficiencies in IPSCs. The latest development in the power conversion efficiency, including structural configurations, prospect of tandem solar cells, mixed cations and halides, films’ fabrication methods, charge transport material alterations, effects of contact electrode materials, additive and interface engineering materials used in IPSCs are extensively discussed. Additionally, insights on the state of the art and IPSCs' continued development towards commercialization are provided

Numerical Simulation of Copper Indium Gallium Diselenide Solar Cells Using One Dimensional SCAPS Software

The effect of multivalent defect density, thickness of absorber and buffer layer thickness on the performance of CIGS solar cells were investigated systematically. The study was carried out using Solar Cells Capacitance Simulator (SCAPS) code, which is capable of solving the basic semiconductor equations. Employing numerical modelling, a solar cell with the structure Al|ZnO : Al|In2S3|CIGS|Pt was simulated and in it, a double acceptor defect (-2/-1/0) with a density of 1014 cm-3 was set in the absorber in the first instance. This initial device gave a power conversion efficiency (PCE) of 25.85 %, short circuit current density (Jsc) of 37.9576 mAcm-2, Photovoltage (Voc) of 0.7992 V and fill factor (FF) of 85.22 %. When the density of multivalent defect (-2/-1/0) was varied between 1010 cm-3 and 1017 cm-3 the solar cells performance dropped from 26.81 % to 16.87 %. The champion device was with multivalent defect of 1010 cm-3 which shows an enhancement of 3.71 % from the pristine device. On varying the CIGS layer thickness from 0.4 um to 3.6 um, an increase in PCE was observed from 0.4 um to 1.2 um then the PCE began to decrease beyond a thickness of 1.2 um. The best PCE was recorded with thickness of 1.2 um which gave Jsc of 37.7506 mAcm-2, Voc of 0.8059 V, FF of 85.2655 %. On varying the In2S3 (buffer) layer thickness from 0.01 um to 0.08 um, we observed that there was no significant change in photovoltaic parameters of the solar cells as buffer layer thickness increased

SCAPS-1D simulated organometallic halide perovskites: A comparison of performance under Sub-Saharan temperature condition

Photovoltaic technology has been widely recognized as a means to advance green energy solutions in the sub-Saharan region. In the real-time operation of solar modules, temperature plays a crucial role, making it necessary to evaluate the thermal impact on the performance of the solar devices, especially in high-insolation environments. Hence, this paper investigates the effect of operating temperature on the performance of two types of organometallic halide perovskites (OHP) - formamidinium tin iodide (FASnI3) and methylammonium lead iodide (MAPbI3). The solar cells were evaluated under a typical Nigerian climate in two different cities before and after graphene passivation. Using a one-dimensional solar capacitance simulation software (SCAPS-1D) program, the simulation results show that graphene passivation improved the conversion efficiency of the solar cells by 0.51 % (FASnI3 device) and 3.11 % (MAPbI3 device). The presence of graphene played a vital role in resisting charge recombination and metal diffusion, which are responsible for the losses in OHP. Thermal analysis revealed that the MAPbI3 device exhibited an increased fill factor (FF) in the temperature range of 20–64 °C, increasing the power conversion efficiency (PCE). This ensured that the MAPbI3 solar cell performed better in the city and the season with harsher thermal conditions (Kaduna, dry season). Thus, MAPbI3 solar cells can thrive excellently in environments where the operating temperature is below 65 °C. Overall, this study shows that the application of OHP devices in sub-Saharan climatic conditions is empirically possible with the right material modification