Improved Optical and Electronic Properties of Single-Layer MoS2 by Co Doping for Promising Intermediate - Band Materials

Owing to its unique optical and electronic characteristics, two-dimensional MoS2 has been widely explored in the past few years. Using first-principle calculations, we shed light on that the substitutional doping of Co can induce the half-filled intermediate states in the band gap of monolayer MoS2. The calculated absorption spectrum presents an enhancement of the low-energy photons (0.8 eV–1.5 eV), which is desired for intermediate-band solar cells. When the doping concentration increases, the reflectivity of the infrared and visible light (0.8 eV-4.0 eV) reduces, resulting in an improved photovoltaic efficiency of the material. Our results shed light on the application of heavily Co-doped MoS2 as intermediate band solar cell material.

Band Gap of Pb(Fe0.5Nb0.5)O3 Thin Films Prepared by Pulsed Laser Deposition

Ferroelectric materials have gained high interest for photovoltaic applications due to their open-circuit voltage not being limited to the band gap of the material. In the past, different lead‑based ferroelectric perovskite thin films such as Pb(Zr,Ti)O3 (Pb,La)(Zr,Ti)O3 and PbTiO3 were investigated with respect to their photovoltaic efficiency. Nevertheless, due to their high band gaps they only absorb photons in the UV spectral range. The well-known ferroelectric PbFe0.5Nb0.5O3 (PFN), which is in a structure similar to the other three, has not been considered as a possible candidate until now. We found that the band gap of PFN is around 2.75 eV and that the conductivity can be increased from 23 S/µm to 35 S/µm during illumination. The relatively low band gap value makes PFN a promising candidate as an absorber material.

ANÁLISE DOS PARÂMETROS PARA GERAÇÃO DE ENERGIA SOLAR FOTOVOLTAICA NO ACRE, BRASIL

ANALYSIS OF PARAMETERS FOR PHOTOVOLTAIC SOLAR ENERGY GENERATION IN ACRE, BRAZILANÁLISIS DE PARÁMETROS PARA LA GENERACIÓN DE ENERGÍA SOLAR FOTOVOLTAICA EN ACRE, BRASILRESUMOEnergia solar é obtida através de placas solares fotovoltaicas com a função de captar a energia do sol e transformar em energia elétrica, aumentando a geração de energia solar nas regiões com maior captação de energia luminosa. Assim, neste artigo analisou-se os parâmetros para geração de energia solar fotovoltaica no Acre, Brasil. Coletou-se dados referentes a insolação, temperaturas máximas e mínimas, precipitação e umidade relativa no Instituto Nacional de Meteorologia, irradiação solar, no Centro de Referências para Energias Solar e Eólica Sérgio de S. Brito, regionais do Vale do Juruá e Vale do Acre, no período de 2015-2020. As análises foram quantitativas, utilizando o cálculo da média e cálculo do plano inclinado. Na comparação das regionais, o Vale do Acre apresentou melhores resultados para geração de energia solar e com um ângulo com a maior média diária anual de irradiação solar, considerando-se projetar-se células fotovoltaicas na regional. O trabalho apresenta que o Acre possui bastante insolação e irradiação solar, indicando alto potencial de geração de energia solar para as regionais do estado.Palavras-chave: Eficiência Fotovoltaica; Radiação Solar; Temperatura da Célula Fotovoltaica; Irradiação.ABSTRACTSolar energy is obtained through photovoltaic solar panels with the function of capturing the sun's energy and transforming it into electrical energy, increasing the generation of solar energy in regions with greater capture of light energy. Thus, the parameters for the generation of photovoltaic solar energy in Acre, Brazil were analyzed. Data on insolation, maximum and minimum temperatures, precipitation and relative humidity were collected at the National Institute of Meteorology, solar irradiation, at the Reference Center for Solar and Wind Energy Sérgio de S. Brito, regions of Vale do Juruá and Vale do Acre, in the period 2015-2020. Analyzes were quantitative, using mean calculation and inclined plane calculation. When comparing the regions, Vale do Acre presented better results for solar energy generation and with an angle with the highest annual daily average of solar irradiation, considering the project of photovoltaic cells in the region. The work shows that Acre has a lot of insolation and solar irradiation, indicating a high potential for generating solar energy for the regional regions of the state.Keywords: Photovoltaic Efficiency; Solar Radiation; Photovoltaic Cell Temperature; Irradiation.RESUMENLa energía solar se obtiene a través de paneles solares fotovoltaicos con la función de captar la energía del sol y transformarla en energía eléctrica, aumentando la generación de energía solar en las regiones con mayor captación de energía luminosa. Así, se analizaron los parámetros para la generación de energía solar fotovoltaica en Acre, Brasil. Los datos sobre insolación, temperaturas máximas y mínimas, precipitación y humedad relativa fueron recolectados en el Instituto Nacional de Meteorología, irradiación solar, en el Centro de Referencia de Energía Solar y Eólica Sérgio de S. Brito, regiones de Vale do Juruá y Vale do Acre, en el período 2015-2020. Los análisis fueron cuantitativos, utilizando cálculo de medias y cálculo de plano inclinado. Al comparar las regiones, Vale do Acre presentó mejores resultados para la generación de energía solar y con un ángulo con el promedio diario anual más alto de irradiación solar, considerando el diseño de células fotovoltaicas en la región. El trabajo muestra que Acre tiene mucha insolación e irradiación solar, lo que indica un alto potencial de generación de energía solar para las regiones regionales del estado.Palabras clave: Eficiencia Fotovoltaica; Radiación Solar; Temperatura de la Celda Fotovoltaica; Irradiación.

Rancang Bangun Hidroponik Dengan Bantuan Pompa Bertenaga Surya

Agriculture traditionally still uses large areas of land with relatively large amounts of water. The application of solar energy is one of the uses of new and renewable energy. This research uses a 50 Wp photovoltaic cell, battery, solar charge controller, DC stepdown, DC pump and hydroponic frame. The stages of the research are the design of the tools, the calculation of the power required by the tools, the manufacture of the tools, the collection of data and the analysis of the data. The data collected is temperature, sunlight intensity, electric power, electrical energy, water discharge, and photovoltaic efficiency. The data were processed and analyzed in an exploratory manner. Based on the results of the research conducted, the lowest average temperature was 25.33 C and the highest was 33.70 C with the highest average light intensity of 920.26 w/m2 at 12.00 WIB. The relationship between temperature and light intensity with a value of R2 of 0.7594. The highest average electrical energy obtained by polycrystalline is 30.44Wh. The water lost from the hydroponic system is 0.03%. The efficiency of photovoltaic cells is 10.09%–15.72%. Keywords: DC pump, hydroponics, light intensity, photovoltaic

Cost effective dye sensitized solar cell based on novel Cu polypyrrole multiwall carbon nanotubes nanocomposites counter electrode

In order to replace Pt CE in dye sensitized solar cell (DSSC) with simple and low cost, copper polypyyrol functionalized multiwall carbon nanotubes (Cu-PPy-FWCNTS) nanocomposite CE was fabricated by two step electrodeposition method on the stainless-steel substrate. The surface morphology, electrical conductivity, electrochemical properties of Cu-PPy-FWCNTS nanocomposite CE electrodes were observed by using verity of techniques such as scanning electron microscopy, a four-probe method and electrochemical workstation. The Fourier transform infrared (FTIR) spectroscopy confirms the presence of FMWCNTS into PPy-FMWCNTS nanocomposite and XRD analysis verified the Cu nanostructures had come into being. The cyclic voltammogram and Tafel polarization measurement demonstrated that solution processed Cu-PPy-FWCNTS nanocomposites CE had smaller charge transfer resistance Rct (4.31 Ω cm2) and higher electrocatalytic performance for I3−/I− redox solution. Finally, the photovoltaic efficiency of DSSC assembled with Cu-PPy-FWCNTS nanocomposite CE and Platinized CE were compared. The results revealed that the photovoltaic efficiency of DSSC with Cu-PPy-FWCNTS nanocomposites CE reached (7.1%), which is superior to Platinized CE (6.4%). The higher photovoltaic efficiency of the Cu-PPy-FMWCNTS film is due to copper nanostructures that lead to higher cathodic current density (2.35 mA/cm2). The simple fabrication method, excellent electrocatalytic and photovoltaic properties permit the Cu-PPy-FWCNTS nanocomposites credible alternative CE to save the cost of DSSC.