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• One dimensional photonic ribbon structure is disclosed to enhance an efficiency of Solar cell. • Band gap of photonic structure is lucidly explained at all visible colours. • Principle of intrinsic mechanism in tandem solar cell is divulged. The silicon-based 1D photonic structure is proposed in this research to realize an intermediate layer, which could be used in tandem solar cell, where 1 D photonic structure deals with a silicon ribbon with having 10 number of circular periodic air hole on it. Further, the principle of realization of the present intermediate layer is based on the generation of photonic band gap with respect to the visible light, which is evaluated with the help of the plane wave expansion method. Finally, photonic band gap analysis confirms that the proposed one-dimensional photonic ribbon structure can be a suitable layer to introduce in a tandem solar cell to envisage better efficiency. [ABSTRACT FROM AUTHOR]

Abstract Solar cells based on CuInGaSe 2 (CIGS) have attained the highest record efficiency (22.9%) among thin film solar cells. CIGS is formed by the appropriate mixing of CuInSe 2 (CIS) which has a bandgap around 1 eV and CuGaSe 2 (CGS) which has a bandgap around 1.7 eV. These bandgaps are close to the optimal values for two-junction tandem solar cells. Therefore, CGS on CIGS or CGS on CIS tandem cells should be attractive and viable to achieve high efficiency and cost-effective thin film solar cells. In this work, a simple unified analytical model is used to design two-terminal and four-terminal CGS/CIGS tandem solar cells, establishing a realistic value for the expected efficiency in each case. Short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency, are determined as a function of the CGS and CIGS acceptor impurity concentrations, back surface recombination velocities, minority carrier diffusion lengths, and absorber layer thickness. It is shown that realistic efficiencies over 30% can be achieved under one sun AM1.5 spectrum for both of the terminal configurations, but the optimum composition for the CIGS sub-cell should be different depending on the respective tandem cell configuration. [ABSTRACT FROM AUTHOR]

The wide photon absorption range of tandem solar cells (TSCs) allows them to deliver higher efficiencies than single-junction solar cells. The top cell with a wide bandgap absorbs the higher energy photons, while the bottom cell with a relatively low bandgap absorbs the filtered lower energy photons. However, for cheap, efficient, and long-lasting solar cells, the design must incorporate the top and bottom cell absorber layers with an appropriate band gap. In this context, this article proposes all-perovskite tandem solar cells with suitable perovskite partners as active materials in both the upper (band gap 1.68 eV) and the lower (band gap 1.16 eV) sub-cell. This research has retrieved the calibrated top cell from a previous publication, and the bottom cell has been designed, calibrated, and optimised. The filtered spectrum of the upper cell is evaluated at different perovskite thicknesses and fed to the lower cell to set up a tandem configuration. Subsequently, the current- matching technique has been used to study the tandem short-circuit current density (J SC) at different thicknesses of both sub-cells, followed by current density-voltage (J-V) curve. A total of ten tandem J-V curves are constructed and corresponding PV parameters are obtained to obtain the optimized efficiency of 33.8% with an open circuit voltage (V OC) of 2.15 V, a fill factor (FF) of 78.87% and a J SC of 20 mA.cm−2. The reported results will open the door for future development of highly efficient and low-cost monolithic two-terminal tandem devices. [ABSTRACT FROM AUTHOR]

Tunable bandgap and excellent optoelectronic properties can make perovskite solar cells (PSC) achieve high power conversion efficiencies in single junction as well as tandem architecture. In this work, 3 types of perovskite solar cell architectures i.e., single-junction, all-perovskite tandem and all-perovskite triple-junction, are modeled in SunSolve. The optimized layer thickness, reflection/parasitic absorptions, quantum efficiency, IV characteristics and power conversion efficiencies (PCE) of each cell are analyzed in detail. The single-junction solar cell of CH 3 NH 3 PbI 3 with bandgap of 1.55 eV produces the PCE of 21.4%. The all-perovskite tandem solar cell of (CH 3 NH 3) 0.9 Cs 0.1 Pb(I 0.6 Br 0.4) 3 (1.82 eV) as top sub-cell and CH 3 NH 3 Pb 0.5 Sn 0.5 I 3 (1.22 eV) as bottom sub-cell exhibits a PCE of 26.06%. While the all-perovskite triple-junction solar cell of FA 0.83 Cs 0.17 Pb(I 0.7 Br 0.3) 3 (1.94 eV) as top sub-cell, CH 3 NH 3 PbI 3 (1.55 eV) as middle sub-cell and CH 3 NH 3 Pb 0.5 Sn 0.5 I 3 (1.22 eV) as bottom sub-cell has the remarkable PCE potential of 28.38%. This work guides towards multi-junction solar cells based on perovskite materials for the low-cost utilization of solar energy. [ABSTRACT FROM AUTHOR]

Abstract: In order to considerable enhancement of the efficiency of silicon solar cells, in this paper, for the first time, we present a new proposal for silicon based tandem solar cells. For investigation of this idea, we have evaluated the characteristics of 3C–SiC/Si crystalline tandem solar cells connected series by a tunneling junction, under air mass 1.5 global irradiance spectrums. A 2D simulation including the effects of surface passivation, back surface field (BSF), and carrier tunneling have been performed to obtain the optical and electrical characteristics of single junction silicon, 3C–SiC, and finally the tandem cells. The obtained data illustrate that the best design parameters considering the experimental limitations can be obtained. High energy conversion efficiency for the proposed structure of 26.09% has been achieved for 3C–SiC/Si tandem structure driven by 20.49% and 17.86% conversion efficiencies of single junction Si and 3C–SiC solar cells, respectively. Our results justifies that the higher conversion efficiency of the Si-based tandem structure compared with 3C–SiC and Si cells stems from enhancement of open circuit voltage and fill factor parameter at the hands of decrease in short circuit current limited by the top 3C–SiC cell. [Copyright &y& Elsevier]

This paper proposes a methodology of optimum power point tracking for tandem solar cell technology to generate green energy. It utilizes an active optical solar tracking and concentrating system, employing ultraviolet (UV) parts: UVA and UVB (280–400 nm), from the solar irradiations. Hence, devises a methodology to avoid complex maximum power point tracking hardware and presents a use of UV solar irradiation. It can be used as an alternative to the conventional concentrated photovoltaic system as well. The performance of the proposed system is also optimized for its output power fixed at a required value of the interest with fewer fluctuations and heating effects. Working of the proposed system is based on a solar irradiance, intensity-dependent axial movement of the light funnel with its variable aperture, and the W/m2 created by a Fresnel lens. The proposed system finds its utility for places where the UV index is recorded at its highest ≥ +11 allowing UV radiations to reach the earth at high levels. The proposed approach is validated, to fulfill fixed energy demand of a thermolysis process against its constant output power claim. For the purpose, firstly absorption response of a quadruple junction solar cell is investigated and made sure that it is capable of operating on UVA and UVB. Secondly, to achieve a constant irradiance level on solar panel surface, control systems along three-axes are designed based on the least-squares optimization criterion to minimize the tracking error and keep the irradiation fixed to a reference value of 1000 W/m2. [ABSTRACT FROM AUTHOR]

The production and commercialization of solar cells should meet such social criteria as price affordability, environment friendly, stability, and high efficiency of established materials.Various solar cells have been suggested and investigated in the past; but in this work, CZTS-Perovskite tandem solar cell having a model "CZTS/PSC/CZTS/ZnO/FTO" was taken from the reported work as a reference. Furthermore, inserting the CdS as a buffer layer with the new model, "CZTS/PSC/CZTS/CdS/ZnO/FTO" was simulated with SCAPS-1D software. Moreover, it was observed that the effect of CdS enhanced the tandem device efficiency from the base case of 22.57% without the CdS buffer layer to 25.95% with CdS and carried out further optimizations. This improvement is beneficial for CZTS-Perovskite tandem solar cells. The J-V characteristics curve and energy band diagram was generated using this model. Later on, with this new model, the effect of the thickness of CZTS layer on the solar cell's performance was investigated. So, the thickness also significantly affected the characteristic parameters of the solar cell as well as the J-V characteristics curve. Hence, a photo-conversion efficiency of 25.95% with Voc 1.18 V, Jsc 24.79 mA/cm2, and FF 88.36%, the obtained results demonstrating that the proposed CZTS-perovskite tandem solar cell may concrete the way for the production of low-cost and more efficient photovoltaic applications. [ABSTRACT FROM AUTHOR]

In this study, the performances of a-Si: H(n-i-p) /μc-Si: H(n-i-p) tandem solar cell based on hydrogenated amorphous silicon (a-Si: H) and hydrogenated microcrystalline silicon (μc-Si: H) with thinner active layers were investigated by using numerical simulation. For simulation, a one-dimensional computer code AMPS-1D was used to investigat the effect of the top single cell n+ layer nature, the effect of the top single cell n+ μc-Si: H layer doping concentration (ND) and, the effect of the two active layers thicknesses, i-a-Si: H layer and i-μc-Si: H layer on the performances of the tandem cell. However, the merit figures, like J(V) characteristics at dark and under illumination, the electric fields, the energy band diagrams and, the cell output parameters are calculated and investigated. According to our calculations it is found that, by using a n+μc-Si: H layer with a doping concentration value ND = 1019 cm−3 instead of a n+ a-Si: H layer in the n-i-p top single cell the tandem solar cell performances were performed. It is also obtained, a values of 50 nm and 600 nm for the active layers i-a-Si: H and i-μc-Si: H thicknesses, respectively, are recommended for a-Si: H/μc-Si: H tandem solar cell good performances. Lastly, the tandem solar cell with top single cell n+μc-Si :H layer and with a thinner active layers thicknesses has the higher output parameters (J SC =10.52 mA/cm2, V OC =1414 mV, FF = 80.2 % and, the efficiency = 12.14 %). [ABSTRACT FROM AUTHOR]

In this study, the performances of a-Si: H(n-i-p) /μc-Si: H(n-i-p) tandem solar cell based on hydrogenated amorphous silicon (a-Si: H) and hydrogenated microcrystalline silicon (μc-Si: H) with thinner active layers were investigated by using numerical simulation. For simulation, a one-dimensional computer code AMPS-1D was used to investigat the effect of the top single cell n+ layer nature, the effect of the top single cell n+ μc-Si: H layer doping concentration (ND) and, the effect of the two active layers thicknesses, i-a-Si: H layer and i-μc-Si: H layer on the performances of the tandem cell. However, the merit figures, like J(V) characteristics at dark and under illumination, the electric fields, the energy band diagrams and, the cell output parameters are calculated and investigated. According to our calculations it is found that, by using a n+μc-Si: H layer with a doping concentration value ND = 1019 cm−3 instead of a n+ a-Si: H layer in the n-i-p top single cell the tandem solar cell performances were performed. It is also obtained, a values of 50 nm and 600 nm for the active layers i-a-Si: H and i-μc-Si: H thicknesses, respectively, are recommended for a-Si: H/μc-Si: H tandem solar cell good performances. Lastly, the tandem solar cell with top single cell n+μc-Si :H layer and with a thinner active layers thicknesses has the higher output parameters (J SC =10.52 mA/cm2, V OC =1414 mV, FF = 80.2 % and, the efficiency = 12.14 %). [ABSTRACT FROM AUTHOR]