Junction Configuration Effects on the Photovoltaic Parameters of a-Si/CZTS Solar Cells

Due to increased energy intensive human activities resulting accelerated demand for electric power coupled with occurrence of natural disasters with increased frequency, intensity, and duration, it becomes essential to explore and advance renewable energy technology for sustainability of the society. Addressing the stated problem and providing a radical solution has been attempted in this study. To harvest the renewable energy, among variety of solar cells reported, a composite a-Si/CZTS photovoltaic devices has not yet been investigated. The calculated parameters for solar cell based on the new array of layers consisting of a-Si/CZTS are reported in this study. The variation of i) solar cell efficiency as a function of CZTS layer thickness, temperature, acceptor, and donor defect concentration; ii) variation of the open circuit current density as a function of temperature, open circuit voltage; iii) variation of open circuit voltage as a function of the thickness of the CZTS layer has been determined. There has been no reported study on a-Si/CZTS configuration-based solar cell, analysis of the parameters, and study to address the challenges imped efficiency of the photovoltaic device and the same has been discussed in this work. The value of the SnO2/a-Si/CZTS solar cells obtained from the simulation is 23.9 %.

Deuterated N,N-dimethylformamide (DMF-d7) as An Additive to Enhance CsPbI3 Solar Cell Efficiency

Typically, DMSO and DMF are the two most commonly used co-solvents, however, their boiling points differ greatly and the volatilization rate is not consistent when the film is annealed and...

The Design and Optimization of an Anti-Reflection Coating and an Intermediate Reflective Layer to Enhance Tandem Solar Cell Photons Capture

We have theoretically demonstrated an efficient way to improve the optical properties of an anti-reflection coating (ARC) and an intermediate reflective layer (IRL) to enhance tandem solar cell efficiency by localizing the incident photons’ energy on a suitable sub-cell. The optimum designed ARC from a one-dimensional ternary photonic crystal, consisting of a layer of silicon oxynitride (SiON), was immersed between two layers of (SiO2); thicknesses were chosen to be 98 nm, 48 nm, and 8 nm, respectively. The numerical results show the interesting transmission properties of the anti-reflection coating on the viable and near IR spectrum. The IRL was designed from one-dimensional binary photonic crystals and the constituent materials are Bi4Ge3O12 and μc-SiOx: H with refractive indexes was 2.05, and 2.8, respectively. The numbers of periods were set to 10. Thicknesses: d1 = 62 nm and d2 = 40 nm created a photonic bandgap (PBG) in the range of [420 nm: 540 nm]. By increasing the second material thickness to 55 nm, and 73 nm, the PBG shifted to longer wavelengths: [520 nm: 630 nm], and [620 nm: 730 nm], respectively. Thus, by stacking the three remaining structures, the PBG widened and extended from 400 nm to 730 nm. The current theoretical and simulation methods are based on the fundamentals of the transfer matrix method and finite difference time domain method.

Investigation of non-imaging Fresnel lens prototyping with different manufacturing methods for solar energy application

Non-imaging Fresnel lenses have been playing an important role in improving the efficiency of the solar energy systems. Many researchers have been developing novel designs of Fresnel lenses to enhance the concentrator performance. To bring the complex design of a Fresnel lens from a conceptual theory to a real-life application while maintaining its efficiency, it is critical to find the optimum manufacturing method that achieves the best quality fabrication at low cost in the lab scale. This work will systematically investigate four advanced manufacturing methods for their lens-making capabilities, including pressure casting, hot embossing, 3D printing, and CNC machining. Six Fresnel lenses were fabricated by the four methods, which were tested in the lab by a solar simulator and a solar cell to demonstrate their performances. The CNC machining provides the best quality lab-scale Fresnel lens that enhances the solar cell efficiency by 118.3%. 3D printing and hot embossing methods are also promising for the fabrication of good performance lenses – increasing the solar cell efficiency by 40-70%. However, the 3D printed lens has the issue of material degradation on the long term. Although the pressure casting is the easiest manufacturing method, the performance of fabricated lens was the lowest.

Direct Plasmonic Solar Cell Efficiency Dependence on Spiro-OMeTAD Li-TFSI Content

The proliferation of the internet of things (IoT) and other low-power devices demands the development of energy harvesting solutions to alleviate IoT hardware dependence on single-use batteries, making their deployment more sustainable. The propagation of energy harvesting solutions is strongly associated with technical performance, cost and aesthetics, with the latter often being the driver of adoption. The general abundance of light in the vicinity of IoT devices under their main operation window enables the use of indoor and outdoor photovoltaics as energy harvesters. From those, highly transparent solar cells allow an increased possibility to place a sustainable power source close to the sensors without significant visual appearance. Herein, we report the effect of hole transport layer Li-TFSI dopant content on semi-transparent, direct plasmonic solar cells (DPSC) with a transparency of more than 80% in the 450–800 nm region. The findings revealed that the amount of oxidized spiro-OMeTAD (spiro+TFSI−) significantly modulates the transparency, effective conductance and conditions of device performance, with an optimal performance reached at around 33% relative concentration of Li-TFSI concerning spiro-OMeTAD. The Li-TFSI content did not affect the immediate charge extraction, as revealed by an analysis of electron–phonon lifetime. Hot electrons and holes were injected into the respective layers within 150 fs, suggesting simultaneous injection, as supported by the absence of hysteresis in the I–V curves. The spiro-OMeTAD layer reduces the Au nanoparticles’ reflection/backscattering, which improves the overall cell transparency. The results show that the system can be made highly transparent by precise tuning of the doping level of the spiro-OMeTAD layer with retained plasmonics, large optical cross-sections and the ultrathin nature of the devices.

Analytical Modeling of the Maximum Power Point with Series Resistance

This paper presents new analytical expressions for the maximum power point voltage, current, and power that have an explicit dependence on the series resistance. An explicit expression that relates the series resistance to well-known solar cell parameters was also derived. The range of the validity of the model, as well as the mathematical assumptions taken to derive it are explained and discussed. To test the accuracy of the derived model, a numerical single-diode model with solar cell parameters whose values can be found in the latest installment of the solar cell efficiency tables was used. The accuracy of the derived model was found to increase with increasing bandgap and to decrease with increasing series resistance. An experimental validation of the analytical model is provided and its practical limitations addressed. The new expressions predicted the maximum power obtainable by the studied cells with estimated errors below 0.1% compared to the numerical model, for typical values of the series resistance.

Thin-film Characterization

The third intended application for the proposed dispersion-encoded low-coherence interferometry is the evaluation of thin-film characteristics on substrate materials. Due to the usage of thin-film technologies in high-volume production in e.g. the photovoltaics and semiconductor industry, process monitoring becomes relevant in order to ensure functional parameters such as solar cell efficiency, [289]. In this context, film thickness as well as film homogeneity over large areas are important criteria for quality assurance.