Thin-film Photovoltaic Modules Research Articles

CO2 Electroreduction To Syngas With Tunable Composition In An Artificial Leaf.

Artificial leaves (a-leaves) can reduce carbon dioxide into syngas using solar power and could be combined with thermo- and biocatalytic technologies to decentralize the production of valuable products. By providing variable CO : H2 ratios on demand, a-leaves could facilitate optimal combinations and control the distribution of products in most of these hybrid systems. However, the current design procedures of a-leaves concentrate on achieving high performance for a predetermined syngas composition. This study demonstrates that incorporating the electrolyte flow as a design variable enables flexible production without compromising performance. The concept was tested on an a-leaf using a commercial cell, a Cu2 O:Inx cathodic catalyst, and an inexpensive amorphous silicon thin-film photovoltaic module. Syngas with CO : H2 ratio in the range of 1.8-2.3 could be attained with only 2 % deviation from the optimal cell voltage and controllable solely by catholyte flow. These features could be beneficial for downstream technologies such as Fischer-Tropsch synthesis and anaerobic fermentation.

Analysis of various degradations of five years aged mono c-Si, poly c-Si, and thin-film photovoltaic modules from rooftop solar installations in Dhaka’s tropical wet and dry climate conditions

This study evaluates the degradation of mono, poly, and thin-film silicon solar photovoltaic (PV) modules through visual and electrical measurements in Dhaka’s tropical wet and dry climate conditions. For this, several sites of rooftop solar PV installations in Dhaka, aged at least 5 years, were selected for field investigation. A visible inspection for visual degradation followed by experimental testing on various electrical characteristics of the PV modules installed on the rooftop using a portable Seaward I–V Tracer for measuring the electrical degradation was done. The electrical data were used to evaluate the degradation of short circuit current, open circuit voltage, fill factor, and maximum power in the field as compared to the nameplate values. Experimental results showed the varying types of visual degradation types such as visible cracks, snail trails, moisture intrusion, front glass, and discoloration for the investigated PV modules. The degradation of PV modules in terms of short circuit current was 0.7%/year for 85Wp mono c-Si, 7.6%/year for 150Wp poly c-Si, and 9.7%/year for 105Wp silicon thin-film, respectively. We believe this study would guide the maintenance of the solar PV systems installed on Dhaka city’s rooftop buildings.

Extraction and analysis of TCO coated glass from waste amorphous silicon thin film solar module

Considering the fast pace of the development of the Photovoltaic (PV) market and the installations in last two decades and also the increasing scarcity of resources for semiconductor materials, recycling waste PV modules including thin film is very important. Transparent conducting oxides (TCOs) are extensively used as front contact electrodes in thin-film photovoltaic devices. The paper presents, the new strategies developed to extract TCO coated glass from thin film amorphous silicon PV end-of-life modules. The recycling of thin film PV modules is based on a very simple approach that includes chemical, thermal and mechanical treatments. Optimised solutions of 1 M NaOH and 1 M KOH were used to extract TCO coated glass. The feasibility of the processing steps was demonstrated on laboratory scale size module and the etching rate for P, I, and N-layers of amorphous silicon is also studied. The extracted TCO was identified as fluorine-doped tin oxide (FTO) using X-ray diffraction and UV–visible spectroscopy techniques. The laser scribed FTO glass was successfully extracted without damaging the properties of the material. The extracted FTO has very low resistivity and sheet resistance in the range of 10−4 Ω-cm and 11.74 Ω/sq. respectively, has uniform transmission throughout the measured film surface of 2 cm2 in the visible region having bandgap ∼3.8eV. The recycling cost and current market value of the recycled FTO are also estimated for all the installed capacities of amorphous silicon. Considering the TCO properties, extracted FTO has the potential for its reuse in the fabrication of new thin film PV modules and other optoelectronic device applications as well.

The role of sustainability characteristics in the diffusion of renewable energy technologies

This paper aims to investigate the role of sustainability factors in the diffusion of solar photovoltaic (PV) technologies. A combined economic innovation-diffusion model that accounts for additional sustainability aspects is proposed. Two and three-stage least square methods were used for the empirical estimation, and the results were compared to a maximum entropy econometric estimation. The findings indicate that sustainability characteristics (i.e., cell efficiency) have a statistically significant positive effect on installed capacity in all solar PV technologies under analysis. Results show that multijunction PV modules have a learning rate of 17.1%, while Monojunction and the global aggregate have similar learning rates of 19.5% and 19%, respectively. Thin film PV modules have learning rates of 17.9% for the period 1991–2019. Cost reductions in solar PV modules can be largely attributed to learning-by-doing activities, the effects of learning by searching are ambiguous and depend both on the estimation methodology and the period under analysis. The study recognizes the difficulty in measuring sustainability characteristics, such as social aspects of the SDGs or indirect environmental implications but suggest that qualitative research can complement the quantitative analysis.

Holistic yield modeling, top-down loss analysis, and efficiency potential study of thin-film solar modules

A holistic simulation of a photovoltaic system requires multiple physical levels - the optoelectronic behavior of the semiconductor devices, the conduction of the generated current, and the actual operating conditions, which rarely correspond to the standard testing conditions (STC) employed in product qualification. We present a holistic simulation approach for all thin-film photovoltaic module technologies that includes a transfer-matrix method, a drift-diffusion model to account for the p-n junction, and a quasi-three-dimensional finite-element Poisson solver to consider electrical transport. The evolved digital model enables bidirectional calculation from material parameters to non-STC energy yield and vice versa, as well as accurate predictions of module behavior, time-dependent top-down loss analyses and bottom-up sensitivity analyses. Simple input data like current-voltage curves and material parameters of semiconducting and transport layers enables fitting of otherwise less-defined values. The simulation is valuable for effective optimizations, but also for revealing values for difficult-to-measure parameters.

Ultrasonic guided waves interaction with cracks in the front glass of thin-film solar photovoltaic module

Ultrasonic guided waves interaction with cracks in the front glass of thin-film solar photovoltaic module

A Comprehensive Review on Current Performance, Challenges and Progress in Thin-Film Solar Cells

Due to the recent surge in silicon demand for solar modules, thin-film photovoltaic (PV) modules have a potential to penetrate the market in significant numbers. As an alternate candidate, thin film technologies in PVs have the ability to achieve better performance. The competing thin-film PV technologies have the flexibility to adapt to any sort of curvature compared to rigid solar cells (SCs). Due to the peculiar characteristics of newer solar materials, stability issues, reflection losses, advancements in electrode materials and dopant materials with a photoactive layer are current challenges driving the industrial-academic voyage of development of solar materials for the betterment of Photo-conversion Efficiency (PCE). Based on the photoactive materials used over time, SC evolution was broadly classified into first, second and third generation SCs. In this review, the basic working mechanisms, various materials used, drawbacks and stability issues of different SCs are discussed extensively. Thin film SCs tend to absorb certain elastic deformations due to their flexible nature and to a certain extent. According to the NREL efficiency chart, multi-junctional SCs exhibit enhanced efficiency as compared to the other SCs. Among the third-generation SCs, the perovskite/Si tandem architecture shows a maximum efficiency of approximately 29%. Thin film flexible SCs find application in various sectors such as automobile, defense and/or energy storage devices

Impact of Shunt Resistance on the Performance of Curved Thin-Film Photovoltaic Modules With Series-Connected Solar Cells

Curved photovoltaics (PV) is gaining widespread application in modern energy-efficient infrastructure, wearable electronics, and vehicles. Due to the different orientations of the solar cells in curved PV modules, current mismatch between solar cells is more prevalent in curved PV than conventional flat PV. In this article, we investigated the effect of shunt resistances, which can mitigate current mismatches in series-connected solar cells, on the performance of curved thin-film PV modules. A flexible 85 × 80 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> Cu(In,Ga)Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mini-module composed of 17 series-connected solar cells on a curved surface was characterized experimentally and theoretically. We found that the short-circuit current of the curved PV module is affected by all the solar cells connected in series and is not simply determined by the current-limiting solar cell. The current-voltage characteristics of a curved PV module are well described by a simple model that includes low shunt resistance. The power generated from normal irradiance decreases with shunt resistance; however, the power for tilted illumination is higher than that of a module without shunt resistance. This indicates that the low shunt resistance can suppress the power loss due to current mismatch. In addition, curved PV modules cause self-shading under highly tilted illumination but curved PV modules with low shunt resistances provide power even when some solar cells are not illuminated. Furthermore, sudden current mismatches in solar cells, which generate detrimentally high reverse biases can be eliminated by the shunt resistance. This confirms the protective effect of the shunt resistance to enhance the durability of curved PV modules.

Physics-based electrical modelling of CIGS thin-film photovoltaic modules for system-level energy yield simulations

Copper indium gallium selenide (CIGS) is a commercialized, high-efficiency thin-film photovoltaic (PV) technology. The state-of-the-art energy yield models for this technology have a significant normalized root mean square error (nRMSE) on power estimation: De Soto model—26.7%; PVsyst model—12%. In this work, we propose a physics-based electrical model for CIGS technology which can be used for system-level energy yield simulations by people across the PV value chain. The model was developed by considering models of significant electrical current pathways from literature and adapting it for the system-level simulation. We improved it further by incorporating temperature and irradiance dependence of parameters through characterisation at various operating conditions. We also devised a module level, non-destructive characterization strategy based on readily available measurement equipment to obtain the model parameters. The model was validated using the measurements from multiple commercial modules and has a significantly lower power estimation nRMSE of 1.2%.

Electrical parameters behaviour evaluation of Copper Indium Gallium Diselenide thin-film photovoltaic modules

ABSTRACT This paper aims to study the metastability as well as the degradation of Copper Indium Gallium Diselenide (CIGS) thin-film photovoltaic modules. Potential-induced degradation (PID) test has been carried out on a CIGS thin-film module inside a climatic chamber with a high temperature (85°C), and relative humidity (85%). A negative voltage of −1000 V was applied to the active cell circuit with different configurations. Results showed that the GIGS thin-film module experienced drastically degradation, mostly for front and back contact configurations because of the large area of applying the negative voltage. The I-V curve showed losses in electrical parameters of the degraded module mainly in the maximum power and the fill factor (FF). Different changes in performance have been observed in the first hour of the test confirming that the tested modules exhibited metastability with the light soaking (LS) effect by improvement in open-circuit voltage (Voc) and FF. A recovery process has been performed on degraded modules by applying positive voltage of +1000 V, the losses in electrical parameters have been partially recovered to the initial value, this process confirms the effect of a high voltage on modules in PV system.

Development of a P1-filling process to increase the cell performance in the copper indium gallium Selenide photovoltaics by implementation of the inkjet technology

In this paper, the suitability of integrating a digital manufacturing tool i.e. inkjet technology is exemplified to increase the electrical performance of thin-film based Copper Indium Gallium Selenide (CIGS) photovoltaic (PV) modules. Typically, the series connection within the PV module is established conventionally by three adjacent scribing lines at different deposition stages (patterning P1, P2 and P3). The total width of these three scribes is typically in the order of several 100's of microns and is electrically inactive, so these regions are lost areas for current generation (up to 5% “dead area”). To reduce the line width of the first scribe (P1) without compromising on the electrical parameters, we have concentrated on accurately filling of the interconnect P1-trenches with insulating material using inkjet technology, as initial step to realize the concept for dead area reduction by developing a P1-filling process (< 80 μm printed filling width) for laser structured/patterned trenches of ~50 μm width. With the right combination of carefully selected material interface, inkjet printhead, deposition settings, pattern digitalization & other parameters, we are able to develop an industry relevant micro-filling process. And, show an increase in the performance of PV cells, as compared to the reference modules. The results lay the foundation for direct up-scaling to industrial-size substrate areas and open up the possibility to realize all kinds of advanced interconnect schemes for the next generation thin-film CIGS PV modules. • Digital manufacturing of P1-filling for the thin-film photovoltaics in conjunction with laser process. • Approach towards reduction of dead-area in photovoltaics. • Inkjet printing of functional material within μm range channels/trench (< 80 μm). • Increase in photovoltaic performance (fill factor & module efficiency). • P1-filling process developed under ambient condition, without any inert atmosphere.

Optimal identification of model parameters for PVs using equilibrium, coot bird and artificial ecosystem optimisation algorithms

Realising an accurate estimation of model parameters for solar cells and the Photovoltaic modules has serious importance for enhancing the performance of their control systems. Three neoteric metaheuristic methods of Artificial Ecosystem-based optimisation, Coot Bird-based optimisation, and Equilibrium optimiser have been applied and evaluated concerning the accurate estimation of various Photovoltaic models. The validation of the applied methods has occurred for valuing the model parameters of R.T.C. France solar cell, and Thin-film ST40 Photovoltaic module. The objective function has been formulated as the Root Mean Square Error between the actual and estimated data. Matlab/Simulink has been used for the verification of the optimisation methods. The outcomes demonstrate that: (1) The three optimisation algorithms can resolve the problem of the Photovoltaic parameter estimation; (2) There are small distinctions between the three algorithms concerning their best value of the impartial function; this distinction between the best and worst algorithm is 10–9 for R.T.C. France solar cell for SDM; (3) The best algorithm considering the best value of the objective function is Artificial Ecosystem-based optimisation for R.T.C. France solar cell; (4) Statistical results prove that the three algorithms have tracking efficiencies of 100%, 99.999%, and 98.285% for Artificial Ecosystem-based optimisation, Coot Bird-based optimisation, and Equilibrium optimiser, respectively, based on 10 individual runs for R.T.C. France solar cell for SDM. Moreover, the simulation results show that the I/V curves obtained employing Artificial Ecosystem-based optimisation, Coot Bird-based optimisation, and Equilibrium optimiser techniques were also matched with the corresponding datasheet curves with the Artificial Ecosystem-based optimisation and Coot Bird-based optimisation's predominance in standings the convergence speed, tracking efficiency, statistical indices, and solution accuracy.

New model to study the outdoor degradation of thin–film photovoltaic modules

The performance of four thin-film photovoltaic modules is analyzed after an initial stabilization period and a subsequent outdoor exposition. The seasonal variations and the degradation rates of a single-junction hydrogenated amorphous silicon (a-Si:H) module, a tandem amorphous microcrystalline Silicon (a-Si/μc-Si) module, a heterostructure cadmium sulfide-cadmium telluride (CdS/CdTe) module and a copper indium gallium selenide (CIGS) are examined and correlated to spectral changes. The I–V curves have been measured every 5 min; the electrical parameters and parasitic resistances have been identified. By exploiting a number of experimental measurements acquired within a narrow interval of irradiance and cell temperature, a novel mathematical model has been developed and fitted: it considers a stationary seasonal variation component and a linear long-term degradation component. The results show annual power degradation rates of 4.0% for the a-Si:H module, 3.4% for the a-Si/μc-Si and 3.5% for the CdS/CdTe, whereas for the CIGS module the annual degradation is not significant, i.e. 0.2%.

Quick Diagnostic Tool for Thin-Film Photovoltaic Power Plants Utilizing Dark Current Measurement

There exist many photovoltaic (PV) power plants which are based on thin-film technology. Unlike PV power plant with crystalline silicon technology, the diagnostic possibilities of thin-film PV modules are limited due to seasonal effects and problematic utilization of thermography. The main problem of degradation of these PV plants is the area degradation which affects even PV power plants with transformer inverters. Although there exist measurement methods based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I–V</i> curve measurement, these methods require specific climatic conditions (clear sky, sufficient irradiance) and time. Here, we present the novel approach to diagnose thin-film modules affected with degradation which provides quick results with low-cost equipment.

Copper iodide nanoparticles as a hole transport layer to CdTe photovoltaics: 5.5 % efficient back-illuminated bifacial CdTe solar cells

We report the role of copper iodide (CuI) nanoparticles (NPs) as a hole transport layer (HTL) in cadmium sulfide/cadmium telluride (CdS/CdTe) photovoltaics. These CuI NPs were prepared using solution processing at room temperature and used to fabricate monofacial and bifacial CdTe solar cells with different back contacts. Using CuI/Au as the back contact, the device efficiency reached to 14.8% with outstanding fill factor (FF) of 79.2%. Replacing the gold (Au) electrode with sputtered transparent indium tin oxide (ITO), a CuI/ITO back contact yielded photoconversion efficiencies (PCEs) of 11.6% and 5.5% under front and back illumination respectively. Bifacial devices (CdTe/ITO) without the CuI NP HTL have an efficiency of 7.0% and 1.0% for front and back illumination, respectively. For CuI/ITO, a current collection of 12.0 mAcm−2 was observed upon back illumination which significantly improved over an ITO-only back contact (5.0 mAcm−2). The PCE obtained from back illumination was enhanced when using CuI NPs as the HTL due to the reduced back barrier height, and improved back interface as determined by temperature dependent current vs. voltage characteristics and impedance spectroscopy analysis. The improvement in device performance of the bifacial configuration is a significant step forward toward realizing thin film photovoltaic modules which harvest energy incident on the rear of the module.

Performance Assessment of Hetero-Junction Intrinsic Thin Film HIT Photovoltaic Module Using Machine Learning Methods

A solar cell built of ultra-thin amorphous silicon and high-quality mono-crystalline silicon is known as a hetero-junction intrinsic thin film. It has a pyramid surface on the front that increases sunlight absorption. The operating environment has a significant impact on the performance of hetero-junction intrinsic thin-film photovoltaic modules with real I–V (current-voltage) characteristics. Changes in the environment have a significant impact on solar irradiation. Clouds also have a significant impact on the solar irradiation that a PV cell receives. In this project, we will use the Random Forest Regression machine learning algorithm to investigate the effects of sudden changes in environmental conditions on power output and module temperature of an HIT (Heterojunction with Intrinsic Thin Layer) module, where irradiance, temperature, and module efficiency parameters are taken into account when designing modules. The algorithm’s output will be studied to gain a better understanding of performance variations as well as the behavior of the power output and module temperature when subjected to random influences induced by various environmental variables. The suggested algorithm is not restricted to a certain module technology or geographic location.

Reconfigurable linkage structures and photovoltaics integration

A type of reconfigurable building structures is presented which comprises an arrangement of multilink planar linkages. Interconnections are applied to allow for the individual linkages to move together and the control action to be transferred between them. The linkages constitute the skeleton structure and define the building envelope. The elementary planar linkages include a central sliding member on an elevated midspan structural mechanism. On either side of the slider connects a chain of serially-connected members, the other end of which is pin-connected to the ground. Actuation is directly applied on the sliding member, while all rotational joints are equipped with brakes as required to implement a multistep reconfiguration control method. In each step, a selective application of the brakes appropriately modifies the kinematic structure of the linkage to resemble a dual version of a crank–slider mechanism. This is a 1-DOF system which is favorable from a control perspective. Simulations are employed to demonstrate the concepts. Finally, thin-film photovoltaic modules integrated on the spatial structure highlight potential benefits enabled by reconfigurable buildings with regard to the solar irradiance and energy production. • A reconfigurable building structure has been investigated. • The spatial structure consists of connected multilink planar linkages. • The system reconfiguration is based on the dual effective crank–slider concept. • Actuation is applied on the sliding member on an elevated midspan mechanism. • The study involves a photovoltaics integration in the building envelope.

Compound control strategy for maximum power point tracking with flexible step-up converters for thin film photovoltaic module applications

Compound control strategy for maximum power point tracking with flexible step-up converters for thin film photovoltaic module applications

Influence of Light Irradiation on Potential-Induced Degradation for Thin-Film Si Photovoltaic Modules

Delamination observed for superstrate-type thin-film Si photovoltaic (PV) modules exposed outdoors was reproduced by indoor acceleration test with high-voltage application. Such delamination was observed for the PV modules left in the air after potential-induced degradation (PID) acceleration test and was a kind of PID. The delamination occurred near the interface between glass and transparent conductive oxide. In this study the origins of the delamination for thin-film Si PV modules were analyzed and the influences of light irradiation and humidity were also investigated. The delamination occurred only at the position with voltage application and high concentration of Na was detected at the delamination region. Delamination was also enhanced by high humidity. It also turned out that light irradiation delays both deterioration of PV performances and also the delamination by high-voltage application. However, PID behaviors are almost the same regardless of including UV component. This is much different from crystalline Si case that UV component is required for the PID delay.

Marine predators algorithm for parameters estimation of photovoltaic modules considering various weather conditions

The accurate models of photovoltaic systems are the core of solar energy studies that are describing the system performance and behavior under different operating conditions. The improving of photovoltaic models based on optimizing method is recently the main simulation tool to construct I-V and P–V characteristic curves with the aid of system parameters. These parameters are extracted by using powerful optimal techniques that are building-up from datasheet of manufacturers or experimental data. This paper presents a novel proposed photovoltaic model based on Marine Predators Algorithm to estimate the optimal model parameters of solar cells or modules. Also, it can extract parameters of single diode, double diode and three diode models. Moreover, the Route Mean Square Error value between each model computed parameters and measured results of photovoltaic components are considered as the objective function. R.T.C. France Solar Cell, Photowatt-PWP201 and thin-film photovoltaic modules have been implemented to extract parameters for all three previously mentioned models at different irradiance intensities or temperature degrees. The proposed algorithm results of such cells and modules for each diode model are compared with other research works and manufacturer's results. Moreover, the evaluation of proposed algorithm has been presented considering the complexity analysis and statistical tests. The compared results show that, the accuracy of algorithm results is the best and their I-V and P–V characteristic curves are highly coinciding with manufacturer's curves. Therefore, the results of the proposed algorithm are satisfied with high superiority and better reliability to optimize parameters under different operating conditions.