Photovoltaic Performance Research Articles

Organic Salt-Doped Polymer Alloy: A New Prototype Hole Transporter for High-Photovoltaic-Performance Perovskite Solar Cells.

Hole-transporting layer (HTL) is one of the key components in a regular perovskite solar cell (r-PSC), which has the function of extracting the photon-excited holes from the absorber and then transporting them to the electrode. The most commonly used HTL in r-PSC is LiTFSI and tBP-doped spiro-OMeTAD. The inevitable instability induced by a deliquescent inorganic salt (LiTFSI), the migration of small lithium ions, and the necessary oxidation process in air hinder the commercialization of this technology. In this paper, a new undoped D-A copolymer (P15) is used as a hole-transporting material (HTM) for r-PSC but with moderate photovoltaic performance. Therefore, an organic salt, DPI-TPFB, having a big organic cation and a hydrophobic anion, was used as a dopant to increase the conductivity/hole mobility of P15 while avoiding the instability caused by lithium salt and moisture. Furthermore, an amphiphilic polymer, PDTON (with hole- transporting and perovskite-passivation ability), was added to P15 to form a polymer alloy, (P15 + PDTON), to further enhance the crystallinity and, therefore, the conductivity/hole mobility of P15 via space-confined interaction. As a result, r-PSCs based on DPI-TPFB-doped (P15 + PDTON) HTLs exhibit the highest power conversion efficiency (PCE) of 18.8%, which is higher than those of the cells based on DPI-TPFB-doped P15 (15.08%), DPI-TPFB-doped PDTON (7.37%), and undoped (P15 + PDTON) (15.66%) HTLs. Cells based on DPI-TPFB-doped (P15 + PDTON) HTL also have much better long-term stability than those using LiTFSI and tBP-doped spiro-OMeTAD as an HTL. The studies show that a polymer-compatible organic salt, DPI-TPFB, can be used as a stable dopant to increase the hole mobility of polymeric HTL without sacrificing the stability of the resulting cells, and mixing two ordinary photovoltaic performance polymeric HTLs (such as P15 and PDTON) can form a high- photovoltaic-performance polymer alloy (P15 + PDTON) HTL. Therefore, organic salt-doped polymer alloy can be regarded as a new prototype hole transporter for high-photovoltaic- performance PSCs.

A Platinum Complex‐Based Dimerized Electron Acceptor for Efficient Organic Solar Cells

AbstractMetal–organic complexes have demonstrated excellent performance in organic light‐emitting diodes, yet their potential in organic solar cells (OSCs) remains underexplored. In this study, a novel metal–organic complex, Pt‐Y, which features a platinum core connected to Y‐acceptor arms, for application in OSCs is designed and synthesized. The dimerized Pt‐Y acceptor is prepared through straightforward reactions, with the key precursor linking the platinum metal and Y‐acceptors synthesized through Sonogashira coupling. Steady‐state and transient photoluminescence measurements revealed that Pt‐Y exhibits distinct singlet and triplet states with microsecond lifetimes—significantly longer than the nanosecond lifetimes of Y‐acceptors without the metal. Incorporating Pt‐Y as a third component in ternary OSCs has resulted in a remarkable efficiency of 19.2%. Further morphological analysis and transient absorption measurements indicate that the dimerized Pt‐Y displays excellent miscibility with the Y‐acceptor, leading to minimal phase separation and the formation of fibrillar structures. These structures enhance charge separation and transport while reducing charge recombination. This work presents a facile approach to developing metal–organic complexes with exceptional photovoltaic performance in OSCs.

Experimental evaluation of water cooling effects on photovoltaic module performance in a hot climate

Experimental evaluation of water cooling effects on photovoltaic module performance in a hot climate

Design High-Performance Stretchable Light-Harvesting Polymers for Organic Solar Cells via Synergistic Effect of Flexible Alkyl Segment and Hydrogen Bond.

Stretchable organic solar cells (SOSCs) have great application prospects to serve as energy supply systems, which can be fully incorporated with wearable electronic devices to achieve truly integrated systems that are fully stretchable and wearable. However, the stretchable polymer light-harvesting active layer has not been successfully developed, which limits the development of stretchable organic solar cells. In this regard, a series of stretchable light-harvesting donor and acceptor polymers are designed and synthesized by introducing amide units with flexible alkyl segments and hydrogen bonds as the third component into the PM6 and PY-IT based conjugated polymer backbones. Hydrogen bonds and flexible alkyl segments can dissipate tensile stress for high stretchability. In addition, hydrogen bonds can reduce the impact of flexible alkyl segments on intermolecular stacking, thus maintaining good photovoltaic performance. The obtained results suggest that the incorporation of amide units (5 mol% content) into the donor polymer can efficiently improve the stretchability without compromising the photovoltaic performance. This study provides an understanding of the impact of amide units on properties, offering another entry to the molecular design guidelines for high-performance stretchable light-harvesting polymers, developing high-performance stretchable organic solar cells, and further promoting the development of wearable electronic devices.

Improving photovoltaic water pumping system performance with ANN-based direct torque control using real-time simulation

Photovoltaic Water Pumping Systems (PVWPS) have become increasingly important as a renewable energy solution in rural areas, providing energy independence, cost savings, and environmental friendliness. This system has two main controllers. The first controller is employed to maximize power extraction from the PV array by controlling the duty ratio of the DC-DC boost converter. The second controller is responsible for regulating the operation of the induction motor through the switching pulses of the Voltage Source Inverter (VSI). These two controllers play an essential role in the system, which increases efficiency and performance. Therefore, the innovative aspect of this work consists of introducing Artificial Neural Networks (ANNs) based on each PVWPS controller. On the one hand, ANN-based MPPT is implemented to ensure optimal performance of the PV array under varying irradiation levels. On the other hand, to overcome the defects and problems caused by Direct Torque Control (DTC), such as flux and torque ripples, high switching frequency, and challenges at low speeds, an ANN-based DTC is proposed in which each of the hysteresis comparators, switching table, and speed controller in the DTC are replaced by ANN controllers. The PVWPS based on the proposed controls is thoroughly modeled and simulated using MATLAB/Simulink software and validated using dSPACE DS1104 Board. The results demonstrate significant improvements, including a 75.51% reduction in flux ripples, a 77.5% reduction in torque ripples, a 44.79% improvement in response time, and an increase in the water quantity. Furthermore, the Real-Time simulation and visualization obtained are consistent with the simulation outcomes.

Performance assessment of solar PV panels under varying environmental conditions: a laboratory and field-based approach for sustainable energy in mining operations.

This study provides a novel and comprehensive assessment of solar photovoltaic (PV) panel performance under varying environmental conditions, integrating laboratory experiments with real-world field studies to address challenges specific to mining operations. The research uniquely explores the combined effects of shading, temperature, humidity, dust deposition, and tilt angle, delivering actionable insights for optimizing PV systems in harsh conditions. Laboratory experiments demonstrated that a parallel configuration significantly minimizes power losses under partial shading, while a rise in temperature from 35 to 75°C resulted in a notable 21.34% and 29.12% power output reduction for monocrystalline and polycrystalline panels, respectively. Furthermore, increased humidity (65.40 to 98.20%) caused a 35.82% decline in power output due to scattering effects. Field studies conducted in a surface mining environment revealed that dust accumulation led to a substantial 43.18% drop in maximum power output after 5days, emphasizing the importance of regular cleaning. Optimal energy capture was achieved at a 15° tilt angle, aligning with the site's latitude. These findings underscore the novelty of using combined experimental approaches and field validation to improve PV performance in mining operations. Practical recommendations, including parallel configurations to mitigate shading losses, temperature regulation strategies, and frequent cleaning protocols, are proposed to enhance the sustainability and efficiency of renewable energy systems in challenging environments.

Integration of electrocoagulation and solar energy for sustainable wastewater treatment: a thermodynamic and life cycle assessment study.

This study presents an innovative approach to sustainable wastewater treatment by integrating electrocoagulation (EC) with solar energy and biogas. The research evaluates the performance of an EC reactor in terms of chemical oxygen demand (COD) removal efficiency under varying current densities, demonstrating enhanced COD removal rates with increased current densities, achieving up to 95.3% at 1500 A/m2. Life cycle assessment (LCA) is employed to compare the environmental impacts of different energy sources for powering the EC system. The findings indicate that biogas derived from domestic waste offers a lower environmental impact compared to natural gas, coal, hydro, solar, and wind. The study further explores the potential of solar energy in Turkey, particularly in Istanbul, where high solar radiation could be harnessed. However, the efficiency of photovoltaic (PV) panels is affected by temperature, with an observed efficiency decrease of approximately 0.5% per degree Celsius increase in temperature. Effective cooling strategies are thus essential for optimizing PV performance. The integration of EC with solar energy, powered by biogas, not only enhances wastewater treatment efficiency but also contributes to reduced greenhouse gas emissions and energy costs. This combined approach presents a viable solution for both domestic and industrial wastewater treatment, especially in remote or off-grid areas.

Pulsed Laser Deposition of Halide Perovskites with over 10-Fold Enhanced Deposition Rates.

The potential of the vapor-phase deposition of metal halide perovskites (MHPs) for solar cells remains largely untapped, particularly in achieving rapid deposition rates. In this study, we employ in situ photoluminescence (PL) to monitor the growth dynamics of MHPs deposited via pulsed laser deposition (PLD), with rates ranging from 6 to 80 nm/min. Remarkably, the PL intensity evolution remains consistent across both low- and high-deposition rates, indicating that increased deposition rates do not significantly alter the fundamental mechanisms driving MHP formation via PLD. However, microstructural analysis and time-resolved microwave conductivity (TRMC) measurements reveal that increasing deposition rates lead to randomly oriented films on contact layers and reduced charge mobility compared with films grown at lower deposition rates. These findings emphasize the critical role of controlling initial nucleation and the value of in situ PL monitoring in optimizing the vapor-phase deposition of MHPs for enhanced photovoltaic performance at high deposition rates.

Exploring the impact of substituents on the photophysical properties of boron dipyrromethene dyes for enhanced photovoltaic performance

Abstract Boron dipyrromethene (BODIPY) dyes are known for their strong fluorescence and excellent photostability, making them vital for various photoelectric applications. This study explores how different substituents affect the photophysical properties of BODIPY dyes to improve their performance in dye-sensitized solar cells (DSSCs). We examine six distinct BODIPY dye structures with unique electron-withdrawing (NO2, CHO, Br) and electron-donating (OCH3, NPh2) substituents, along with a hydrogen-substituted variant, and report key photovoltaic parameters, including open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and energy conversion efficiency (Ω). Using density functional theory (DFT) and time-dependent DFT (TD-DFT), we analyze the dyes’ light-harvesting efficiency, electron injection efficiency, and overall energy conversion efficiency. Our results indicate that electron-donating groups, especially NPh2 and OCH3, significantly enhance Voc, Jsc, FF, and Ω, leading to improved energy conversion efficiencies. In contrast, while electron-withdrawing substituents increase chemical stability, they typically result in lower photovoltaic performance. This research underscores the importance of strategic substituent selection in optimizing BODIPY dyes for enhanced photoelectric performance, offering valuable insights for designing efficient photovoltaic materials.

Coherent spin mixing at charge transfer states for spin polaron pair dissociation and energy loss in organic bulk heterojunction solar cells

Balancing the high photocurrent production and the nonradiative recombination suppression is of practical importance to design high-performance organic bulk heterojunction (BHJ) solar cells. Most efforts in this field have been directed towards the understanding of the electronic charge and photogenerated exciton related optoelectronic and transient processes. Little is known about the spin polaron pairs (PPs) dependent dissociation and nonradiative decay at charge transfer states (CTS), where the coherent spin mixing plays a key role. In this work, we combine magneto-photocurrent (MPC) and coherent spin mixing analyses for the IT- and Y-series, i.e., prototypical nonfullerene acceptors (NFA), based organic BHJ systems. We find that increasing polaron pair dissociation rates at singlet charge transfer states (CTS)S give rise to the photocurrent generation. Within the same systems, strong internal fields that include the hyperfine (HF) fields, spin-orbit coupling (SOC), and Δg value may promote the intersystem crossing (ISC) and the polaron back transfer (PBT), leading to the energy loss. By exploring the impact of the coherent spin mixing on the molecular functionality, our study opens new directions for improving photovoltaic performance of BHJ systems.

An iteratively reweighted robust regression model for PV electrical and thermal performance using actual measurement data

The performance of photovoltaic (PV) modules is inherently dynamic, governed by a complex interplay of meteorological factors such as solar irradiance, temperature, and atmospheric conditions. Accurately and effectively predicting this performance remains a crucial area of research. This study aims to establish the correlation between meteorological parameters and power output as well as cell temperature. For this purpose, a prediction model was developed using iteratively reweighted robust regression to estimate both power output and cell temperature. Robust regression models were developed using real measurement data from the PV system and weather station established at the National Institute of Standards and Technology (NIST). The coefficient of determination (R2) and root mean square error (RMSE) of the proposed model for power output are 0.9870 and 0.0542, respectively. For cell temperature, these values are 0.8443 and 0.2194, respectively. The R2 and RMSE statistics of the proposed models indicate successful performance for the climatic conditions studied. Additionally, a series of experiments were conducted to evaluate the sensitivity of the proposed models to the variation in PV performance across regions. Therefore, the developed model is recommended as a powerful tool for predicting the electrical and thermal performance of PV systems.

Advanced room-temperature cured encapsulant film for crystalline silicon solar modules: enhancing efficiency with luminescent down-shifting, flame retardancy, and UV resistance.

Solar energy sources have garnered significant attention as a renewable energy option. Despite this, the practical power conversion efficiency (PCE) of widely used silicon-based solar cells remains low due to inefficient light utilization. In this study, carbon dots (APCDs) were prepared via a hydrothermal method using ammonium polyphosphate and m-phenylenediamine, then incorporated into a silicone-acrylic emulsion (CAS) to create a luminescent down-shifting (LDS) layer for solar cells. The CAS/APCDs films can be molded at room temperature and exhibit outstanding optical and adhesive properties. Application of CAS/APCDs films on solar cell surfaces effectively enhances photovoltaic performance, increasing current density (JSC) by 3.5% and overall PCE by 5.7%. Additionally, APCDs enhance flame retardancy in CAS films, increasing the limiting oxygen index from 29.3% to 32.0%, while reducing peak heat release and peak CO release by 20.2% and 38.9%, respectively. Moreover, APCDs absorb UV light and convert it into visible light, mitigating CAS film degradation. The aged CAS/1.0APCDs film exhibits superior morphology and mechanical properties compared to aged CAS film, maintaining 68.9% light transmission. Overall, this study introduces the development of room-temperature cured LDS layers with extended lifespan and flame retardant characteristics, offering promising applications in solar energy technology.

Nanostructure engineering for ferroelectric photovoltaics.

Ferroelectric photovoltaics have attracted increasing attention since their discovery in the 1970s, due to their above-bandgap photovoltage and polarized-light-dependent photocurrent. However, their practical applications have been limited by their weak visible light absorption and low photoconductivity. Intrinsic modification of the material, such as bandgap tuning through chemical doping, has proven effective, but usually leads to the degradation of ferroelectricity. Recently, various nanostructures, such as multilayer heterojunctions, nanoparticles, vertically aligned nanocomposites and polar nanoregions, have been developed to enhance photovoltaic performance. These approaches enable the nanoassembly of materials in a lower-dimension manner to optimize the bulk photovoltaic effect whilst effectively preserving or even inducing ferroelectricity. This review highlights the fabrication processes of these emerging ferroelectric nanostructures and evaluates their photovoltaic performance.

Highly Efficient and Stable Flexible Perovskite Solar Cells Enabled by Alkylammonium Acetate Modification with Varied Dipole Moments

AbstractInterface modification with the ability to passivate defects and regulate interface energy level is an important method to maximize the photovoltaic performance of perovskite solar cells (PSCs). Herein, through modifying the interface between perovskite and hole transport layer via different alkylammonium acetate ionic liquid molecules with varied dipole moments, efficient and stable PSCs are achieved. Especially, hexylammonium acetate (HAAc) with high dipole moment can reduce the energy difference between perovskite and hole transport layer to facilitate hole extraction and reduce energy loss. In addition, HAAc has a strong chemical binding ability to both acceptor and donor defects on perovskite surfaces through synergistic passivation of HA+ cation and Ac− anion, thereby reducing defect‐assisted recombination. The combined effects of energy level modulation and defect suppression lead to an overall enhancement in device performance. The best HAAc‐passivated device reaches an efficiency of up to 25.06% and maintains > 97.30% initial efficiency for 1000 h in air with 30 ± 10% humidity. In addition, the flexible perovskite solar cells exhibit excellent mechanical stability, with efficiency remaining above 71% of the initial value after 10 000 bending cycles at a small bending radius of 5 mm.

Can residential energy systems withstand the heat? Quantifying solar photovoltaic and heat pump yields for future New Zealand climate conditions

Abstract We investigate how higher temperatures resulting from climate change impact the energy system. Specifically, we examine the cumulative effects of fluctuating solar photovoltaic (PV) generation performance, heating and cooling demand, and heat pump efficiency on such days.
To achieve this, we used the climate analogue space, which maps a given city’s future climate to an existing one. By employing climate analogues, we can predict the impact of higher temperatures by 2050, transforming Auckland, New Zealand’s climate into one akin to Sydney, Australia. This approach avoids reliance on historical weather data, which many energy system models use. We used this future climate time series as an input to a residential energy system model for Auckland, New Zealand. The residential energy system model simulates solar PV generation output via mapping of experimental data, building thermal characteristics via grey-box resistance-capacitance (RC) modelling, and hourly coefficient of performance (COP) for air source heat pumps (ASHP) via linear regression.
Our findings revealed that a future climate doubles the cooling demand and reduces the heating demand by one-third, with the heat pump demand peak load projected to be 40% higher than current demand. Although solar PV generation experiences a decrease in efficiency of 8%, there is a 40% increase in annual direct usage of ASHP. Despite the high cooling demand, the combined yearly electricity demand for heating and cooling decreased by 6.5% overall, and the system saw a 50% improvement in demand fulfilment. However, the system performance volatility at hotter-than-normal temperatures and the potential for significant energy shortfalls remain concerns. The shift from a predominantly heating to a cooling environment is a critical design condition that should be considered in energy expansion planning and future electrification.
The framework and time series developed in this work can be expanded and applied to other energy system modelling exercises.

Simulation-Based Studies on FAGeI3-Based Lead (Pb2+)-Free Perovskite Solar Cells

In the recent reports, it is clear that lead-free perovskite materials with low band gaps are desirable candidates for photovoltaic cells. In this regard, it was observed that germanium (Ge) is a less toxic lead-free metal that is significant for the preparation of Ge-based perovskite materials. Ge-based perovskite materials, for example, methyl ammonium germanium iodide (MAGeI3), cesium germanium iodide (CsGeI3), and/or formamidinium germanium iodide (FAGeI3) may be the suitable absorber materials and alternatives towards the fabrication of lead-free photovoltaic cells. In the past few years, few attempts were made to develop FAGeI3-based perovskite solar cells, but their photovoltaic performance is still under limitations. This is indicating that some significant and effective strategies should be designed and developed for the construction of Ge-based perovskite solar cells. It is believed that optimization of layer thickness, device structure, and selection of a suitable electron transport layer (ETL) may improve the photovoltaic performance of FAGeI3-based perovskite solar cells. Solar cell capacitance simulation, i.e., SCAPS is one of the promising software programs that can provide significant theoretical findings for the development of FAGeI3-based perovskite solar cells. The simulation studies via SCAPS may benefit researchers to save their energy and high cost for the optimization process in the laboratories. In this research article, SCAPS was adopted as a simulation tool for the theoretical investigations of FAGeI3-based perovskite solar cells. The simulation studies exhibited the excellent efficiency of 15.62% via SCAPS. This study proposed the optimized device structure of FTO/TiO2/FAGeI3/PTAA/Au with enhanced photovoltaic performance.

Coupled pyroelectric-photovoltaic effect in 2D ferroelectric α-In2Se3

Pyroelectric and photovoltaic effects are vital in cutting-edge broadband sensors and solar energy harvesting. Recent advances revealed great potential of the bulk photovoltaic effect in two-dimensional (2D) materials to surpass the Shockley-Queiseer limit. Moreover, the atomic thickness, high thermal conductivity and room-temperature ferroelectricity endow 2D ferroelectrics with a superior pyroelectric response. Herein, we combined direct pyroelectric-photovoltaic measurements in 2D α-In2Se3. The results reveal a gigantic pyroelectric coefficient of ∼30.7 mC/m2K and a figure of merit of ∼135.9 m2/C. Moreover, a coupled pyroelectric-photovoltaic effect was demonstrated, where the pyroelectric current follows the temperature derivative, while the short-circuit current follows temperature. Finally, we utilized the intercoupled ferroelectricity of In2Se3 to realize a non-volatile, self-powered photovoltaic memory operation, demonstrating stable short-circuit current switching with 103 ON-OFF ratio. The coupled pyroelectric-photovoltaic effect, along with reconfigurable photocurrent, pave the way for a novel integrated thermal and optical response, in-memory logic and energy harvesting.

Multi-Criteria Optimal Operation Strategy for Photovoltaic Systems in Large-Scale Logistics Parks Concerning Climate Impact

Solar power is widely regarded as one of the most promising renewable resources for generating electricity and reducing building energy consumption. Logistics parks, with their low-rise buildings and extensive rooftop areas, offer significant advantages for solar energy utilization via rooftop photovoltaics (PVs). However, limited research has been conducted on the proper operational principles and optimized control strategies for the PV systems of logistics parks, particularly regarding the mismatch between power generation and the loads of various building types under varying climatic conditions. This study proposes four optimal PV operation strategies for large-scale logistics parks across diverse climatic regions, developed using a multi-criteria optimization approach. The strategies optimize the azimuth and tilt angles of PV panels under four adjustment frequencies: annual, semi-annual, seasonal, and monthly. The investigated strategies are validated in a 5500 m2 logistics park, comprising refrigerated storage, warehouses, sorting centers, and other facilities. The results indicate that the proposed strategies outperform conventional fixed-angle approaches, with the monthly adjustment strategy delivering the best performance. Economic costs are reduced by 9.26–17.02%, while self-sufficiency can be improved by 2.00–7.08%. Cold regions with high solar radiation show particularly significant benefits, with self-consumption increasing by 82.44–359.04%. This study provides valuable insights and practical guidelines for optimizing PV system operations in logistics parks, offering enhanced energy efficiency and cost-effectiveness.

Thiophene Copolymer Donors Containing Ester-Substituted Thiazole for Organic Solar Cells.

Organic solar cells have seen significant progress in the past 2 decades with power conversion efficiencies (PCEs) exceeding 20% but mostly based on high-cost photovoltaic materials. Polythiophenes (PTs) without a fused-ring structure are good candidates as low-cost donor materials, deserving more attention for studying. In this work, ester-substituted thiazole (E-Tz) was explored as the electron-withdrawing unit to design PTs, and further optimization on the fluorinated/nonfluorinated donor segment contents via copolymerization strategy was simultaneously performed, yielding polymer donors of PTETz-100F, PTETz-80F, and PTETz-0F. Suitable temperature-dependent aggregation for reasonable phase separation and compact molecular packing for improved charge transport were achieved in the PTETz-80F-based system, resulting in higher exciton dissociation probability and charge collection probability. Thereby, devices based on PTETz-80F:L8-BO exhibited the best photovoltaic performance with a PCE of 12.69%. In addition, the synthetic complexity of PTETz-XF polymers is 46.05%, which is significantly lower than those of other representative high-performance polymer donors. This work demonstrates the feasibility of designing PTs with an E-Tz unit and the effectiveness of the copolymerization strategy on material property and device performance optimization.

Parametric Optimization of Concentrated Photovoltaic-Phase Change Material as a Thermal Energy Source for Buildings

A concentrated photovoltaic system is evaluated as a thermal energy source employing phase change material to meet the domestic water heating demand. A paraffin wax-based phase change material is selected with a 58 °C melting point to store enough thermal energy to match the hot water demand in the buildings. The energy performance of the concentrated photovoltaics containing phase change materials is compared to that of the reference to determine the increased energy outputs due to the heat removal by the material. The concentrated photovoltaics-phase change material achieved 30% higher energy output compared to the reference concentrated photovoltaic, thus providing a strong justification for the improved thermal management design. An enthalpy-based thermal model is developed to compare the experimental results with model predictions, confirming a reasonable agreement between the results. The model is used determine the optimum melting point and container size for different phase change materials under different radiation concentrations for the hot climate of the United Arab Emirates.