Promising Photovoltaic Technology Research Articles

Dual-interface passivation to improve the efficiency and stability of inverted flexible perovskite solar cells by in-situ constructing 2D/3D/2D perovskite double heterojunctions

Perovskite solar cells (PSCs) have demonstrated considerable potential as a promising photovoltaic technology. Nevertheless, the continued advancement is impeded by the presence of interfacial defects, which give rise to nonradiative recombination and ion migration. In this work, we demonstrate a simple and effective method to in-situ construct 2D/3D/2D perovskite double heterojunctions for effective passivation of defects and mitigation of ion migration in 3D perovskites. As a result, the inverted double-heterojunction PSCs exhibited a high power conversion efficiency (PCE) of 24.08 % with a low VOC loss of 0.37 V due to the minimal nonradiative recombination by dual-interface passivation. The stability of double-heterojunction devices has been significantly improved, maintaining 92 % of the initial value after 3000 h of storage under indoor light in a N2 atmosphere. Especially, the 2D/3D/2D perovskite double heterojunctions are applicable to flexible PSCs (FPSCs) to enhance both PCE and mechanical stability by effective residual stress release. Consequently, the FPSCs demonstrated a PCE of 21.58 % while retaining 86 % of the initial PCE even after undergoing a multi-cycle bending test for 10,000 cycles.

Biomass-Derived Materials in Perovskite Solar Cells: Recent Progress and Future Prospects.

As a promising photovoltaic (PV) technology, perovskite solar cells (PSCs) have made significant progress in attaining high PCE, while challenges remain regarding stability and low cost. Conventional PSCs using noble metals (e.g., Au and Ag) as back electrodes and transparent conducting oxides as front electrodes contribute significantly to their high costs. PSCs comprising biomass-derived materials, such as biocarbon as back electrodes and flexible and transparent cellulosic substrates as front electrodes, offer a promising solution to address these issues. These approaches have the potential to simultaneously improve stability and decrease manufacturing costs, making PSCs closer to commercialization. This review article furnishes a comprehensive overview of recent developments in biocarbon-based perovskite solar cells (C-PSCs), focusing on various biomass-derived biocarbon materials utilized as back electrodes in different C-PSCs device structures. This article also compiles the advancement of flexible and transparent cellulosic substrate-based PSCs by highlighting the fundamentals of PSC and C-PSC architectures, the basics of biomass, and the synthesis of biocarbon. Finally, this review discusses the current challenges and future research directions for optimizing biocarbon materials and cellulosic substrates in PSC technology.

Sublimation and Recrystallization of CsPbBr3 Constructing a Perovskite-Carbon Interface to Facilitate Hole Transfer in Printable All-Inorganic Perovskite Solar Cells.

All-inorganic perovskite solar cells (APSCs) are a promising photovoltaic technology due to their unique physical and optical properties. For printable all-inorganic perovskite solar cells, the key factors limiting their photoelectric conversion performance are the crystallization of perovskite and the hole collection capability at the perovskite-carbon interface. In this study, leveraging the high-temperature tolerance of CsPbBr3 perovskite, the sublimation and recrystallization processes were controlled, significantly improving the crystalline quality of the perovskite and suppressing the generation of the nonphotovoltaic CsPb2Br5 phase. Furthermore, a continuous distribution of high-quality CsPbBr3 crystals was achieved at the interface between the carbon electrode and the zirconium oxide layer, ensuring efficient collection of photogenerated holes. The photoelectric conversion efficiency of the printable mesoscopic all-inorganic perovskite solar cell was increased from 5.04 to 8.34% (with a record value of 10.04%) and achieved an ultrahigh open-circuit voltage of 1.54 V due to the significant improvement in the crystal quality of CsPbBr3. This study proposes a novel strategy to enhance the photovoltaic conversion performance of carbon-based all-inorganic perovskite solar cells by suppressing the presence of nonphotovoltaic phases.

Unraveling the Synergistic Effects of Thiazolidine Co‐Sensitizers in Dye‐Sensitized Solar Cells

ABSTRACTDye‐sensitized solar cells (DSSCs) have garnered significant attention as a promising photovoltaic technology because of their low cost and simplicity. However, the development of efficient organic sensitizers remains a challenge. In this study, we report the synthesis and characterization of two novel organic co‐sensitizers, CD‐1 and TD‐2, based on a thiazolidine core structure and the incorporation of carbazole and triphenylamine donor moieties, respectively. Co‐sensitizers were designed to leverage the strong electron‐donating abilities of these donors to facilitate efficient light‐harvesting and charge‐transfer processes. In‐depth analyses of the spectroscopic and electrochemical properties provided insights into the characteristics of TD‐2 compared with those of CD‐1. TD‐2 displayed a wider range of absorption wavelengths, a narrower energy gap (2.19 eV), and a higher energy level for its (HOMO) than that of CD‐1. These distinctions are attributed to the enhanced capacity of TD‐2 to donate electrons and the elongated π‐conjugation of the triphenylamine component. Upon sensitization, the TD‐2 scored efficiency reached 5.10% and co‐sensitized with N719 dye achieved the highest efficiency, reaching 7.95%. Both sensitizers increased the efficiency of N719 by co‐sensitization (TD‐2 + N719), with an efficiency higher than 15% compared with N719.

Solid Additive Engineering for Next-generation Organic Photovoltaics.

Solution-processed bulk heterojunction (BHJ) organic solar cells (OSCs) have emerged as a promising next-generation photovoltaic technology. In this emerging field, there is a growing trend of employing solid additives (SAs) to fine-tune the BHJ morphology and unlock the full potential of OSCs. SA engineering offers several significant benefits for commercialization, including the ability to i) control film-forming kinetics to expedite high-throughput fabrication, ii) leverage weak noncovalent interactions between SA and BHJ materials to enhance the efficiency and stability of OSCs, and iii) simplify procedures to facilitate cost-effective production and scaling-up. These features make SA engineering a key catalyst for accelerating the development of OSCs. Recent breakthroughs have shown that SA engineering can achieve an efficiency of 19.67% in single-junction OSCs, demonstrating its effectiveness in promoting the commercialization of organic photovoltaic devices. This review provides a comprehensive overview of significant breakthroughs and pivotal contributions of emerging SAs, focusing on their roles in governing film-forming dynamics, stabilizing phase separation, and addressing other crucial aspects. The rationale and design rules for SAs in highly efficient and stable OSCs are also discussed. Finally, the remaining challenges are summarized, and perspectives on future advances in SA engineering are offered.

Progress of Hole-Transport Layers in Mixed Sn-Pb Perovskite Solar Cells.

Hybrid organic-inorganic lead halide perovskite solar cells (PSCs) have rapidly emerged as a promising photovoltaic technology, with record efficiencies surpassing 26%, approaching the theoretical Shockley-Queisser limit. The advent of all-perovskite tandem solar cells (APTSCs), integrating Pb-based wide-bandgap (WBG) with mixed Sn-Pb narrow-bandgap (NBG) perovskites, presents a compelling pathway to surpass this limit. Despite recent innovations in hole transport layers (HTLs) that have significantly improved the efficiency and stability of lead-based PSCs, an effective HTL tailored for Sn-Pb NBG PSCs remains an unmet need. This review highlights the essential role of HTLs in enhancing the performance of Sn-Pb PSCs, focusing on their ability to mitigate non-radiative recombination and optimize the buried interface, thereby improving film quality. The distinct attributes of Sn-Pb perovskites, such as their lower energy levels and accelerated crystallization rates, necessitate HTLs with specialized properties. In this study, the latest advancements in HTLs are systematically examined for Sn-Pb PSCs, encompassing organic, self-assembled monolayer (SAM), inorganic materials, and HTL-free designs. The review critically assesses the inherent limitations of each HTL category, and finally proposes strategies to surmount these obstacles to reach higher device performance.

Optimization of laser patterning process for eco-friendly tin-halide perovskite solar module – with a nanosecond green laser

The tin-based perovskite solar cells are promising future eco-friendly photovoltaic technology with increasing efficiency, which relies on fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) as a transparent conducting oxide (TCO) for front contact. In the monolithic module fabrication process interconnections are executed by a series of three scribes with two different lasers 1064 nm and 532 nm. This study aims to simplify the interconnection process in tin-based perovskite solar modules by using a single visible laser source to perform all three scribes. The study uses an inverted device structure of Glass/TCO/ Poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate (PEDOT: PSS)/Formamidinium-tin-iodide (FASnI3)/C60/Bathocuproine (BCP)/Ag and a 532 nm nanosecond pulsed laser source to pattern the ITO and FTO (P1 scribe), the PEDOT: PSS/FASnI3/C60/BCP stack (P2 scribe), and the PEDOT: PSS/FASnI3/C60/BCP/Ag (P3 scribe). The quality of the P1 scribe is assessed by examining the edges, completeness of film removal, cracking, film delamination, and elemental mapping using a stylus profiler, optical microscope, and energy dispersive x-ray spectroscopy. The P1 scribe is completely removed with line widths of 70 µm and 110 µm of ITO and FTO, respectively, without damage to the glass substrate. The profiles are steep, and the electrical isolation is greater than 40 MΩ. The same 532 nm laser is used for P2 and P3 scribes. The ablation of PEDOT: PSS during P2 and P3 scribe is studied by Raman spectroscopy. The results show that the use of a single 532 nm laser source can simplify the patterning process of monolithic tin-based perovskite solar modules, and potentially reduce production costs.

Multi‐Scale Simulation of Reverse‐Bias Breakdown in All‐Perovskite Tandem Photovoltaic Modules under Partial Shading Conditions

Herein, a multi‐scale simulation approach to quantify the impact of nonuniformities in cell‐level performance on the photovoltaic characteristics of monolithically interconnected large‐area all‐perovskite tandem modules under partial shading conditions is presented, addressing a crucial aspect of the up‐scaling challenge for this promising photovoltaic technology. To this end, current–voltage characteristics of small‐area all‐perovskite tandem solar cells are obtained for dark and illuminated cases from a calibrated optoelectronic device model using drift–diffusion simulation coupled to a quantum transport formalism for the band‐to‐band tunneling underlying the Zener breakdown. These current–voltage curves are computed for varying density of mobile ions and subsequently used as local 1D coupling laws connecting the 2D electrodes in a quasi‐3D large‐area finite‐element simulation approach that then provides the module characteristics under consideration of spatial variation in active area quality related to mobile ion density. The simulation reveals the appearance of localized current hot spots for the case where the shaded cell is strongly reverse biased.

In Situ Growth of MoS2 Onto Co-Based MOF Derivatives Toward High-Efficiency Quantum Dot-Sensitized Solar Cells.

Quantum dot sensitized solar cells (QDSCs) represent a promising third-generation photovoltaic technology, boasting a high theoretical efficiency of 44% and cost efficiency. However, their practical efficiency is constrained by reduced photovoltage (Voc) and fill factor (FF). One primary reason is the inefficient charge transfer and elevated recombination rates at the counter electrode (CE). In this work, a novel CE composed of a titanium mesh loaded with Co,N─C@MoS2 is introduced for the assembly of QDSCs. The incorporation of nanosized MoS2 enhances the density of catalytic sites, while the Co,N─C component ensures high conductivity and provides a substantial active surface area. Additionally, the titanium mesh's 3D structure serves as an effective electrical conduit, facilitating rapid electron transfer from the external circuit to the composite. These improvements in catalytic activity, charge transfer rate, and stability of the CE significantly enhance the photovoltaic performance of QDSCs. The optimized cells achieve a groundbreaking power conversion efficiency (PCE) of 16.39%, accompanied by a short-circuit current density (Jsc) of 27.26mA cm-2, Voc of 0.818V, and FF of 0.735. These results not only offer a new strategy for designing electrodes with high catalytic activity but also underscore the promising application of the Co,N─C@MoS2 composite in enhancing QDSC technology.

Device design of efficient HTL-free all carbon-based perovskite solar cell

Perovskite solar cells (PSCs) are a very promising photovoltaic technology, however, the cost issue of their precious metal back electrodes needs to be addressed. Carbon-electrode-based perovskite solar cells (C-PSCs) have attracted considerable attention for their superior stability, high economic efficiency, and eco-friendliness. However, compared to other types of PSCs, there is still significant potential for improving the power conversion efficiency (PCE) of C-PSCs. Moreover, if the transparent front electrode and transport layer can also be replaced by stable carbon materials to form the all-carbon-based PSCs (AC-PSCs), it will further promote their practical applications. This work proposes four types of C-PSCs (including two AC-PSCs) and conducts simulation with the SCAPS-1D program. For the four structures, the device with FASnI3 absorber layer always has better performance, and the structure of graphene/C60/FASnI3/carbon (Cell 4) attained the highest PCE of 31.62%. The optimal parameters for each layer are also determined through the simulation work. This work will promote the development of all-carbon-based perovskite solar cells.

Crown Ethers with Different Cavity Diameters Inhibit Ion Migration and Passivate Defects toward Efficient and Stable Lead Halide Perovskite Solar Cells.

Organic-inorganic hybrid metal halide perovskite solar cells have been considered as one of the most promising next-generation photovoltaic technologies. Nevertheless, perovskite defects and Li+ ionic migration will seriously affect the power conversion efficiency and stability of the formal device. Herein, we designed two crown ether derivatives (PC12 and PC15) with different cavity diameters, which selectively bind to different metal cations. It is found that PC15 in perovskite precursor solution can actively regulate the nucleation and crystallization processes and passivate the uncoordinated Pb2+ ions, while PC12 at the interface between the perovskite layer and hole-transporting layer can effectively inhibit the migration of Li+ ions and reduce nonradiative recombination losses. Therefore, PC12 and PC15 can act as "lubricant" and defect passivators, as well as inhibitors of ion migration, when they are synergistically applied at the surface and bulk of perovskite layer. Consequently, the optimized device achieved a champion efficiency of 24.8% with significantly improved humidity, thermal, and light stability.

Regulating TiO2 Deposition Using a Single-Anchored Ligand for High-Efficiency Perovskite Solar Cells.

Planar perovskite solar cells (PSCs), as a promising photovoltaic technology, have been extensively studied, with strong expectations for commercialization. Improving the power conversion efficiency (PCE) of PSCs is necessary to accelerate their practical application, in which the electron transport layer (ETL) plays a key part. Herein, a single-anchored ligand of phenylphosphonic acid (PPA) is utilized to regulate the chemical bath deposition of a TiO2 ETL, further improving the PCE of planar PSCs. The PPA possesses a steric benzene ring and a phosphoric acid group, which can inhibit the particle aggregation of the TiO2 film through steric hindrance, leading to optimized interface (ETL/perovskite) contact. In addition, the incorporated PPA can induce the upshift of the Fermi-level of the TiO2 film, which is beneficial for interfacial electron transport. As a consequence, the PSCs with PPA-TiO2 achieve a PCE of 24.83%, which is higher than that (24.21%) of PSCs with TiO2. In addition, the unencapsulated PSCs with PPA-TiO2 also exhibit enhanced stability when stored in ambient conditions.

How to enable highly efficient and large‐area fabrication on specific textures for monolithic perovskite/silicon tandem solar cells?

AbstractPerovskite/silicon tandem solar cells (PVSK/Si TSCs) have emerged as a promising photovoltaic technology toward achieving a high power conversion efficiency (PCE) along with cost‐effective manufacturing. The PCE of PVSK/Si TSCs has skyrocketed to a certified 33.9%, surpassing the theoretical limit of any single‐junction solar cell. This achievement is partially attributed to advancements in surface textures for Si bottom cells. In this regard, we present an overview of the recent developments concerning surface textures of Si in monolithic PVSK/Si TSCs, including planar, pyramid texture, and nanotexture. Following, the prevailing perovskite deposition methods on these textures are thoroughly discussed, and the corresponding challenges are evaluated. Additionally, we provide a summary of the advanced morphological, structural, optical, and electrical characterization techniques being utilized for theses textures. Finally, the prospects for further development of PVSK/Si TSCs are outlined, including designing novel textures with industrial compatibility, developing perovskite deposition methods with scalability, and exploring more pertinent characterization techniques for textured PVSK/Si TSCs.

Positive Effects of Guanidinium Salt Post-Treatment on Multi-Cation Mixed Halide Perovskite Solar Cells.

As one of the most promising photovoltaic technologies, perovskite solar cells (PSCs) exhibit high absorption coefficients, tunable bandgaps, large carrier mobilities, and versatile fabrication techniques. Nevertheless, the commercialization of the technology is hindered by poor material stability, short device lifetimes and the scalability of fabrication techniques. To address these technological drawbacks, various strategies have been explored, with one particularly promising approach involving the formation of a low-dimensional layer on the surface of the three-dimensional perovskite film. In this work, we demonstrate the use of guanidinium tetrafluoroborate, CH6BF4N3, (GATFB) as a post-treatment step to enhance the performance of PSCs. Compared with the control sample, the application of GATFB improves the film surface topology, reduces surface defects, suppresses non-radiative recombination, and optimizes band alignment within the device. These positive effects reduce recombination losses and enhance charge transport in the device, resulting in PSCs with an open-circuit voltage (VOC) of 1.18 V and a power conversion efficiency (PCE) of 19.7%. The results obtained in this work exhibit the potential of integrating low-dimensional structures in PSCs as an effective approach to enhance the overall device performance, providing useful information for further advancement in this rapidly evolving field of photovoltaic technology.

Nitrogen-Blowing Assisted Strategy for Fabricating Large-Area Organic Solar Modules with an Efficiency of 15.6.

Organic solar cells (OSCs) are one of the most promising photovoltaic technologies due to their affordability and adaptability. However, upscaling is a critical issue that hinders the commercialization of OSCs. A significant challenge is the lack of cost-effective and facile techniques to modulate the morphology of the active layers. The slow solvent evaporation leads to an unfavorable phase separation, thus resulting in a low power conversion efficiency (PCE) of organic solar modules. Here, a nitrogen-blowing assisted method is developed to fabricate a large-area organic solar module (active area = 12 cm2) utilizing high-boiling-point solvents, achieving a PCE of 15.6%. The device fabricated with a high-boiling-point solvent produces a more uniform and smoother large-area film, and the assistance of nitrogen-blowing accelerates solvent evaporation, resulting in an optimized morphology with proper phase separation and finer aggregates. Moreover, the device fabricated by the nitrogen-blowing assisted method exhibits improved exciton dissociation, balanced carrier mobility, and reduced charge recombination. This work proposes a universal and cost-effective technique for the fabrication of high-efficiency organic solar modules.

Work Function Tuning of Carbon Electrode to Boost the Charge Extraction in Hole Transport Layer-Free Perovskite Solar Cells.

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF)of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

Improving the performance and stability of inverted perovskite solar cell modules by cathode interface engineering

Perovskite solar cells (PSCs) represent a highly promising photovoltaic technology wherein a low-work function metal cathode is essential for efficient electron collection. The effectiveness of PSCs is significantly enhanced by a well-designed cathode interface layer (CIL). Characterized by their simple structure and impressive modification capabilities, small-molecule CILs hold considerable commercial potential for advancing the performance of PSCs. Herein, we synthesized a conjugated small-molecule CIL, named FY1, for modulating the cathode interface of inverted PSCs to enhance the power conversion efficiency (PCE) and long-term stability. FY1 not only optimized the molecule/metal contact to reduce traps but also uniformly improved the efficiency and speed of extracting photogenerated electrons, facilitating their effective extraction at the cathode interface. FY1 modification reduced the work function of Ag, subsequently lowering the energy barrier for electron transfer from the electron transport layer to the external cathode metal. By employing FY1 as a CIL, a record-high PCE of 23.72 % and a fill factor of 82.3 % were achieved in inverted PSCs. Furthermore, FY1 modification increased the PCE of PSC modules with an active area of 14 cm2 to 21.8 %; after continuous illumination for 850 h, it retained approximately 98.5 % of the initial efficiency. These findings show that FY1 can assist in unlocking the full potential of this emerging photovoltaic technology.

Design and upgrade of mesoporous perovskite solar cells

In recent years, there has been notable progress in the development of perovskite solar cells (PSCs), marked by significant advancements in efficiency, stability, and scalability. Among different device architectures and technical routes, mesoporous perovskite solar cells (MPSCs) based on TiO2/ZrO2/carbon scaffold and screen-printing fabrication process have shown unique advantages for mass production and commercialization due to the low material cost and scalable fabrication process. Through efforts on material optimization, interface engineering, and device design, the power conversion efficiency of MPSCs has steadily increased from the initial 6.64 ​% in 2013 to current 22.22 ​%. Attributing to the screen-printing-based fabrication process, printable mesoscopic PSCs have enabled large-area devices, from mini-modules to modules, and solar panels. In this review, we discuss the development and latest advances of MPSCs, and provide outlooks for further improving the performance of this promising photovoltaic technology.

How can we improve the stability of organic solar cells from materials design to device engineering?

AbstractAmong a promising photovoltaic technology for solar energy conversion, organic solar cells (OSCs) have been paid much attention, of which the power conversion efficiencies (PCEs) have rapidly surpassed over 20%, approaching the threshold for potential applications. However, the device stability of OSCs including storage stability, photostability and thermal stability, remains to be an enormous challenge when faced with practical applications. The major causes of device instability are rooted in the poor inherent properties of light‐harvesting materials, metastable morphology, interfacial reactions and highly sensitive to external stresses. To get rid of these flaws, a comprehensive review is provided about recent strategies and methods for improving the device stability from active layers, interfacial layers, device engineering and encapsulation techniques for high‐performance OSC devices. In the end, prospectives for the next stage development of high‐performance devices with satisfactory long‐term stability are afforded for the solar community.

SUIVI DU POINT DE PUISSANCE MAXIMUM DANS UN SYSTÈME DE POMPAGE SOLAIRE PEROVSKITE AVEC UN MOTEUR À INDUCTION SIX PHASE

In this work, the maximum power point (MPP) of a photovoltaic (PV) array utilized as a source of electricity in standalone mode is tracked using a genetic algorithm (GA) as an optimization tool. The major objective of this work is to implement and regulate a six-phase induction motor (SPIM) powered by a centrifugal pump and fed by a perovskite solar array through a three-phase inverter. Perovskite solar cells are the most promising third-generation photovoltaic technology to replace silicon-based photovoltaic. These cells are made cheaply, at a low temperature, and efficiently. The outcomes are then investigated utilizing a SPIM scaler (v/f) closed-loop control. PID controllers are tuned to keep the motor speed aligned with the reference value. The transformer's six-phase secondary is linked to an LC filter to reduce the voltage and current waveform ripple. A test setup was created and installed to investigate the potential of controlling the SPIM fed via a three-to-six-phase transformer. The findings showed that the area needed for the plates when utilizing perovskite solar cells is just 14 % of what it would be if a silicon-based solar array were used for the identical purpose. Perovskite solar cells' tiny surface area helps to prevent partial shading and lower costs. It was discovered that the suggested method works well for powering SPIM from a three-phase source.