Performance Of Photovoltaic Devices Research Articles

Influence ofF-containing Materialson Perovskite Solar Cells.

Perovskite solar cells (PSCs) are usually modified and passivated to improve their performance and stability. The interface modification and bulk doping are the two basic strategies. Fluorine (F)-containing materials are highly favored because of their unique hydrophobicity and coordination ability. This review discusses the basic characteristics of F, and the basic principles of improving the photovoltaic performance and stability of PSC devices using F-containing materials. We systematically summarized the latest progress in the application of F-containing materials to achieve efficient and stable PSCs on several key interface layers. It is believed that this work will afford significant understanding and inspirations toward the future application directions of F-containing materials in PSCs, and provide profound insights for the development of efficient and stable PSCs.

Decoupling excitons from high-frequency vibrations in organic molecules

The coupling of excitons in π-conjugated molecules to high-frequency vibrational modes, particularly carbon–carbon stretch modes (1,000–1,600 cm−1) has been thought to be unavoidable1,2. These high-frequency modes accelerate non-radiative losses and limit the performance of light-emitting diodes, fluorescent biomarkers and photovoltaic devices. Here, by combining broadband impulsive vibrational spectroscopy, first-principles modelling and synthetic chemistry, we explore exciton–vibration coupling in a range of π-conjugated molecules. We uncover two design rules that decouple excitons from high-frequency vibrations. First, when the exciton wavefunction has a substantial charge-transfer character with spatially disjoint electron and hole densities, we find that high-frequency modes can be localized to either the donor or acceptor moiety, so that they do not significantly perturb the exciton energy or its spatial distribution. Second, it is possible to select materials such that the participating molecular orbitals have a symmetry-imposed non-bonding character and are, thus, decoupled from the high-frequency vibrational modes that modulate the π-bond order. We exemplify both these design rules by creating a series of spin radical systems that have very efficient near-infrared emission (680–800 nm) from charge-transfer excitons. We show that these systems have substantial coupling to vibrational modes only below 250 cm−1, frequencies that are too low to allow fast non-radiative decay. This enables non-radiative decay rates to be suppressed by nearly two orders of magnitude in comparison to π-conjugated molecules with similar bandgaps. Our results show that losses due to coupling to high-frequency modes need not be a fundamental property of these systems.

Multifunctional buried interface modification of SnO2-based planar perovskite solar cells via phosphorus hetero-phenanthrene flame retardants

Tin dioxide (SnO2) is widely utilized for the cost-effective electron transport layer (ETL) in perovskite solar cells (PSCs) owing to its excellent optoelectronic properties. However, the surface defect states present in SnO2 ETL prepared by conventional solution methods seriously hinder the further improvement of device photovoltaic performance. It is urgently essential to develop a facile strategy to effectively minimize the adverse effects of SnO2 ETL on PSCs. Herein, a phosphorus hetero-phenanthrene flame retardant, DOPO, is introduced as a multifunctional surface modifier to improve the interfacial properties between SnO2 ETL and perovskite. Through systematic characterization analysis, the PO group in DOPO not only passivates the defective states on the surface of SnO2 ETL, but also provides chemical chelation sites for the uncoordinated Pb2+ ions in the upper perovskite structure to improve the film crystalline quality. Eventually, the photoelectric conversion efficiency (PCE) of the optimized device is improved from an initial 19.74 %–22.57 %, along with significantly improved device stability. This work provides an important reference for the development of new multifunctional interface modification materials required for SnO2-based planar PSCs with excellent properties.

Improvement of Thermal Stability and Photoelectric Performance of Cs2PbI2Cl2/CsPbI2.5Br0.5 Perovskite Solar Cells by Triple-Layer Inorganic Hole Transport Materials.

Conventional hole transport layer (HTL) Spiro-OMeTAD requires the addition of hygroscopic dopants due to its low conductivity and hole mobility, resulting in a high preparation cost and poor device stability. Cuprous thiocyanate (CuSCN) is a cost-effective alternative with a suitable energy structure and high hole mobility. However, CuSCN-based perovskite solar cells (PSCs) are affected by environmental factors, and the solvents of an HTL can potentially corrode the perovskite layer. In this study, a Co3O4/CuSCN/Co3O4 sandwich structure was proposed as an HTL for inorganic Cs2PbI2Cl2/CsPbI2.5Br0.5 PSCs to address these issues. The Co3O4 layers can serve as buffer and encapsulation layers, protecting the perovskite layer from solvent-induced corrosion and enhancing hole mobility at the interface. Based on this sandwich structure, the photovoltaic performances of the Cs2PbI2Cl2/CsPbI2.5Br0.5 PSCs are significantly improved, with the power conversion efficiency (PCE) increasing from 9.87% (without Co3O4) to 11.06%. Furthermore, the thermal stability of the devices is also significantly enhanced, retaining 80% of its initial PCE after 40 h of continuous aging at 60 °C. These results indicate that the Co3O4/CuSCN/Co3O4 sandwich structure can effectively mitigate the corrosion of the perovskite layer by solvents of an HTL and significantly improves the photovoltaic performance and thermal stability of devices.

Spontaneous Formation of 1D/3D Perovskite Heterojunctions for Efficient Inverted Perovskite Solar Cells

AbstractInterfacial modification is a key strategy for improving the performance of perovskite photovoltaic devices. While the modification of the top surface of the perovskite active layer is well established, engineering of the buried interface is highly challenging. Here, the spontaneous formation of a 1D/3D perovskite heterojunction at the buried interface of a perovskite active layer by incorporating choline acetate alongside the perovskite precursors is reported. Importantly, extensive spectroscopic and microscopic characterization and solid‐state nuclear magnetic resonance experiments demonstrate the formation of phase‐pure 1D and 3D domains. The 1D/3D junction results in a suppression of the defect states and an improved energetic level alignment at the buried interface, leading to a maximum power conversion efficiency of >24% when incorporated in inverted architecture perovskite solar cells. This work introduces a versatile approach to the modification of the buried interface of the perovskite active layer.

Graphene oxide-titanium oxide-polyaniline hybrid materials for high-performance dye-sensitized solar cells

A new solar cell that comprises a graphene oxide and titanium oxide nanoparticle (NP) composite with graphitized polyaniline (PANI) has been tested in polymer solar cells (PSCs). In this study, a series of conjugated polymers were synthesized and evaluated as the absorber and hole-transport layer materials in organic solar cells, demonstrating the significant impact of the chemical structure of the polymers on solar cell performance. The incorporation of graphene oxide (GOX) and titanium oxide TiO2 NP in conjugated polymers, particularly when graphitized within the PANI layer, led to improved open-circuit voltages compared to structurally similar polymers without NP. The morphology of the composite films was analyzed and related to the photovoltaic performance of polymers synthesized with polyaniline PANI-base and PANI-salt. Optimal NP addition in PANI-salt, PANI-base, PANI-base-TiO2, and PANI-base-GOX resulted in open-circuit voltages and efficiencies of 433 mV and 3.67%, 250 mV and 0.595%, 310 mV and 1.358%, and 520 mV and 2.366%, respectively. This study underscores the importance of polymer film uniformity in the performance of PSCs, with the highest efficiency obtained using a conjugated polymer with the best PANI-salt and PANI-base-GOX films. The research sheds light on the relationship between polymer structure and device photovoltaic performance, which is crucial for the design of new polymeric materials for efficient use and stable OSCs and PSCs.

Highly Stable Perovskite Solar Cells with Protective Layers Obtained via Interfacial Modification

Currently, achieving both high efficiency and long‐term stability is crucial for the successful application of perovskite solar cells (PSCs). Grain boundary (GB) defects significantly impact the stability of PSCs, and passivating these GBs remains a major challenge. Herein, the surfactant dodecyltrimethylammonium chloride (DTAC) is dissolved in low‐polarity chlorobenzene (CB) at 58 °C to modify the interface of MAPbI3 film, and DTAC reacts with MAPbI3 film surface to generate a protective layer that can be covered on the perovskite grains, effectively reducing the expose GBs. Additionally, the hydrophobic alkyl chains of DTA+ and the strong chemical bond between the Cl− and Pb2+ ions further enhance the resistance of the perovskite surface layer to heat, moisture, and oxidation. Due to the passivation of iodine vacancy defects, the photo‐stability of unencapsulated DTAC devices is significantly improved. By passivating surface and GBs defects of the MAPbI3 perovskite crystals, the power conversion efficiency of the low‐temperature carbon‐based PSCs treated by DTAC is 15.03% compared to 13.97% for the control device. This study offers another referable strategy for enhancing the thermal, moisture, light, and oxygen stability of perovskite materials while considering the photovoltaic performance of devices.

Advancements in nanohybrids: From coordination materials to flexible solar cells

This comprehensive review explores the forefront of nanohybrid materials, focusing on the integration of coordination materials in various applications, with a spotlight on their role in the development of flexible solar cells. coordination material-based nanohybrids, characterized by their unique properties and multifunctionality, have garnered significant attention in fields ranging from catalysis and sensing to drug delivery and energy storage. the discussion investigates the synthesis methods, properties, and potential applications of these nanohybrids, underscoring their versatility in materials science. Additionally, the review investigates the integration of coordination nanohybrids in perovskite solar cells (PSCs), showcasing their ability to enhance the performance and stability of next-generation photovoltaic devices. the narrative further expands to encompass the synthesis of luminescent nanohybrids for bioimaging purposes and the development of layered two-dimensional (2D) material-based nanostructured hybrids for energy storage and conversion. the exploration culminates in an examination of the synthesis of conductive polymer nanostructures, elucidating their potential in drug delivery systems. lastly, the article discusses the cutting-edge realm of flexible solar cells, emphasizing their adaptability and lightweight design. Through a systematic examination of these diverse nanohybrid materials, this review sheds light on the current state of the art, challenges, and prospects, providing valuable insights for researchers and practitioners in the fields of materials science, nanotechnology, and renewable energy.

Uncovering chemical structure-dependency of ionic liquids as additives for efficient and durable perovskite photovoltaics

Ionic liquids (ILs) have garnered significant attention in the field of perovskite solar cells (PSCs) due to their versatile capabilities in manipulating the crystallization kinetics, optimizing the morphology, and effectively passivating defects, leading to high-efficiency and long-term stability. While previous studies have mostly focused on individual ILs or different anions and their application in PSCs, the distinctive distribution of cations and anions within ILs underscores the significance of optimizing cationic structures and elucidates the particular role of cations in ILs on device performance. In this work, the implications of juxtaposing ILs incorporating carboxyl-functionalized imidazolium cations against conventional imidazolium-based counterparts on the crystallization kinetics, perovskite film quality, and the photovoltaic performance of perovskite devices. This strategy involving carboxyl-functionalized cations in ILs with a higher affinity to coordinate Pb2+, supported by chemical spectroscopy testing and a quantitative measure of the bond strength via Crystal orbital Hamiltonian group (COHP) calculations. The modified ILs more prominently results in enhancing the degree of PbI2 conversion into perovskite, slowing down crystallization rates and inducting formation of higher-quality perovskite films. Benefitting from the strong chemical interaction provided carboxyl-functionalized cations and widespread distribution of carboxyl-functionalized cations throughout the perovskite films, accomplishing comprehensive synergistic passivation of defects in perovskite films. This led to the suppression of non-radiative recombination and enhanced carrier transport properties. The incorporation of carboxyl modified ILs with suitable chemical structures resulted in a remarkable enhancement of the champion power conversion efficiency (PCE) to 24.21% in the ILs-treated device, coupled with excellent long-term stability.

Low‐Cost Metallization Based on Ag/Cu Fingers for Exceeding 25% Efficiency in Industrial Silicon Heterojunction Solar Cells

Although Ag‐coated Cu technology is considered to be an effective approach to mitigate the metallization expenses associated with silicon heterojunction (SHJ) solar cells, there is limited reporting on the photovoltaic performance and reliability of devices employing Ag/Cu electrodes. Herein, industrial SHJ solar cells were successfully fabricated, yielding an average efficiency of 25.18% with bifacial Ag/Cu fingers, which caused a 0.13% decline in efficiency but saved 46% in Ag consumption when compared to traditional Ag fingers. Performance degradation is demonstrated to originate essentially from the front rather than rear Ag/Cu fingers, as revealed by a comprehensive analysis of resistances enhancement and optical losses. Notably, the Ag/Cu fingers exhibited 1.4% lower printed qualification rate and similar high‐temperature stabilities in contrast to Ag fingers. In the results, valuable insights were provided for further optimization of low‐cost and high‐efficiency SHJ solar cells based on Ag/Cu electrodes.

Enhancing the indoor performance of organic photovoltaic devices: interface engineering with an aminobenzoic-acid-based self-assembled monolayer

Significant advances in the performance of organic photovoltaic (OPV) devices can facilitate their use in internet of things applications. However, achieving excellent photostability and high efficiency using stable, efficient OPV devices in indoor settings is considerably difficult. To address this issue, a zinc oxide (ZnO) electron transport layer (ETL) was modified with a self-assembled monolayer of 4-aminobenzoic acid (ABA) in the present study, and the impact of this modification was correlated with the indoor performance of an OPV device with the PM6:L8-BO photoactive layer. The ABA-treated ZnO ETL exhibited a significant reduction in the work function (from 4.51 to 4.04 eV), surface roughness (from 0.201 to 0.177 nm), and hydrophilicity of an indium-tin-oxide electrode; this aided in selectively extracting charge carriers from the device and minimizing trap-assisted recombination losses. Additionally, the ABA treatment of the ZnO ETL considerably enhanced the electron mobility and recombination resistance. It reduced the trap density, thereby enabling the ZnO/ABA-based device to achieve improved performance. Consequently, the ZnO/ABA-based device exhibited a noteworthy 14.68% higher maximum power output than that of the device without any ZnO surface modification under 1000 lx halogen (HLG) illumination (P out, max = 354.48 and 309 µA cm−2, respectively). Moreover, under thermal illumination conditions (1000 lx HLG lighting), the ZnO/ABA-based device sustained ∼74% of its initial power conversion efficiency over 120 h, significantly higher than its ABA-free equivalent (∼55%).

Bismuth in Lead–Tin Alloy Perovskites: Effect on Material Properties and Photovoltaic Device Performance

Bismuth in Lead–Tin Alloy Perovskites: Effect on Material Properties and Photovoltaic Device Performance

Completely annealing-free flexible Perovskite quantum dot solar cells employing UV-sintered Ga-doped SnO2 electron transport layers

The electron transport layer (ETL) is a critical component in perovskite quantum dot (PQD) solar cells, significantly impacting their photovoltaic performance and stability. Low-temperature ETL deposition methods are especially desirable for fabricating flexible solar cells on polymer substrates. Herein, we propose a room-temperature-processed tin oxide (SnO2) ETL preparation method for flexible PQD solar cells. The process involves synthesizing highly crystalline SnO2 nanocrystals stabilized with organic ligands, spin-coating their dispersion, followed by UV irradiation. The energy level of SnO2 is controlled by doping gallium ions to reduce the energy level mismatch with the PQD. The proposed ETL-based CsPbI3-PQD solar cell achieves a power conversion efficiency (PCE) of 12.70%, the highest PCE among reported flexible quantum dot solar cells, maintaining 94% of the initial PCE after 500 bending tests. Consequently, we demonstrate that a systemically designed ETL enhances the photovoltaic performance and mechanical stability of flexible optoelectronic devices.

Relationship Between Energy Efficiency Conversion Efficiency and Dynamic Performance of Solar Cells

First, this paper discusses the two most important modes of solar energy utilization - photoelectric and photothermal. Then, the main types, research status and future development of solar cells are described in this paper. A mathematical model is established to describe the performance of photovoltaic devices. The model is simulated and analyzed by MATLAB, PSIM and other software. Various flexible "photovoltaic +" solar energy application technologies are briefly described. The results show that the model is established by the characteristic parameters. If two different solar cells are combined together, their electrical performance can be reflected by appropriate adjustment of some parameters in the system.

Alternative during‐growth chlorination of sputtered CdTe films and their implementation as activating layers in CdS/CdTe solar cells

AbstractCadmium telluride is an efficient light absorbing material successfully used in solar cell technology. The efficiency of such photovoltaic devices is strongly dependent on post‐deposition thermal treatments in the presence of chlorine. The benefits of this process on the absorbing layer include removal of intragrain defects, grain growth enhancement, and grain boundaries passivation. The absorber chlorination is a crucial step for which CdCl2 is the most common choice. Its use, however, has been overshadowed by the toxicity of Cd‐ and Cl‐containing vapors and residues. In this work, chlorine was incorporated in CdTe films during growth using sputtering targets with different chloride compounds: CdCl2, TeCl4, BaCl2, CaCl2, or LiCl. After characterizing these films, CdTe:CdCl2 and CdTe:TeCl4 were selected as feasible absorbers for testing their performance in photovoltaic devices. Efficiencies near 7% were obtained in as‐grown unoptimized cells in which the absorber consisted of two layers: pristine CdTe and CdTe:CdCl2 or CdTe:TeCl4. The chlorinated layers acted as Cl sources for the adjacent CdTe and CdS, which produced a homogeneous distribution of chlorine throughout the cell. In the during‐growth activating‐layer (DG‐AL) method used here, the chlorine diffusion during growth had a doping effect, passivated grain boundaries and defects, improved the back contact characteristics by reducing the CdTe work function, and lowered the pinhole formation probability by producing a compact chlorinated CdTe layer.

Improvement of the photoelectrical properties of chemical bath-deposited Sb2S3 thin films with low copper doping

The chemical bath deposition method was used to prepare Cu-doped Sb2S3 thin films from complexes of Cu and Sb with triethanolamine. The as-deposited films with orange coloration had good adherence to the substrate. After an annealing treatment at 300 °C for 30 min in an Ar atmosphere, the resulting films acquired a brown color and exhibited the orthorhombic phase of Sb2S3 with the preferential growth of [hk0] grains. The Sb2S3 films were formed by rod-shaped nanoparticles, while the insertion of Cu ions in Sb2S3 promoted the formation of ribbon-like structures. The analysis of optical properties indicated the narrowing of bandgap energy from 1.9 to 1.8 eV due to the presence of Cu ions. In addition, the photoconductivity of the films increased from 8.3 × 10–6 to 30.5 × 10–6 Ω−1cm−1, while the photosensitivity factor was enhanced by more than 3 times. The performance of photovoltaic devices based on CdS/Sb2S3 and CdS/Cu:Sb2S3 heterojunctions were investigated. Compared with the device using a Sb2S3 layer, the one using a Cu-doped Sb2S3 layer exhibited an increase in open circuit voltage from 118.2 to 205 mV, short circuit current density from 0.14 to 0.34 mA/cm2 and conversion efficiency from 0.02 to 0.12%. The best performance was obtained by a photovoltaic device with a 500 nm Cu-doped Sb2S3 layer reaching an open circuit voltage of 226 mV, a short circuit current density of 0.94 mA/cm2 and conversion efficiency of 0.32%.

Efficient and Stable All-Polymer Solar Cells Enabled by Dual Working Mechanism.

Ternary strategy with integration characteristics and adaptability is a simple and effective method for blooming of the performance of photovoltaic devices. Herein, a novel wideband gap polymer donor PBB2-Hs is synthesized as the guest component to optimize all-polymer solar cells (all-PSCs). High-energy photon absorption and long exciton lifetime of PBB2-Hs constitute efficient energy transfer. Good miscibility and cascade energy levels promote the formation of alloy-like structure between PBB2-Hs and host system. The dual working mechanisms greatly improve photon capture and charge transfer in active layers. Additionally, the introduction of PBB2-Hs also optimizes the ordered molecular stacking of acceptors and suppresses molecular peristalsis. Upon adding 15 wt% PBB2-Hs, the ternary all-PSC achieved a champion efficiency of 17.66%, and can still maintain 82% photostability (24h) and 91% storage stability (1000h) of the original PCE. Moreover, the strong molecular stacking and entanglement between PBB2-Hs and the host material increased the elongation at break of ternary blend film by 1.6 times (16.2%), allowing the flexible device to maintain 83% of the original efficiency after 800 bends (R = 5mm). This work highlights the effectiveness of guest polymer on simultaneously improving photovoltaic performance, photostability and mechanical stability in all-PSCs.

Device modelling and numerical analysis of high-efficiency double absorbers solar cells with diverse transport layer materials

Recently, a lot of focus has been placed on cesium lead iodide (CsPbI3) since it is considered a potentially useful inorganic halide perovskite with improved stability. Moreover, another potential absorber material is the mixed chalcogenide CZTSSe, which is abundant on Earth, cheap, environmentally acceptable, and has excellent photovoltaic performance. This research numerically simulated a novel double absorber solar cell structure employing CsPbI3 and CZTSSe absorbers in the active layer in SCAPS-1D. The current study analyses the effects of various electron and hole transport materials, back contact material's work functions, working temperatures, variations in defect concentration, and absorber thickness on the performance of photovoltaic devices. After researching a variety of distinct arrangements of double absorber solar cells, it was realized that the FTO/STO/CsPbI3/CZTSSe/NiO/W cell configuration exhibited the best overall performance with an open circuit voltage (Voc) at 1.0207 V, a short circuit current density (Jsc) at 41.815426 mA/cm2, Fill Factor (FF) at 87.50 %, and a Power Conversion Efficiency (PCE) at 37.35 %. The modeling of the device showed that a thickness of around 1.4 µm for the CZTSSe absorber is optimal. This simulation shows that when the working temperature in the cell and the defect concentration in the absorber increase, the efficiency of the device reduces uniformly, and the device is stable at 300 K temperature. In conclusion, if the material's work function is greater than 5.20 eV, then it is suitable for use as an anode.

Influence of ZnO/MWCNTs based hybrid electrodes for boosting the performance of photovoltaic and supercapacitor devices

In this work, multi-wall carbon nanotubes (MWCNTs with 1, 3 and 5 wt.%) are mixed with zinc oxide (ZnO) to prepare nanocomposites for energy conversion and storage applications. Further, UV–Vis spectra of synthesized pure ZnO and ZnO/MWCNTs nanocomposite material shows enhanced light absorption in the visible region. Hexagonal wurtzite crystal structure of the nanocomposites is confirmed by X-ray diffraction (XRD) spectra. Field emission scanning electron microscopy (FE-SEM) and High resolution-transmission electron microscopy (HR-TEM) images explores the formation of nanocomposite with flake like ZnO and tube structured MWCNTs at nanoscale region. Dye sensitized solar cells (DSSC) are constructed with pure and nanocomposite material as photoanode and the effect of addition of MWCNTs on the performance of solar cells are studied. Further, the cyclic voltammetry (CV), galvanic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) are employed to examine the electrochemical characteristics of the prepared electrode in a 1 M Na2SO4 electrolyte. In three electrode configuration, the CV and GDC curves exhibits good reversibility and attains a specific capacitance value of 115.7 F g−1 with the addition of MWCNTs onto the ZnO. Also, the asymmetric supercapacitor device exhibits the improved storage performance. The EIS spectra shows lowest Rs and Rct resistance, indicating the prepared electrode is favorable for DSSC and supercapacitor application.

Mapping Uncharted Lead-Free Halide Perovskites and Related Low-Dimensional Structures.

Research on perovskites has grown exponentially in the past decade due to the potential of methyl ammonium lead iodide in photovoltaics. Although these devices have achieved remarkable and competitive power conversion efficiency, concerns have been raised regarding the toxicity of lead and its impact on scaling up the technology. Eliminating lead while conserving the performance of photovoltaic devices is a great challenge. To achieve this goal, the research has been expanded to thousands of compounds with similar or loosely related crystal structures and compositions. Some materials are "re-discovered", and some are yet unexplored, but predictions suggest that their potential applications may go beyond photovoltaics, for example, spintronics, photodetection, photocatalysis, and many other areas. This short review aims to present the classification, some current mapping strategies, and advances of lead-free halide double perovskites, their derivatives, lead-free perovskitoid, and low-dimensional related crystals.