Power Conversion Efficiency Of Device Research Articles

Comprehensive Design and Analysis of Thin Film Sb2S3/CIGS Tandem Solar Cell: TCAD Simulation Approach

Abstract This research presents a design and analysis of a tandem solar cell, combining thin film wide bandgap Sb2S3 (1.72 eV) and narrow bandgap CIGS (1.15 eV) for the top and bottom sub-cells, respectively. The integration of all thin film layers enhances flexibility, rendering the tandem solar cell suitable for applications such as wearable electronics. To optimize the power conversion efficiency (PCE) of the tandem solar device, advanced technology computer-aided design (TCAD) simulation tools are employed to estimate loss mechanisms and fine-tune parameters for each layer. An experimentally validated optoelectronic model is introduced, calibrated and validated against fabricated reference solar cells for the individual top and bottom cells. The calibrated model is then utilized to propose optimization routines for the Sb2S3/CIGS tandem solar cell. The initial tandem cell exhibits a JSC of 15.72 mA/cm2 and a PCE of 15.36%. The efficiency drop in the tandem configuration is identified primarily in the top cell. A systematic optimization process for the top cell is initiated, exploring various configurations, including HTL-free and ETL-free setups. Moreover, an np homojunction structure for the top cell is proposed. Optimization routines are applied that involve determining optimal thickness and doping concentration of the n-layer, investigating the effect of p-layer doping concentration, and exploring the influence of the work function of the front contact. As a result, the tandem cell efficiency is significantly improved to 23.33% at the current matching point (CMP), with a JSC of 17.15 mA/cm2. The findings contribute to the advancement of thin-film tandem solar cell technology, showcasing its potential for efficient and flexible photovoltaic applications.

Implementation of a Multi-Functional-Group Strategy for Enhanced Performance of Perovskite Solar Cells through the Incorporation of 3-Amino-4-Phenylbutyric Acid Hydrochloride.

Reducing the defect density of perovskite films during the crystallization process is critical in preparing high-performance perovskite solar cells (PSCs). Here, a multi-functional molecule, 3-phenyl-4-aminobutyric acid hydrochloride (APH), with three functional groups including a benzene ring, ─NH3 + and ─COOH, is added into the perovskite precursor solution to improve perovskite crystallization and device performance. The benzene ring increases the hydrophobicity of perovskites, while ─NH3 + and ─COOH passivate defects related to I- and Pb2+, respectively. Consequently, the power conversion efficiency (PCE) of the optimal device increased to 24.65%. Additionally, an effective area of 1 cm2 with a PCE of 22.45% is also prepared using APH as an additive. Furthermore, PSCs prepared with APH exhibit excellent stability by 87% initial PCE without encapsulation after exposure at room temperature under 25% humidity for 5000 h and retaining 70% of initial PCE after aging at 85°C in an N2 environment for 864 h.

Revealing the Roles of Guanidine Hydrochloride Ionic Liquid in Ion Inhibition and Defects Passivation for Efficient and Stable P erovskites Solar Cells.

As a result of full-scale ongoing global efforts, the power conversion efficiency (PCE) of the organic-inorganic metal halide perovskite has skyrocketed. Unfortunately, the long-term operational stability for commercialization standards is still lagging owing to intrinsic defects such as ion migration-induced degradation, undercoordinated Pb2+, and shallow defects initiated by disordered crystal growth. Herein, we employed multifunctional, non-volatile tetra-methyl guanidine hydrochloride [TMGHCL] ionic liquid (IL) as an additive to elucidate defects' passivation effects on organic-inorganic metal halide perovskite. More specifically, the formation of hydrogen bonds between H+ in GA+ and I- and coordinate bonding between Cl- and undercoordinated PbI2+could significantly passivate these defects. The hypothesis was confirmed by both experimental and DFT simulations displaying that the optimized ratio of IL integration restrains ion migration, improving grains' size, and significantly elongating the carrier lifetime. Remarkably, the modified cell achieved a peak efficiency of 22.00% with negligible hysteresis, compared to the control device's PCE of 20.12%. In addition, the TMGHCL-based device retains its 93.29% efficiency after 16 days of continuous exposure to air. This efficient approach of adding IL to perovskites absorber can produce high PCE and has strong commercialization potential.

Polyvinyl Chloride-Based Luminescent Downshifting Film with High Flame Retardancy and Excellent UV Resistance for Silicon Solar Cells.

Solar power generation, as a clean energy source, has significant potential for development. This work reports the recent efforts to address the challenge of low power conversion efficiency in photovoltaic devices by proposing the fabrication of a luminescence downshifting layer using polyvinyl chloride (PVC) with added fluorescent dots to enhance light utilization. A photoluminescent microsphere (HCPAM) is synthesized by cross-linking hexachlorocyclotriphosphazene, 2-iminobenzimidazoline, and polyethyleneimine. Low addition of HCPAM can improve the fire safety of PVC films, raising the limiting oxygen index of PVC to 32.4% and reducing the total heat release and smoke production rate values by 14.5% and 42.9%, respectively. Additionally, modified PVC film remains a transparency of 88% and shows down-conversion light properties. When the PVC+1%HCPAM film is applied to the solar cell, the short-circuit current density increases from 42.3 to 43.8mAcm-2, resulting in a 7.0% enhancement in power conversion efficiency. HCPAM also effectively delays the photooxidative aging of PVC, particularly at a 3% content, maintaining the surface morphology and optical properties of PVC samples during ultraviolet aging. This study offers an innovative strategy to enhance the fire and UV-resistant performance of PVC films and expand their applications in protecting and efficiently utilizing photovoltaic devices.

Hydrovoltaic Materials and Devices: From Synthetic Materials, Macroscopic Biomaterials, to Micro Biomaterials

Much progress has been made in hydrovoltaic materials and devices. However, the power conversion efficiency of hydrovoltaic devices is still low. One of the main factors that determine the efficiency is the properties of hydrovoltaic materials. Herein, the research status of hydrovoltaic materials is summarized from the perspectives of synthetic materials, macroscopic biomaterials, and micro biomaterials, as well as the hydrovoltaic devices based on these materials.

In-situ reaction modification of isocyanate derivatives with hole-transport units on perovskite film surface for efficient and stable solar cells

FAPbI3 perovskite solar cells (PSCs) have attracted widespread research attention. The interfacial properties play a crucial role in perovskite defect passivation and interfacial carrier transport, significantly influencing the power conversion efficiency (PCE) and stability of devices. Here, a novel interface modification strategy of in-situ reaction on perovskite surface is proposed. A molecule N,N′-bis(4-isocyanatophenyl)-N,N′-di-p-tolyl-[1,1′-biphenyl]-4,4′-diamine (TPD-NCO), involving a hole-transporting unit TPD was synthesized. The highly reactive isocyanate (NCO) groups addition-reacted with formamidine ions (FA+) from the FAPbI3 surface, forming urea with firm covalent bonds. The resulting stable modification smoothened the interface, and its urea groups coordinated with Pb2+ and formed hydrogen bonds with I-, thereby passivating the surface defects and inhibiting ion migration. Moreover, the hole-transporting units were firstly anchored through this covalent modification as a p-type dopant to lower the interface energy barrier for hole extraction. The PCE of target devices increased from 22.82% to 24.46%, which also remained 93% for 5460 h under high humidity (65% RH), 87% for 1060 h under 75 °C, and 77% for 420 h under maximum power point (MPP) operation at 50 °C, indicating both excellent efficiency and long-term stabilities. This work displays the value of both firm and hole-conductive features in in-situ reactive interface modification.

Perovskite/La-BDC heterojunction enhances the performance of carbon-based perovskite solar cells

Carbon-based Perovskite Solar Cells (C-PSCs) present a promising avenue for enhancing the stability and commercialization of PSCs. However, the power conversion efficiency (PCE) of C-PSCs still lags behind that of metal-based PSCs. In this study, La-BDC (La-MOF prepared by La3+ and ligand H2BDC) has successfully synthesized using a simple hydrothermal method and then directly introduced into CH3NH3PbI3 (MAPbI3) perovskite precursor solution to prepare perovskite/La-BDC heterojunction structure with remarkable properties in light absorption, hydrophobicity, and crystallinity. By incorporating this structure, the PCE of C-PSCs with an FTO/SnO2/MAPbI3/La-BDC/Carbon architecture was effectively enhanced. The presence of CO functional group in La-BDC effectively reduced interface defects while improving carrier separation efficiency, and successfully passivated the free Pb2+ ions within the perovskite. Remarkably, the La-BDC-based device achieved a superior PCE of 14.95%, surpassing the pristine device's PCE by an impressive margin of 20.37%. Moreover, even after a 31 days period of air storage (temperature range of 15–25℃, humidity range of 15–30%), the La-BDC-based devices maintained over 90% of the initial performance, demonstrating excellent stability. This study provides a facile and effective strategy for improving the PCE and stability of C-PSCs through implementing a La-BDC heterojunction structure， and provides a new idea for MOF materials in the field of PSCs.

A new alcohol-soluble dye-tetraphenyl porphyrin functionalized copolymer: Inside the role as a third component/cathode interlayer in halogen-free OSCs

Development and step-by-step characterizations of a novel cationic thiophene based copolymer (P1buP), including ionic phosphonium salt and dye-tetraphenylporphyrin (TPP) moiety in side chains, with an iconic property of solubility in a wide range of polar solvents is reported. Synthesized by using simple, low-cost, and straightforward procedures, the material is used to fabricate completely halogen-free (i.e., from ethanol) ternary organic solar cells (OSCs), in the presence of an alcohol-soluble ionic 3,4-dialkoxythiophene based homopolymer (P2buP) and a serinol-fullerene derivative (C60-Ser). Indeed, thanks to co-sensitization techniques, where multiple dyes harvest different parts of the solar spectrum, the power conversion efficiency of the best final device dramatically increases up to nearly 5.0%, as the light absorption is usually optimized. Additionally, since the use of a cathode interlayer in OSCs also plays a pivotal role in electron extraction and device stability, a possible application of the ionic TPP material as the interfacial layer is also investigated. Furthermore, to improve and optimize the best performing device, a successful post-metalation with Zn of the porphyrin core is carried out, and a ternary OSC (P1buP:P2buP:C60-Ser = 0.33:0.67:1 w/w) is fabricated, resulting in a photoconversion efficiency (PCE) of ~6.0%.

Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

Perovskite solar cells (PSCs) have made great advances in terms of power conversion efficiency (PCE), yet their subpar stability continues to hinder their commercialization. The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs. In this work, we propose a strategy to stabilize high-performance PSCs with PCE over 23% by introducing a cesium-doped graphene oxide (GO-Cs) as an interlayer between the perovskite and hole-transporting material. The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80 (the time where the device PCE reduces to 80% of its initial value) of 2143 hours of operation at the maximum powering point under one sun illumination.

Synchronous effect of coordination and hydrogen bonds boosting the photovoltaic performance of perovskite solar cells

Superior quality of perovskite film with perfect crystalline and low defect density is crucial for achieving excellent photovoltaic performance and durability of perovskite solar cells (PSCs), and regulation of growth of perovskite crystal and defects passivation by additive is remain challenge. Herein, two acyl molecules (Succinimide: SCI, and Hydantoin: HDT) were incorporated into perovskite precursor solution as additive. It can be found that the HDT molecule can not only passivate undercoordinated Pb2+ defects in perovskite films by the -C=O groups with coordination bonds, but also formed hydrogen bonds with I− by -NH- group, which effectively inhibited the formation of iodine vacancy defects and regulated growth rate of perovskite crystals, and the quality of perovskite films was optimized with enlarging grain size and reduced trap-density. Consequently, power conversion efficiency of HDT-based device was enhanced from 19.47 % to 21.00 %, with an enhancement of JSC and VOC. Moreover, the HDT-based device without encapsulation retained 83.7 % of its initial PCE after being aged at 10–20 % RH for 60 days. Obviously, such a study could provide a new strategy to optimize quality of perovskite film for boosting performance of PSCs.

Structurally Flexible 2D Spacer for Suppressing the Electron–Phonon Coupling Induced Non-Radiative Decay in Perovskite Solar Cells

HighlightsThe soft 2D material reduces the coupling strength between carriers and longitudinal optical phonons, releasing the mechanical stress of lattice vibration.The power conversion efficiency of rigid devices and flexible devices reaches 25.5% and 23.4%, respectively.

Utilizing Metal Oxide Thin Films for Device Engineering of Solution-Processed Organic Multi-Junction Solar Cells

Electron and hole transporting layers play a major role in high-performance and stable organic-based optoelectronic devices. This paper demonstrates detailed device engineering of multi-junction organic photovoltaics built on two different metal oxide-based electron and hole transport (buffer) layers prepared by thermal or solution-processed methods. The main focus is on the device processing parameters as well as practical details of preparation of buffer layers to give the research community a clear, step-by-step recipe to successfully replicate and build series and parallel connected multi-junction solution-based organic solar cells for their needs. Here, the recipes and deposition conditions of two metal oxide buffer layers are presented in detail, based on basic commercially available materials and tools, to achieve well-engineered tandem (multi-junction) solution-processed organic solar cells. The buffer layers have appropriate energy levels for electrical selectivity of anode and cathode electrodes, and they are highly stable and chemically compatible with processing of solution-based polymer solar cells. To demonstrate the engineering steps of multi-junction devices, the PCE10:PC70BM blend is used as the active layer for all subcells. Then, to improve the power conversion efficiency of the single-junction photovoltaic device, PCE10:PC70BM blend is used in combination with DPPx:PC70BM with different absorption spectra for bottom and top subcell active layers. An optimized series tandem device with 10.6% power conversion efficiency is demonstrated. Generally, the device structures reported here can also be used for other types of optoelectronic devices, such as light emitting diodes and photodetectors.

Investigating the influence of natural dye extracts from Ocimum gratissimum, Solanum melongena, Piper guineese, and their blend in the fabrication of perovskite solar cells

Perovskite solar cells (PSCs) represent a promising alternative to conventional silicon solar cells but face challenges like instability stemming from structural defects, environmental toxicity due to the selection of precursors and additives, and concerns regarding long-term reliability. To address these issues, we investigated the viability of cost-effective and eco-friendly PSCs by strategically incorporating natural dyes derived from indigenous plants, including Ocimum gratisimum, Solanum melongena, and Piper guineese, into the MAPbI3 perovskite crystal, using a two-step sequential drop-casting technique. The resulting perovskite films underwent comprehensive analysis for their structural, morphological, optical and elemental composition using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometer (UV–Vis) and energy dispersive X-ray microscopy (EDX). Performance evaluation was conducted through J-V curve analysis using a solar simulator. The XRD analysis revealed polycrystalline films with enhanced diffraction intensities corresponding to a hexagonal structure, and the UV–Vis analysis demonstrated substantial improvements in light absorption with improved optical properties. SEM studies provided crucial correlations between morphology and performance, with each sample exhibiting unique attributes, and EDX analysis confirmed essential elements within the films. The current density-voltage analysis demonstrated a 1.83 % power conversion efficiency (PCE) for the natural dye-doped device under air, surpassing the pristine device. This study advances the understanding of the synergies between natural dyes and perovskite materials, emphasizing their potential to enhance PSC efficiency. The findings underscore the considerations for designing and optimizing PSCs, paving the way for further exploration of natural dye-based approaches in sustainable photovoltaic technologies.

A benzobisoxazole-based polymer assisting high efficiency polymer solar cells

Ternary strategy is an effective method to optimize photovoltaic process and improve device performance. In this work, a benzobisoxazole-based conjugated polymer PBBO was designed and employed as the guest component for PM6:BTP-eC9 based devices. The polymer PBBO shows a large band gap of 2.16 eV and strong photoluminescence property, with efficient energy transfer observed between PBBO and PM6. The ternary blends not only form a cascaded energy level distribution, but also an alloy-like structure, which can effectively promote the exciton dissociation, charge transfer and efficiently suppress charge recombination. As a result, the power conversion efficiency (PCE) of the ternary device is substantially improved from 17.50% to 18.66% with the incorporation of PBBO guest component. Meanwhile, the ternary device shows good stability with retaining 86% of initial efficiency after storage for 2000 hours. This research demonstrates that the polymer PBBO would be an excellent photovoltaic material to optimize the performance of polymer solar cells.

Improving photovoltaic characteristics of CdS-based hybrid solar cells through Mn incorporation

CdS thin films, both with and without Mn-doping, were grown via chemical bath deposition on indium tin oxide-coated glass substrates for application in hybrid solar cells. X-ray diffraction analysis revealed that Mn doping led to a deterioration in the crystal quality of CdS samples, evidenced by increased microstrain and dislocation density. Mn atoms were interstitially incorporated into the CdS structure, resulting in an expansion of the unit cell volume. Morphological analysis indicated a decrease in grain size from 390 nm to 140 nm for 0 % and 2 % Mn-doped CdS samples, respectively, while maintaining the spherical shape of the CdS thin films. Mn doping also increased the transmittance of CdS thin films, with the highest transparency of 95 % at 580 nm achieved for the 2 % Mn-doped CdS sample. In comparison to undoped CdS (2.38 eV), the band gap of CdS samples initially decreased to 1.84 eV for 1 % Mn doping but significantly increased to 3.03 eV for 2 % Mn-doped CdS. Photoluminescence (PL) data indicated that 2 % Mn-doped CdS thin films exhibited the lowest peak intensity, suggesting that a high concentration of Mn atoms caused non-radiative charge recombination. Additionally, efficient exciton dissociation was observed between CdS:Mn and P3HT:PCBM (poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM)) layers in the 2 % Mn-doped CdS-based device, as per the PL results. Photovoltaic measurements demonstrated that compared to undoped CdS, 2 % Mn doping increased the power conversion efficiency of the CdS-based device from 0.070 % to 0.202 %, indicating an almost threefold increase in hybrid solar cell efficiency. This improvement is likely attributed to the development of a better interface between the CdS:Mn and P3HT:PCBM layers.

Performance analysis of A3B2X9 (Cs3Bi2I9) based perovskite photovoltaic tandem structure with crystalline Silicon (c-Si)

The efficiency of solar cells with single-junction utilizing organic-inorganic hybrid perovskites have attained a value more than 25.5%. The device power conversion efficiency (PCE) can be improved further either by optimizing the absorber layer (Perovskite film) or by investigating the novel device structures such as tandem based solar cells with perovskite and silicon. This combination of top cell (Perovskite solar cell) and bottom cell (Silicon solar cell) can improve the PCE which surpasses the Shockley-Queisser limit of single-junction solar cells by utilizing a wider range of solar spectrum. This paper presents an optimization and simulation of standalone Cs3Bi2I9 perovskite solar cell which was later integrated with a c-Si solar cell to simulate a tandem structure using SCAPS-1D software. The aim is to investigate the performance enhancement of the perovskite solar cell by optimizing it and stacking it on top of a high-efficiency c-Si solar cell using a four-terminal (4T) structure. At a short-circuit current density of 16.165 mA/cm2 and an open-circuit voltage of 1.41 V, the simulation findings demonstrate that the Cs3Bi2I9 perovskite solar cell exhibits a high-power conversion efficiency of 20.37%. The tandem structure demonstrates an enhanced power conversion efficiency of 31.59% which is significantly higher than the efficiency of the individual cells. The Cs3Bi2I9 perovskite solar cell is a great choice for application in tandem systems with c-Si solar cells for high-efficiency, according to the simulation results. This study provides valuable insights for the development of efficient perovskite/c-Si tandem solar cells.

Research on Wave Energy Converters

With the acceleration of the global warming process, the clean energy crisis is becoming serious; conventional energy is unlikely to solve the current crisis, so people pay attention to new energy. As wave energy is widely distributed, renewable, and clean, hundreds of wave energy converters emerge. In order to understand the research progress of wave energy converters better, this paper divides wave energy converters into overtopping type, oscillating water column type, and oscillating body type according to the working principle and divides the oscillating body type into oscillating float type and oscillating pendulum type by different ways of energy capture. Based on the classification, various types of engineering cases, physical tests and digital simulation, and other academic research results are summarized, especially the generation power and energy conversion efficiency of various devices, and some shortcomings and suggestions are put forward, hoping to provide help for readers to study wave energy generation converters.

High-performance intrinsically stretchable organic solar cells based on flexible spacer incorporated dimerized small-molecule acceptors

High power conversion efficiency (PCE), long-term stability, and mechanical robustness are important requirements for the practical applications of organic solar cells (OSCs). Herein, we develop a series of flexible spacer (FS)-incorporated dimerized small-molecule acceptors (DSMAs; DYBT-C0, DYBT-C4, and DYBT-C8) and demonstrate high-performance OSCs with a high PCE of 18.6%, excellent mechanical robustness (crack-onset strain (COS) = 32%) and photostability (t80% lifetime = 1735 h under 1-sun illumination). The incorporation of aliphatic FS units with optimal length effectively reduces the backbone rigidity of the DSMAs and increases the fraction of intermixed domains in the blend films, while maintaining excellent electron transport properties. The DYBT-C4-based OSCs demonstrate higher PCE (18.6%) and stretchability (COS = 32%) compared to the OSCs based on the monomer acceptor (MYT; PCE = 15.9% and COS = 10%) and DSMA without FS units (DYBT-C0; PCE =17.2% and COS = 17%). In addition, due to the reduced diffusion coefficient and higher glass transition temperature of DYBT-C4, the DYBT-C4-based OSCs exhibit photostability significantly higher than that of the OSCs fabricated using MYT (t80% lifetime= 36 h). Consequently, DYBT-C4-based intrinsically stretchable (IS)-OSCs exhibit high device stretchability (strain at PCE80% = 36%) and PCE of 14.3%, demonstrating potential for wearable applications.

Zirconium Oxide Doped Organosilica Nanodots as Light- and Charge-Management Cathode Interlayer for Highly Efficient and Stable Inverted Organic Solar Cells.

In this work, it is reported that zirconium oxide (ZrO2) doped organosilica nanodots (OSiNDs: ZrO2) with light- and charge-management properties serve as efficient cathode interlayers for high-efficiency inverted organic solar cells (i-OSCs). ZrO2 doping effectively improves the light harvesting of the active layer, the physical contact between the active layer, as well as the electron collection property by habiting charge recombination loss. Consequently, all devices utilizing the OSiNDs: ZrO2 cathode interlayer exhibit enhanced power conversion efficiency (PCE). Specifically, i-OSCs based on PM6:Y6 and PM6:BTP-eC9 achieve remarkable PCEs of 17.16% and 18.43%, respectively. Furthermore, the PCE of device based on PM6:Y6 maintains over 97.2% of its original value following AM 1.5G illumination (including UV light) at 100mWcm-2 for 600min.

Transferred Metal Electrodes for Perovskite Solar Cells with Doping‐Tuned Hole‐Transporting Layer

As an alternative technology to the standard evaporated metal top electrode in perovskite solar cells, the transfer method top electrode is featured with low cost, simple process, and ease of scalability. However, as the transfer method preparation of the less expensive metal electrodes (Ag and Cu) is explored, the mismatch between the hole‐transport layer and the top electrode results in anomalous photovoltaic properties. In this study, the work function of the hole‐transporting material is adjusted by changing the dopant content to achieve a good energy‐level match with either Ag or Cu electrode material. The power conversion efficiencies of perovskite devices based on transferred Ag and Cu electrodes can reach 18.41% and 17.25%, respectively, which are comparable to the performance of the evaporated top electrode devices.