Enhanced Conversion Efficiency Research Articles

Simulation of multijunction solar cell interfaces for enhancement of the power conversion efficiency

Simulation of multijunction solar cell interfaces for enhancement of the power conversion efficiency

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.

Account of doping photocatalyst for water splitting

In the field of photocatalytic water splitting, the strategy of doping photocatalysts has emerged as a significant and extensively studied approach. Doping can effectively facilitate the modification of both the microstructure and energy band structure of the photocatalyst, addressing key performance limitations such as light absorption, position of the conduction and valence band minima (CBM and VBM), photogenerated carrier separation, and surface chemical reactions. In recent years, we have reported several works about the doping of rare earth elements into bismuth-based composite oxides. These endeavors are aimed at enhancing the conduction band minimum and achieving overall water splitting under visible light. Based on these bismuth-based composite oxides, we studied the effects of doping on the microstructures of photocatalysts, including exposed surfaces, surface properties, and defects. Recently, we introduce an innovative asymmetric doping technique—Selected Local Gradient Doping, intricately placing doped ions within nanocapsules. This approach allows for the gradual, controlled, and localized release of doped ions to the primary photocatalyst. Therefore, this account is to review our related research in the field of doping for photocatalytic water splitting. The primary focus on doping bismuth-based composite oxides and Asymmetry doping would significantly make contribution to the exploration of novel materials for photocatalytic water splitting under visible light and the enhancement of energy conversion efficiency.

Vacuum-Processed Propylene Urea Additive: A Novel Approach for Controlling the Growth of CH3NH3PbI3 Crystals in All Vacuum-Processed Perovskite Solar Cells.

In this study, we present a novel method for controlling the growth of perovskite crystals in the vacuum thermal evaporation process by utilizing a vacuum-processable additive, propylene urea (PU). By coevaporation of perovskite precursors with PU to form the perovskite layer, PU, acting as a Lewis base additive, retards the direct reaction between the perovskite precursors. This facilitates a larger domain size and reduced defect density. Following the removal of the residual additive, the perovskite layer, exhibiting improved crystallinity, demonstrates reduced charge recombination, as confirmed by a time-resolved microwave conductivity analysis. Consequently, there is a notable enhancement in open-circuit voltage and power conversion efficiency, increasing from 1.05 to 1.15 V and from 17.17 to 18.31%, respectively. The incorporation of a vacuum-processable and removable Lewis base additive into the fabrication of vacuum-processed perovskite solar cells offers new avenues for optimizing these devices.

Optimization of boron depletion for boron-doped emitter of N-type TOPCon solar cells

During the preparation of boron-doped emitters for TOPCon solar cells, boron atoms accumulate, forming a boron-rich layer (BRL). Oxidation, during the boron diffusion process, can eliminate the BRL. Prolonged oxidation which forms a SiO2 layer can remove the BRL, also act as a protective mask for the front surface. Nevertheless, during high-temperature thermal oxidation, boron will be redistributed. Boron reaches a higher equilibrium concentration in SiO2 than in the silicon wafer, and the SiO2/Si interface shifts inward during SiO2 formation. Simultaneously, the high temperature during oxidation prompts the boron inside the silicon wafer to diffuse deeper. The dual effects of oxidation and diffusion cause boron to be depleted near the surface of the silicon wafer. Boron depletion leads to a reverse bending of the energy band, which hampers carrier collection and impedes further enhancement of cell power conversion efficiency. In this paper, the oxidation process was mainly adjusted to reduce surface boron depletion, resulting in approximately 0.09%abs. increase in power conversion efficiency compared to pre-optimization.

Facile synthesis and application of hyperbranched TiO2 hollow spheres for enhancement of power conversion efficiency of CdSeTe quantum dot-sensitized solar cells

Facile synthesis and application of hyperbranched TiO2 hollow spheres for enhancement of power conversion efficiency of CdSeTe quantum dot-sensitized solar cells

Introduction of Co atoms into CdS thin films for improving photovoltaic properties

This paper represents a systematic work on the fabrication of chemical bath-grown CdS films with and without Co atoms and their photovoltaic performances in hybrid solar cells. Structural properties showed 1% Co-doping promoted crystal quality of CdS films. However, a poor crystal quality was developed above 3% Co concentrations. A reduction in sphere size of CdS samples was observed for 1% Co-doping which was ascribed to slow growth of film. Optical examination demonstrated CdS films with 1% Co-doping displayed the highest transparency of 85% in the visible and near-infrared regions, which were explained by the improvement of crystal quality. A maximum band gap of 2.43 eV was found for 1% Co-doped CdS films, whereas an increase in Co concentration to 7% led to a decline in the band gap of CdS that was attributed to sp-d exchange interaction. Photoluminescence data showed Co-doped CdS films had lower PL peak intensity than that of CdS, demonstrating a decrease in the number of intrinsic defects. Photovoltaic measurements displayed that the best efficiency of 0.488% was achieved for CdS-based device including 1% Co atoms, which were almost a seven-fold boost in overall efficiency compared to bare CdS-based device. The enhancement in power conversion efficiency originated from an increase in short-circuit current density of 1% Co-doped CdS-based photovoltaic cell.

Tri-chalcogenides (Sb2S3/Bi2S3) solar cells with double electron transport layers: design and simulation

To make technology accessible to everyone, it is essential to focus on affordability and durability of the devices. Antimony trisulfide (Sb2S3) and bismuth (III) sulfide (Bi2S3) are low-cost and stable materials that are commonly used in photovoltaic devices due to their non-toxic nature and abundance. These materials are particularly promising for photovoltaic applications as they are effective light-absorbing materials. In this study, we utilized the Solar cell Capacitance Simulator- One-Dimensional (SCAPS-1D) software to investigate the parameters of a double electron transport layer (ETL) solar cell based on Sb2S3/ Bi2S3. The parameters examined included thickness of the absorber layer, overall defect density, density of acceptors, radiative recombination coefficient, series and shunt resistance, and work function of the back contact. The solar cell structure studied was FTO/SnO2/CdS/ Sb2S3 and Bi2S3/Spiro-OMeTAD/Au. By incorporating a SnO2 electron transport layer (ETL) into the double ETL structure of Sb2S3 and Bi2S3 solar cells, we observed a significant enhancement in the power conversion efficiency (PCE). Specifically, the PCE increased to 19.71% for the Sb2S3 solar cell and 24.05% for the Bi2S3 solar cell. In contrast, without SnO2, the single ETL-based CdS solar cell achieved a maximum PCE of 18.27 and 23.05% for Sb2S3 and Bi2S3, respectively.

Multitone Waveform Design Toward Enhancing Conversion Efficiency for RF Electronics Detection

Multitone Waveform Design Toward Enhancing Conversion Efficiency for RF Electronics Detection

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.

Enhanced Detection of Novel Low‐Frequency Gene Fusions via High‐Yield Ligation and Multiplexed Enrichment Sequencing

AbstractPanel‐based methods are commonly employed for the analysis of novel gene fusions in precision diagnostics and new drug development in cancer. However, these methods are constrained by limitations in ligation yield and the enrichment of novel gene fusions with low variant allele frequencies. In this study, we conducted a pioneering investigation into the stability of double‐stranded adapter DNA, resulting in improved ligation yield and enhanced conversion efficiency. Additionally, we implemented blocker displacement amplification, achieving a remarkable 7‐fold enrichment of novel gene fusions. Leveraging the pre‐enrichment achieved with this approach, we successfully applied it to Nanopore sequencing, enabling ultra‐fast analysis of novel gene fusions within one hour with high sensitivity. This method offers a robust and remarkably sensitive mean of analyzing novel gene fusions, promising the discovery of pivotal biomarkers that can significantly improve cancer diagnostics and the development of new therapeutic strategies.

Enhanced Detection of Novel Low-Frequency Gene Fusions via High-Yield Ligation and Multiplexed Enrichment Sequencing.

Panel-based methods are commonly employed for the analysis of novel gene fusions in precision diagnostics and new drug development in cancer. However, these methods are constrained by limitations in ligation yield and the enrichment of novel gene fusions with low variant allele frequencies. In this study, we conducted a pioneering investigation into the stability of double-stranded adapter DNA, resulting in improved ligation yield and enhanced conversion efficiency. Additionally, we implemented blocker displacement amplification, achieving a remarkable 7-fold enrichment of novel gene fusions. Leveraging the pre-enrichment achieved with this approach, we successfully applied it to Nanopore sequencing, enabling ultra-fast analysis of novel gene fusions within one hour with high sensitivity. This method offers a robust and remarkably sensitive mean of analyzing novel gene fusions, promising the discovery of pivotal biomarkers that can significantly improve cancer diagnostics and the development of new therapeutic strategies.

Semiconductor–Semimetal Composite Engineering Enabling Record‐High Thermoelectric Power Density for Low‐Temperature Energy Harvesting

AbstractSustained thermoelectric efforts have concentrated on the enhancement of conversion efficiency of power generators, while simultaneously achieving high output power continues to lag. Specifically, the highest output power density of emerging Mg‐based modules reported so far is only half of that of commercial Bi2Te3‐based, mainly due to the low power factor of MgAgSb. Herein, homogenously distributed MgCuSb in situ nanoprecipitates in the MgAgSb matrix effectively optimized carrier concentration due to the effect of carrier injection from the metal–semiconductor Ohmic contact. As a result, a record‐high average power factor of 27.2 µW cm−1 K−2 is obtained in MgCu0.1Ag0.87Sb0.99 composite within the temperature range of 300–550 K, which is much higher than ever reported values of MgAgSb system. Benefiting from the combination of the optimized average power factor of p‐leg and low interface resistivity, a fabricated eight‐pair MgCu0.1Ag0.87Sb0.99/Mg3.2Bi1.5Sb0.5 module demonstrates an unprecedently high output power density of 2.9 W cm−2 under a temperature difference of 300 K, outperforming all low‐temperature advanced thermoelectric modules. Meanwhile, a competitive conversion efficiency of 7.65% is obtained simultaneously. The work significantly advances high‐power thermoelectric applications of Mg‐based modules in the field of low‐temperature sustainable energy harvesting.

Lead-free perovskite solar cell based on methyl ammonium tin iodide: Possible power conversion efficiency enhancement by device simulation

Although solar cells have the potential to create an endless amount of electrical power, their comparatively low power conversion efficiency draws the curiosity of both academics and industry. The primary goal of this research is to examine the performance of lead-free perovskite solar cells that use methyl ammonium tin iodide (CH3NH3SnI3) as the active material. The SCAPS-1D programme is employed for the simulation and analysis of the solar cells. The solar cell structure was analyzed computationally, and the resulting output was examined by comparing the I-V characteristic curves across different combinations of parameters. Various materials and combinations of parameters were explored in an effort to enhance the power conversion efficiency of solar cells based on CH3NH3SnI3. A series of comprehensive evaluations were undertaken to examine the influence of technical factors, including absorber layer thickness, defect density, and acceptor density, on performance. The acceptor density that yielded the best results was selected in order to improve the performance of the solar cell. The simulation results were acquired across a temperature range spanning from 300K to 450K, revealing enhanced stability within the range of typical ambient temperatures. The study produced encouraging findings, which included a short circuit current density of 30.81mA/cm2, an open circuit voltage of 1.25V, a fill factor of 80.35%, and a power conversion efficiency of 31.11%. This study has the potential to facilitate the development of environmentally sustainable, highly efficient, and cost-effective thin film solar cells based on CH3NH3SnI3, which exhibit noteworthy physical characteristics as alternatives to lead-containing perovskite solar cells.

Synergetic Near- and Far-Field Plasmonic Effects for Optimal All-Perovskite Tandem Solar Cells with Maximized Infrared Absorption.

The efficiency and reliability of perovskite solar cells have rapidly increased in conjunction with the proposition of advanced single-junction and multi-junction designs that allow light harvesting to be maximized. However, Sn-based compositions required for optimized all-perovskite tandem devices have reduced absorption coefficients, as opposed to pure Pb perovskites. To overcome this, we investigate near- and far-field plasmonic effects to locally enhance the light absorption of infrared photons. Through optimization of the metal type, particle size, and volume concentration, we maximize effective light harvesting while minimizing parasitic absorption in all-perovskite tandem devices. Interestingly, incorporating 240 nm silver particles into the Pb-Sn perovskite layer with a volume concentration of 3.1% indicates an absolute power conversion efficiency enhancement of 2% in the tandem system. We present a promising avenue for experimentalists to realize ultrathin all-perovskite tandem devices with optimized charge carrier collection, diminishing the weight and the use of Pb.

Understanding the Behaviors of Plasmon-Induced Hot Carriers and Their Applications in Photocatalysis.

Photocatalysis driven by plasmon-induced hot carriers has been gaining increasing attention. Recent studies have demonstrated that plasmon-induced hot carriers can directly participate in photocatalytic reactions, leading to great enhancement in solar energy conversion efficiency, by improving the catalytic activity or changing selectivity. Nevertheless, the utilization efficiency of hot carriers remains unsatisfactory. Therefore, how to correctly understand the generation and transfer process of hot carriers, as well as accurately differentiate between the possible mechanisms, have become a key point of attention. In this review, we overview the fundamental processes and mechanisms underlying hot carrier generation and transport, followed by highlighting the importance of hot carrier monitoring methods and related photocatalytic reactions. Furthermore, possible strategies for the further characterization of plasmon-induced hot carriers and boosting their utilization efficiency have been proposed. We hope that a comprehensive understanding of the fundamental behaviors of hot carriers can aid in designing more efficient photocatalysts for plasmon-induced photocatalytic reactions.

Remarkable enhancement of power conversion efficiency of silicon photovoltaic cell overlaying with novel metallic-polymer nanocomposites utilising immersion technique

Remarkable enhancement of power conversion efficiency of silicon photovoltaic cell overlaying with novel metallic-polymer nanocomposites utilising immersion technique

Electron transfer tuned by pressure-dependent aggregation-induced emission in InP/ZnS quantum dot–anthraquinone complexes

Electron transfer (ET) process is considered a substantial factor in influencing the photoelectric conversion efficiency of optoelectronic devices. While pressure has demonstrated effective tune ET, a comprehensive investigation into the mechanisms for both restraining and promoting ET remains elusive. Herein, we have performed measurements using in situ high-pressure steady-state photoluminescence (PL), Raman scattering spectra, and femtosecond transient absorption (fs-TA) spectroscopy on InP/ZnS quantum dot–anthraquinone (InP/ZnS QD-AQ) complexes. The experimental results have demonstrated that the pressure-suppressed ET process in the InP/ZnS QD-AQ complexes arises from both the aggregation-induced emission (AIE) effect of AQ in toluene and the quantum confinement effect of the InP/ZnS QDs. The reduction in the distance between InP/ZnS QD and AQ under pressure emerges as a key factor that promotes the ET process in the InP/ZnS QD-AQ complexes. Furthermore, we observed that the pressure not only enhances the ET process but also suppresses the auger recombination process in liquid phase I of toluene, consequently leading to an enhancement in the photoelectric conversion efficiency. This study contributes to understanding the mechanism of the ultrafast dynamic processes in the pressure-induced QD-receptor complexes, and it has great potential for preparing efficient and stable optoelectronic devices.

Enhancement of power conversion efficiency of Cu2ZnSn(S,Se)4 Solar Cells by pretreating Mo electrode with H2O2

It is proved that secondary phases, such as Cu2Se, and ZnSe etc., and MoSe2 layer can form at Cu2ZnSn(S,Se)4 (CZTSSe)/Mo electrode interface, due to that Mo electrode reacts with CZTSSe and Se vapor during selenization process. The secondary phases and MoSe2 with inappropriate thickness can decrease power conversion efficiency (PCE) of CZTSSe solar cell. In this work, a simple method was proposed to suppress the reaction between CZTSSe and Mo, and to optimize the thickness of MoSe2. This was achieved by growing a layer of Mo oxide in situ on the Mo electrode surface through soaking the Mo electrode in H2O2. The Mo oxide layer consisted of MoO3, MoOx and MoO2. It could suppress the reaction between Mo and CZTSSe, thus preventing the formation of secondary phases in CZTSSe. By further tuning the soaking time, the thickness and density of the Mo oxide layer were optimized, resulting in an optimized thickness of the MoSe2 layer and a significant improvement in the contact quality at both the front and back interfaces. This improvement is beneficial for suppressing carrier recombination and reducing contact resistance. Furthermore, the Cu/(Zn+Sn) ratio in CZTSSe was optimized, leading to an expansion of the depletion region width. As a result, the reverse saturation current density and series resistance decrease, while the photogenerated current density increases. This ultimately led to a rise in PCE from 7.66% for CZTSSe solar cells with Mo electrodes that were not soaked to 8.95% for those with Mo electrodes soaked for 20 s.

Enhanced Efficiency and Stability of Inverted CsPbI2Br Perovskite Solar Cells via Fluorinated Organic Ammonium Salt Surface Passivation.

All-inorganic perovskite solar cells (PSCs) have recently received increasing attention due to their outstanding thermal stability. However, the performance of these devices, especially for the devices with a p-i-n structure, is still inferior to that of the typical organic-inorganic counterparts. In this study, we introduce phenylammonium iodides with different side groups on the surface of the CsPbI2Br perovskite film and investigate their passivation effects. Our studies indicate that the 4-trifluoromethyl phenylammonium iodide (CFPA) molecule with the -CF3 side group effectively decreases the trap density of the perovskite film by forming interactions with the undercoordinated Pb2+ ions and significantly inhibits the nonradiative recombination in the derived PSC, leading to an enhanced open-circuit voltage (Voc) from 0.96 to 1.10 V after passivation. Also, the CFPA post-treatment enables better energy-level alignment between the conduction band minimum of CsPbI2Br perovskite and [6,6]-phenyl C61 butyric acid methyl ester, thereby enhancing the charge extraction from the perovskite to the charge transport layer. These combined benefits result in a significant enhancement of the power conversion efficiency from 11.22 to 14.37% for inverted CsPbI2Br PSCs. The device without encapsulation exhibits a degradation of only ≈4% after 1992 h in a N2 glovebox.