Improved Power Conversion Efficiency Research Articles

Photonic crystal surface emitting lasers with multiple-junction operating at high order waveguide mode.

We propose a novel design for multi-junction photonic crystal surface emitting lasers (PCSELs) operating in higher-order waveguide modes to minimize internal losses. This paper details the design and simulation of a 2-junction PCSEL, including calculations of confinement factors, coupling coefficients, radiation loss, and threshold currents. We compare the performance of 2J-PCSELs and 1J-PCSELs, demonstrating the potential for highly efficient multi-junction PCSELs with improved power conversion efficiency and output power.

Construction of ultra-smooth and void-free buried interface via bilateral chemical bridging for efficient and hysteresis-suppressed perovskite solar cells

The surface properties are vital aspects in improving photovoltaic performance of perovskite solar cells (PSCs). Except for the upper surface of perovskite, the hidden buried interface which supports the beginning of perovskite film crystallization is of equal great importance for the construction of high-efficiency PSCs. Herein, we use urea phosphate (UPP) to build a bilateral chemical bridge in the buried interface under perovskite layer, to simultaneously improve the properties of SnO2 ETL and the upper perovskite. On one hand, the interaction between UPP and SnO2 passivates the defects of the SnO2 and facilitates the formation of ultra-smooth surface for superior interfacial contact. On the other hand, the chemical interaction between UPP and perovskite contributes to the optimization of crystal nucleation and growth, which improves the crystalline quality of perovskite, inhibits the formation of voids at the buried interface and reduces the defects of the grain boundary. Benefiting from the optimized buried interfacial contact, suppressed defects, accelerated charge extraction and modified energy level alignment, the UPP-processed device delivers an improved power conversion efficiency of 24.54 %, with effective suppression of hysteresis. Moreover, the stability of device is also improved owing to the reduction of trap defects. This work provides a feasible strategy to tune the buried interface between the charge transfer layer and perovskite layer for fabrication of efficient and stable PSCs.

Eco-friendly synthesis of Nd³⁺-doped Eu₂O₃ nanoparticles for enhanced dye-sensitized solar cells utilizing oxalis Corniculata leaf extract

An environmentally friendly synthesis of Nd³⁺-doped Eu₂O₃ nanoparticles (NPs) was developed using Oxalis Corniculata leaf (OCL) extract to enhance the performance of dye-sensitized solar cells (DSSCs). The as-synthesized NPs were annealed at 600 °C to improve their crystallinity. X-ray diffraction and field-emission scanning electron microscopy revealed high crystallinity and a sub-100 nm spherical morphology. Annealing reduced the NP size from ∼85 nm to ∼45 nm and decreased the bandgap from 4.97 eV to 4.62 eV, enhancing low-energy photon absorption. Fourier-transform infrared spectroscopy showed changes in the chemical bonding environment, with a higher presence of dangling bonds in the as-prepared NPs compared to the 600 °C-annealed NPs, likely due to the OCL extract. Photoluminescence spectra confirmed strong red emission peaks at 580 nm and 612 nm, with a slight reduction in the full width at half maximum of the electric dipole transition after annealing. Integrating these NPs into TiO₂ matrices in DSSCs improved power conversion efficiency to 8.58%, outperforming both as-prepared NPs (6.88%) and bare TiO₂ cells (5.05%). This green synthesis approach offers a sustainable pathway for slightly enhancing performance of photovoltaic devices, with additional potential for UV-shielding applications when incorporated into PVA films.

Advancements and Challenges in Antenna Design and Rectifying Circuits for Radio Frequency Energy Harvesting.

The proliferation of smart devices increases the demand for energy-efficient, battery-free technologies essential for sustaining IoT devices in Industry 4.0 and 5G networks, which require zero maintenance and sustainable operation. Integrating radio frequency (RF) energy harvesting with IoT and 5G technologies enables real-time data acquisition, reduces maintenance costs, and enhances productivity, supporting a carbon-free future. This survey reviews the challenges and advancements in RF energy harvesting, focusing on far-field wireless power transfer and powering low-energy devices. It examines miniaturization, circular polarization, fabrication challenges, and efficiency using the metamaterial-inspired antenna, concentrating on improving diode nonlinearity design. This study analyzes key components such as rectifiers, impedance matching networks, and antennas, and evaluates their applications in biomedical and IoT devices. The review concludes with future directions to increase bandwidth, improve power conversion efficiency, and optimize RF energy harvesting system designs.

Enhanced Performance of Close-Spaced Sublimation Processed Antimony Sulfide Solar Cells via Seed-Mediated Growth.

Antimony sulfide (Sb2S3) has attracted much attention due to its great prospect to construct highly efficient, cost-effective, and environment-friendly solar cells. The scalable close-spaced sublimation (CSS) is a well-developed physical deposition method to fabricate thin films for photovoltaics. However, the CSS-processed absorber films typically involve small grain size with high-density grain boundaries (GBs), resulting in severe defects-induced charge-carrier nonradiative recombination and further large open-circuit voltage (VOC) losses. In this work, it is demonstrated that a chemical bath deposited-Sb2S3 seed layer can serve as crystal nuclei and mediate the growth of large-grained, highly compact CSS-processed Sb2S3 films. This seed-mediated Sb2S3 film affords reduced defect density and enhanced charge-carrier transport, which yields an improved power conversion efficiency (PCE) of 4.78% for planar Sb2S3 solar cells. Moreover, the VOC of 0.755V that is obtained is the highest reported thus far for vacuum-based evaporation and sublimation processed Sb2S3 devices. This work demonstrates an effective strategy to deposit high-quality low-defect-density Sb2S3 films via vacuum-based physical methods for optoelectronic applications.

Researching Organic Solar Cells from the Perspective of Literature Big Data Analysis

Solar cell research aims to improve power conversion efficiency (PCE). This field has an extensive body of literature on the Web of Science. For researchers, it is impossible to understand the development of the entire field comprehensively through traditional reading methods. Knowledge is recorded in the literature by text and numbers. Researchers acquire knowledge through literature surveying, text reading, and thinking. The conversion from text and numbers to knowledge can be automatically completed by machines, which can avoid path‐dependent perspectives. In this work, an intelligent machine learning method for literature structure delineation and information extraction is proposed. As an example, a knowledge base of organic solar cells (OSCs) is extracted including topic analysis of literature, numerical characteristics of performance, and material information. Seven major research directions of OSCs are identified. The correlations between key performance parameters, including PCE, short‐circuit current density (JSC), open‐circuit voltage (VOC), and fill factor (FF), are revealed from text mining. A donor–acceptor material map of PCE is constructed which provides a road map for OSCs, indicating the bottleneck of this field. Moreover, the method of machine intelligence developed here can be used in any other materials field, aiding a comprehensive understanding of the development quickly.

Numerical optimization of inorganic p-Sb2Se3/n-ZrS2 heterojunction solar cells: achieving high efficiency through SCAPS-1D simulation

p-Sb2Se3 and n-ZrS2 materials show strong potential for cost-effective photovoltaic applications. This study presents a detailed numerical analysis of p-Sb2Se3/n-ZrS2 heterojunction solar cells using SCAPS-1D, focusing on how key parameters such as layer thickness, doping density, and bandgap have affected device performance. Critical photovoltaic metrics, such as built-in voltage (Vbi), carrier lifetime, depletion width (Wd), recombination rates, and photogenerated current, were examined. Our findings demonstrate that optimizing the p-Sb2Se3 absorber layer with a 1.0 eV bandgap, 5000 nm thickness, and doping density of 1020 cm−3 leads to a maximum efficiency of 32.14%, with a fill factor (FF) of 84.57%, short-circuit current density (Jsc) of 47.61 mA cm−2, and open-circuit voltage (Voc) of 0.792 V. For the ZrS2 buffer layer, the best performance was achieved with a 1.2 eV bandgap, 200 nm thickness, and doping density below 1 × 1020 cm−3. These optimized parameters significantly enhanced carrier separation and minimized recombination losses, leading to improved power conversion efficiency. In addition to theoretical optimization, this study emphasizes the practical potential of these materials for real-world applications. The combination of Sb2Se3 and ZrS2 offers a low-cost fabrication process suitable for scalable commercial solar cell production while maintaining high efficiency. These results underscore the viability of p-Sb2Se3/n-ZrS2 heterojunctions as promising candidates for next-generation clean energy solutions.

Design and Simulation for Minimizing Non-Radiative Recombination Losses in CsGeI2Br Perovskite Solar Cells.

CsGeI2Br-based perovskites, with their favorable band gap and high absorption coefficient, are promising candidates for the development of efficient lead-free perovskite solar cells (PSCs). However, bulk and interfacial carrier non-radiative recombination losses hinder the further improvement of power conversion efficiency and stability in PSCs. To overcome this challenge, the photovoltaic potential of the device is unlocked by optimizing the optical and electronic parameters through rigorous numerical simulation, which include tuning perovskite thickness, bulk defect density, and series and shunt resistance. Additionally, to make the simulation data as realistic as possible, recombination processes, such as Auger recombination, must be considered. In this simulation, when the Auger capture coefficient is increased to 10-29 cm6 s-1, the efficiency drops from 31.62% (without taking Auger recombination into account) to 29.10%. Since Auger recombination is unavoidable in experiments, carrier losses due to Auger recombination should be included in the analysis of the efficiency limit to avoid significantly overestimating the simulated device performance. Therefore, this paper provides valuable insights for designing realistic and efficient lead-free PSCs.

Room-Temperature Ripening Enabled by Hygroscopic Salts for Hole-conductor-Free Printable Perovskite Solar Cells with Efficiency Over 20 .

Solution-processed perovskite films generally possess small grain sizes and high density of grain boundaries, which intensify non-radiative recombination of carriers and limit the power conversion efficiency (PCE) of solar cells. In this study, we report the room-temperature ripening enabled by the synergy of hygroscopic salts and moisture in air for efficient hole-conductor-free printable mesoscopic perovskite solar cells (p-MPSCs). Treating perovskite films with proper hygroscopic salts in damp air induces obvious secondary recrystallization, which coarsens the grains size from hundreds of nanometers to several micrometers. It's proposed that the hygroscopic salt at grain boundaries could absorb moisture and form a complex which could not only serve as mass transfer channel but also assist in the dissolution of perovskite grains. This activates mass transfer between small grains and large grains since they possess different solubilities, and thus ripens the perovskite film. Consequently, p-MPSCs treated with the hygroscopic salt of NH4SCN show an improved power conversion efficiency of 20.13 % from 17.94 %, and maintain >98 % of the initial efficiency under maximum power point tracking at 55±5 °C for 350 hours.

Sputter-deposited TiOx thin film as a buried interface modification layer for efficient and stable perovskite solar cells

Despite perovskite solar cells (PSCs) based on a SnO2 hole-blocking layer (HBL) are achieving excellent performance, the non-perfect buried interface between the SnO2 HBL and the perovskite layer is still an obstacle in achieving further improvement in power conversion efficiency (PCE) and stability. The poor morphology with numerous defects and the energy level mismatch at the buried interface constrain the open circuit voltage and cause instability. Herein, a sputter-deposited TiOx thin film is used as a buried interface modification layer to address the aforementioned issues. Utilizing in situ grazing-incidence small-angle X-ray scattering (GISAXS) during the sputter deposition, we monitor and unveil the growth process of the TiOx thin film, identifying a 10 nm thickness optimum. The defects at the buried interface are passivated through tuning the growth, leading to a suppressed non-radiative recombination and improved PCE (from 22.19 % to 23.93 %). The evolution of the device performance and the degradation process of PSCs using operando grazing-incidence wide-angle X-ray scattering (GIWAXS) under the protocol ISOS-L-1I explains the enhanced stability introduced by the buried interface modification via a sputter-deposited TiOx thin layer. The perovskite decomposition process and the detrimental formation of PbI2 are both slowed down by the TiOx thin layer.

Organic Salt Buffer Layer Enables High‐Performance NiOx‐Based Inverted Perovskite Solar Cells

The merits of a low‐cost fabrication process, suitable band structure, excellent wettability to perovskite precursor, and outstanding stability ensure NiOx as a hole transport material with beneficial characteristics to construct high‐performance perovskite solar cells (PSCs). However, direct contact between perovskite and NiOx causes delamination and chemical instability and thus results in poor carrier transport and short device lifespan. Here, we propose a solution for this issue by introducing an organic salt additive 4‐(trifluoromethyl) benzylammonium formate (TFMBAFa) in the perovskite precursor to passivate perovskite film and NiOx@(2‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl) ethyl) phosphonic acid (Me‐2PACz) composited hole transport layer (HTL), and thus construct a buffer layer between perovskite‐HTL interface. The effective diminishing of NiOx/perovskite interfacial reactions and defects results in enhanced carrier transport. Consequently, the target device achieves simultaneous improvements in power conversion efficiency (24.2%), storage stability (T100 > 1400 h), thermal stability (T80 > 1000 h), and operational stability (T70 > 850 h), where T100, T80, and T70 refer to the retention of 100%, 80%, and 70% of initial PCE, respectively. This work provides an effective strategy to advance the performance of NiOx‐based inverted PSCs.

Loading Precursors into Self‐Assembling Contacts for Improved Performance and Process Control in Evaporated Perovskite Solar Cells

Organo‐lead‐halide perovskites are promising materials for solar cell applications with efficiencies now exceeding 26% for single junction, and over 33% for silicon tandem devices. Evaporation has proven viable for industrial scale‐up but presents challenges for perovskite materials. Perovskite precursor is introduced into self‐assembling MeO‐2PACz hole transport layers for application to 4 source perovskite coevaporation. This allows precursors that can be difficult to add via evaporation, like methylammonium chloride. These precursor molecules influence growth during evaporation, film behavior during annealing as measured by photoluminescence, and aid the conversion to perovskite as shown by X‐Ray diffraction. Devices have improved power conversion efficiency and stability compared to a control sample within the same evaporation. The best cells reach ≈21% efficiency and comparable performing ≈20% cells maintain their original efficiency after 1000 h of maximum power tracking at 25 °C. This process provides significant process flexibility for perovskite evaporation and requires no additional steps.

Incorporation of Gold Nanoparticle into ZnO Electron Transport Layer to Improve Performance of Hybrid Bulk Heterojunction Solar Cell

Abstract We have investigated the effect of localized surface plasmon resonance (LSPR) from gold nanoparticles incorporated into the electron transport layer (ETL) of zinc oxide (ZnO) on charge carrier transport in order to improve the performance of inverted hybrid bulk-heterojunction solar cells. Synthesis of gold nanoparticles capped by 3-mercaptopropionic acid (AuMPA) and oleylamine (AuOA) was carried out by use of the reduction method and the fabrication of solar cell device with the configuration of ITO/ZnO:AuNPs/P3HT:PCBM/PEDOT:PSS/Ag was done by spin coating and thermal evaporation techniques. The absorbance spectra show a plasmonic peak of AuMPA in solution at 521 nm, while AuOA has a plasmonic peak at 531 nm, with both solutions showing a red-wine color. In our investigation, the incorporation of AuMPA about 2.65wt% or AuOA about 3.5 wt% in the ZnAc solution is quite stable. With the addition of 1.77 wt% AuMPA, the fabricated devices show a significant improvement at short circuit condition (JSC) from 46.67 mA/cm2 to 83.11 mA/cm2, resulting in an increase in power conversion efficiency (PCE) from 5.64% to 9.00% under the illumination of 100 mW/cm2 simulated solar irradiation. While the AuOA addition of 2.65 wt%, the JSC increased from 22.67 mA/cm2 to 44.12 mA/cm2 along with an improvement of PCE from 2.71% to 5.32%. The experiment results suggest that the electron mobility or charge carrier transport to the indium tin oxide (ITO) cathode is improved by the local electric field enhancement around the zinc oxide (ZnO) electron transport layer due to the effect of gold nanoparticles (AuNPs).

High-performance CIGS solar cells using a double active layers approach – SCAPS 1D optoelectronic modeling approach

One of the properties of the CIGS solar cell is that it can have an adjustable band gap energy. The band gap varies in the range from 1.01 to 1.7 eV as a function of materials content. Enhancing the bandgap profile of the active layer, which is where the majority of charge carrier photo-generation occurs, should significantly improve cell performance. Superimposing absorber layers with different electrical characteristics is one way of refining the bandgap profile and achieving these results. It is possible to analyze the optoelectronic output properties and simulate this active multilayer approach using a reference cell thanks to the SCAPS numerical modeling tool. Considering this, we have successfully simulated the following structure: CIGS2/CIGS1/SDL/ZnS/ZnO. The SDL which stands for Surface Defect Layer, has been considered for the property discontinuity interface, mainly characterized by the formation of defect states. That enabled to achieve realistic-like device with an improvement of power conversion efficiency (PCE) up to 11.98 %, i.e. 29.22 % and a fill factor (FF) of 82 % employing a total thickness of active layer of 800 nm. All simulations were performed considering experimental environment parameters, an external temperature of 300 K, light illumination of AM1.5G and defects states were assumed in both the bulk and at interfaces.

Enhancing photovoltaic cell design with multilayer sequential neural networks: A study on neodymium-doped ZnO nanoparticles

Multilayer sequential neural networks, a powerful machine learning model, demonstrate the ability to learn intricate relationships between input features and desired outputs. This study focuses on employing such models to design photovoltaic cells. Specifically, neodymium (Nd)-doped ZnO nanoparticles (NPs) were utilized as a photoanode for fabricating dye-sensitized solar cells (DSSCs). A natural dye extracted from Spinacia oleracea was employed, while two types of electrolytes, liquid and gel (polyethylene glycol-based), were used for comparative analysis. Extensive material characterization of the photoanode highlights the impact of Nd content on the physicochemical properties of ZnO. Notably, when the doped photoanode and gel electrolyte were combined, a substantial 110% improvement in power conversion efficiency (PCE) was achieved. Building on these findings, the machine learning model in this research accurately predicts the current-voltage (I-V) curve values for such photoanodes, with an impressive accuracy of 98%. Additionally, the model illuminates the significance of variables like crystal distortion, texture coefficient, and doping concentration, underscoring their importance in the context of photovoltaic cell design.

Revealing Defect Passivation and Charge Extraction by Ultrafast Spectroscopy in Perovskite Solar Cells through a Multifunctional Lewis Base Additive Approach

Defect passivation inside the crystal lattice and the grain‐boundary (GB) surface of the perovskite films has become the most effective strategy to suppress the negative impact of the nonradiative recombination in perovskite solar cell. In this study, a unique approach to effectively passivate the defect states of MAPbI3 perovskite thin film using thionicotinamide (TNM) as a multifunctional Lewis base additive is demonstrated. TNM as an additive with three different types of Lewis base sites, i.e., pyridine, amino, and CS functional groups, is introduced to mitigate the trap states in the TNM‐modified perovskite films and thoroughly investigate the passivation defects. The nonbonded electron of the three different Lewis base sites can synergistically passivate the antisite lead (Pb) defects and improve the stability of the device. In addition, the NH2 group can form ionic bonds with negatively charged I– ions and inhibit ion migration caused by them. It is found that such passivation effect of TNM reduces the GB defects and improves the crystallinity significantly. As a result, a champion TNM‐modified device shows an improved power conversion efficiency of 19.26% from 16.86% along with enhanced open‐circuit voltage, fill factor, and negligible hysteresis.

Tin oxides@stannous pyrophosphate colloidal quantum dots as multifunctional electron transporting layer for efficient and stable perovskite solar cells

Perovskite solar cells (PSCs) are anticipated to spearhead the revolution in solar energy technology. Engineering the electron transporting layer (ETL)/perovskite heterointerface is known to be a key point for further high-performance PSCs because it determines the main charge transporting and energy losses. However, the most advanced SnO2 colloidal precursors tend to exhibit agglomeration and structural flaws, thereby deteriorating the morphology and electronic mass of the obtained ETL. Here, we polished the microstructure of the SnO2 surface by self-assembling SnO2@Sn2P2O7 quantum dots (SPOS), which is synthesized by the chemical reaction between hypophosphoric acid (H3PO2) and SnO2. The Sn2P2O7 was synthesized on the SnO2 surface, terminating the surface dangling bonds and resulting in steady SPOS quantum dots with smooth microstructure. The SPOS ETL with good optical and electrical properties as well as matched bandgap alignment with perovskite, yielding an improved power conversion efficiency of 23.35% for PSCs. Moreover, due to the suppression of defect-induced deprotonation reactions, the SPOS-PSCs exhibit favorablelongstability than the SnO2-PSCs. This work demonstrates that the surface reconstruction of the ETL is crucial for enhancing the power conversion efficiency and stability of PSCs.

A multifunctional interlayer between mesoporous TiO2 and perovskite for perovskite solar cells with high efficiency and stability

The industrialization of the perovskite solar cells (PSCs) requires further lifting their power conversion efficiency (PCE). There are some important factors to hinder the PCE improvement, such as interface defects and energy level mismatching betwee electron transport layer (ETL) and perovskite layer, and solar energy loss due to no absorption of near infrared (NIR) for the perovsktie. Thus in this study, a multifunctional material of W-Er-Yb doped TiO2 (W-UC-TiO2) was prepared and applied to PSCs as an interlayer between mesoporous TiO2 and perovskite. The experimental results demonstrate that the interlayer of W-UC-TiO2 has the functions of improving NIR absorption for PSCs, passivating inerface defects and improving energy level matching between TiO2 and perovskite. A high efficiency of 21.32% was acquired for the PSCs with W-UC-TiO2 interlayer from 19.26% for the control device. Moreover, stability of the PSCs was improved by the insertion of W-UC-TiO2 interlayer.

Minimizing voltage loss for perovskite solar cells via synergistically passivating defects and reinforcing interfacial electric field

Perovskite solar cells have attracted much attention because of their excellent photoelectric properties. However, non-radiative recombination losses due to interface defects limit the open circuit voltage (Voc) of PSCs, which prevents further improvement in power conversion efficiency (PCE). To solve this problem, we introduced Li2SO4 into the SnO2/perovskite interface to obtain a higher Voc through interfacial passivation and enhancement of the interface electric field. Herein, Li+ presents bottom-up diffusion into perovskite surface, and forms dipoles with FA to enhance the interface electric field. Furthermore, SO in SO42- passivates Sn4+ on the surface of SnO2 and Pb2+ at the buried interface of perovskite. This method combines interfacial passivation with synchronous electric field enhancement, which promotes interfacial carrier migration and reduces non-radiative recombination and voltage loss (Vloss) at the interface. As a result, the SLS-device exhibits an enhanced Voc of 1.25 V, with a very low Vloss of 0.33 V, achieving an outstanding PCE of 24.31 %. Moreover, the device maintained 90 % of the initial PCE after exposure to ambient air for 1000 h. This work demonstrates the necessity to co-design the interface microstructure and electric field distribution for reducing the energy loss of perovskite photovoltaic devices and promoting the efficiency of interfacial charge transport.

Amphipathic Astaxanthin Additive for Low Voltage-loss Perovskite Solar Cells With Enhanced Quasi-Fermi Level Splitting and Solar Hydrogen Production Application.

Even though the power conversion efficiency (PCE) of perovskite solar cells (PSCs) is nearly approaching the Schottky-Queisser limit, low open-circuit voltage (Voc) and severe Voc loss problems continue to impede the improvement of PCEs. Astaxanthin (ASTA) additive is introduced in the formamidinium lead triiodide (FAPbI3)perovskite film as an additive, which can facilitate the transportation of charge carriers and interact with Pb2+ by its distinctive groupings. Furthermore, the addition of ASTA decreases the defect's active energy, regulates the deep-level defect by filling up the grain boundaries (GBs), and promotes the crystallization of perovskite film. Remarkably, an enhanced quasi-Fermi level splitting (QFLS) of 1.164eV and a reduced Voc loss of only 96mV are realized. The champion PCE of 24.56% is attained by ASTA-modified PSCs on the basis of 22.75% PCE. Moreover, the PSCs that underwent ASTA modification demonstrate improved operational stability, ensuring consistent output in real-world scenarios. Furthermore, PSCs with an active area of 1 cm2 are used for water electrolysis to produce hydrogen and exhibit a PCE of 22.41%. This work offers an environmentally benign solution to address the inherent issues of FAPbI3 PSCs and lays the groundwork for the development of a prospective solar hydrogen production application.