High Photoelectric Conversion Efficiency Research Articles

Controllable Fabrication of Silicon Solar Cells with Inverted or Upright Pyramid Structures by a One-Step Copper Catalysis Method

Abstract Silicon has garnered significant attention as the primary material for solar cell preparation. Traditional alkaline etching solutions are limited to creating an upright pyramid structure on monocrystalline silicon surfaces. However, research indicates that an inverted pyramid structure exhibits superior light-trapping properties compared to the upright pyramid structure. In this study, we employed a one-step copper ion metal-assisted chemical etching process to fabricate an inverted pyramid structure on monocrystalline silicon wafers. This method allows for the customization of either inverted or upright pyramid structures by adjusting the concentration of specific solution components. Characterization of the textured silicon wafers reveals that the inverted pyramid structure exhibits lower reflectivity than both the upright pyramid structure and polished silicon. By integrating this texturing technique into the solar cell production line, we successfully produced solar cells with both inverted and upright pyramid structures. Evaluation of various solar cell parameters demonstrates that the inverted pyramid structure outperforms the upright pyramid structure, showcasing lower reflectivity and higher photoelectric conversion efficiency.

Perovskite materials advance the potent sensor exploration

AbstractPerovskite materials with unique crystal structure have developed rapidly in recent years owing to their special physical and chemical properties, such as high light absorption and extraordinary electrocatalytic properties. Metal halide perovskites are quite attractive in various fields because of their simple manufacturing process, adjustable band gap, good charge transfer performance, and high theoretical photoelectric conversion efficiency. Therefore, perovskite oxides mixed with metal elements become ideal samples for studying the surface and catalytic performance of catalysts. In this review, various metal perovskites are clearly classified and introduced according to the corresponding synthesis methods, including hydrothermal method, sol–gel method, and high‐temperature solid phase, as well as coprecipitation. The excellent properties of perovskite make it extensively used in nanotechnology, chemistry, environmental protection, and material science, especially in solar cells and sensors. In particular, the nanosized perovskite materials are becoming more and more popular in sensors, which was reviewed in detail here. Most importantly, the design of electrochemical sensors using perovskite nanomaterials with low detection limit and high sensitivity will bring new insight into the detection of biomolecules. Both challenges and prospects of metal perovskites were discussed for promoting the development of biosensors in the end.

Effect of Asymmetric InAlGaN/GaN Superlattice Barrier Structure on the Optoelectronic Performance of GaN-Based Green Laser Diode

An asymmetric InAlGaN/GaN superlattice barrier structure without the first quantum barrier layer (FQB) is designed, and its effect on the optoelectronic performance of GaN-based green laser diode (LD) has been investigated based on simulation experiment and analytical results. It is found that, compared with conventional GaN barrier LD, device performance is significantly improved by using FQB-free asymmetric InAlGaN/GaN superlattice barrier structure, including low threshold current, high output power, and high photoelectric conversion efficiency. The threshold current of LD with novel structure is 16.19 mA, which is 22.46% less than GaN barrier LD. Meanwhile, the output power is 110.69 mW at an injection current of 120 mA, which is 16.20% higher compared to conventional LD, and the wall-plug efficiency has an enhancement of 9.5%, reaching 20.27%. FQB-free asymmetric InAlGaN/GaN superlattice barrier layer can reduce optical loss, suppress the polarization effect, and improve the carrier injection efficiency, which is beneficial to improve output power and photoelectric conversion efficiency. The novel epitaxial structure provides theoretical guidance and data support for improving the optoelectronic performance of GaN-based green LD.

Highly Efficient and Stable Perovskite Solar Cell with Sodium Glycine Additive

Organic halide perovskite solar cells (PSCs) with high photoelectric conversion efficiency (PCE) and low manufacturing cost have been attracting considerable attention. However, defects in perovskite as recombination centers and ion migration paths seriously deteriorate the optoelectronic performance of the devices. Herein, a facile strategy is devised by introducing sodium glycinate (SG) mulit-functional additive into perovskite to passivate defects. In this way, the typical defects of mismatched leads in perovskite can be passivated by forming ionic bond with carboxylate radical or coordination bond with amino groups of SG. Also, the SG molecules with cross-linking function could improve the grain size of perovskite to reduce defects and increase light absorption. Besides, sodium ions of SG can impede the ion migration in perovskite and strengthen the interfacial charge transfer ability. As a result, the PSCs assembled under air condition with SG additive achieved a champion efficiency of 19.32% due to the comprehensive action of SG, and an improved stability under work and storage conditions. This provides an economical and effective strategy for the industrialization of PSCs.

Bifacial silicon heterojunction solar cells using transparent‐conductive‐oxide‐ and dopant‐free electron‐selective contacts

AbstractThe development of transparent electron‐selective contacts for dopant‐free carrier‐selective crystalline silicon (c‐Si) heterojunction (SHJ) solar cells plays an important role in achieving high short‐circuit current density (JSC) and consequently high photoelectric conversion efficiencies (PCEs). This becomes even more important when focusing on the development of bifacial solar cells. In this study, bifacial SHJ solar cells using a transparent‐conductive‐oxide‐free and dopant‐free electron‐selective passivating contacts are developed, showing a JSC bifaciality of up to 97%. Intrinsic ZnOX layer deposited by atomic layer deposition was used in this structure, which simultaneously provides negligible passivation loss after annealing and enables a low contact resistivity on the electron‐selective contact. With both side finger metal electrodes contact, this bifacial solar cell shows an efficiency of 21.2% under front‐side irradiation and 20.4% under rear‐side irradiation, resulting in an estimated output power density of 24.1 mW/cm2 when considering rear‐side irradiance of 0.15 sun.

Sulfonic Acid Functionalized Ionic Liquids for Defect Passivation via Molecular Interactions for High-Quality Perovskite Films and Stable Solar Cells.

The high photoelectric conversion efficiency and low cost of perovskite solar cells (PSCs) have further inspired people's determination to push this technology toward industrialization. The high-quality perovskite films and high-efficiency and stable PSCs are the crucial factors. Ionic liquids have been proven to be an effective strategy for regulating high-quality perovskite films and high-performance PSCs. However, the regulation mechanism between ionic liquids and perovskites still needs further clarification. In this study, a novel sulfonic acid-functionalized ionic liquid, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BSO3HMImOTf), was used as an effective additive to regulate high-quality perovskite films and high-performance devices. Microscopic mechanism studies revealed strong interactions between BSO3HMImOTf and Pb2+ ions as well as halogens in the perovskite. The perovskite film is effectively passivated with the controlled crystal growth, suppressed ion migration, facilitating to the greatly improved photovoltaic performance, and superior long-term stability. This article reveals the regulatory mechanism of sulfonic acid type ionic liquids through testing characterization and mechanism analysis, providing a new approach for the preparation of high-quality perovskite devices.

Research progress of magnetic TiO2 photocatalyst in wastewater treatment

ABSTRACT TiO2 photocatalyst has the advantages of high catalytic activity, suitable energy band potential, high chemical stability, high photoelectric conversion efficiency, high safety and non-toxicity, which exhibits excellent performances in photocatalytic degradation of organic wastewater. However, it is difficult to separate and recover TiO2 photocatalyst from the reactive system. Interestingly, magnetic TiO2 prepared by combining TiO2 with superparamagnetic ferromagnetic particles can overcome this shortcoming. In this review, the preparation method and the photocatalytic mechanism of magnetic TiO2 were summarized. Moreover, the catalytic mechanisms of the modified binary, ternary and multicomponent magnetic TiO2 composite photocatalysts were compared, and the effects of different magnetic substrates on the degradation activity were discussed. Besides the applications in the wastewater treatment, the development trend and application prospects were prospected.

Intrinsic pentagon defect engineering in multiple spatial-scale carbon frameworks for efficient triiodide reduction

Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials. However, the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task. Herein, the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations. To experimentally verify this, the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration (CQDs-P), subsequently utilizing CQDs-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide (rGO) via π-π interactions. The multiple spatial-scale rGO-conjugated CQDs-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-ordered π electron delocalization system as conductive network. The defects-rich CQDs-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%, superior to the Pt reference (7.97%). Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates, thus enhancing the electrocatalytic activity of the catalyst. This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.

Theoretical exploration of ternary nitrides for high-efficiency ferroelectric photovoltaics

Although nitride materials hold great functional promise, ferroelectric photovoltaic nitrides remain relatively rare within the scientific community. In this study, high-throughput calculations have been employed to explore and predict novel stable ternary nitrides characterized by both high photoelectric conversion efficiency and robust ferroelectric polarization. Notable candidates, including Mg2CrN3, Mg2MnN3, MgVN2, ZnVN2, and X2BiN3 (where X represents Mg, Ca, and Sr), are anticipated to exhibit remarkable ferroelectric photovoltaic properties, with a particular emphasis on efficiently harnessing visible light. The incorporation of early 3d transition metals and bismuth (Bi) elements within ternary metal nitrides is highlighted as a key strategy for achieving high ferroelectric photovoltaic efficiency. Furthermore, these ferroelectric nitrides demonstrate relatively high carrier mobilities, which are conducive to facilitating the transport of photogenerated carriers driven by ferroelectricity. This research offers a selection of promising ternary nitride candidates with substantial potential for application in the field of ferroelectric photovoltaics.

Facile sulfur-assisted synthesis of GaAs nanowires /si heterojunctions for broadband self-powered photodetector

Nanowires (NWs)-based heterojunction photodetectors (PDs) have been widely applied in the fields of remote sensing, night vision, environmental monitoring, and optical communications with high light absorption coefficient and photoelectric conversion efficiency. Here, S-GaAs NWs/Si heterojunction was developed to form a broadband self-powered PDs by growing GaAs NWs on Si substrate through the sulfur-catalyzed assisted chemical vapor deposition (CVD) technology. Compared with the pure GaAs NWs, the sulfur-assisted catalysts could not only inhibit Ostwald ripening of Au seeds to improve the crystalline quality of NWs but also form a thin Ga–S bond passivation layer to reduce surface defects and enhance the optoelectronic performance of the PDs. The fabricated GaAs NWs/Si heterojunction PDs exhibit excellent performances with the large responsivity of 10.3 mA W−1 and high detectivity of 9.59 × 1012 cm Hz1/2 W−1. Additionally, the designed PDs have the broadband wavelength photoresponse from visible to near infrared and fast response speed (rise/fall time of 3.8/21.8 ms). Importantly, the develop strategy of hybrid heterojunction PDs can be extended to other semiconductor materials for facilitating the practical application of high-performance optoelectronic devices.

Reduced Surface Trap States of PbS Quantum Dots by Acetonitrile Treatment for Efficient SnO2-Based PbS Quantum Dot Solar Cells.

The solution-phase ligand-exchange strategy offers a simple pathway to prepare PbS quantum dots (QDs) and their corresponding solar cells. However, the production of high-quality PbS QDs with reduced surface trap state density for efficient PbS QD solar cells (QDSCs) still faces challenges. As the hydroxyl group (-OH) has been demonstrated to be the primary source of the surface trap states on PbS QDs in the general oleic acid method, here, we present an effective and facile strategy for reducing the surface -OH content of PbS QDs by using acetonitrile (ACN) as precipitant to wash the surface of QDs, which significantly decreases the trap state density and enables the preparation of superior PbS QDs. The resulting solar cell with an ITO/SnO2/n-PbS/p-PbS/Au structure obtained an improved photoelectric conversion efficiency (PCE) from 8.53 to 10.49% with an enhanced air storage stability, realizing a high PCE for SnO2-based PbS QDSCs.

Solution-processed organic-inorganic hybrid material based on P3HT and SnS2 nanoparticles layers: Synthesis and properties

Sn-based nanocomposites attract extensive attention as a new generation of photoelectric hybrid materials due to their high photoelectric conversion efficiency. In this work we synthesized SnS2 nanoparticles by a hydrothermal method employing citric acid (capping agent) and performed a capping agent exchange by pyridine to improve their solution processing and final properties. We fabricated layers with pyridine-capped nanoparticles and poly(3-hexylthiophene-2,5-diyl) (P3HT), employing the classical partial film sequence of a solar cell (ITO/PEDOT:PSS/P3HT:Nps). We found a “coupling" between the nanoparticles and the polymer and highly ordered structures within the layers. The addition of nanoparticles improved the UV–vis absorption of P3HT and allowed the exploitation of the photoluminescence emission to promote extra charge carrier generation. Moreover, we found that SnS2_py nanoparticles form a nanoscopic mixture with the P3HT. Our pyridine-capped SnS2 nanoparticles are good candidates for fabricating hybrid materials, employing P3HT as the organic compound for application in polymeric-inorganic solar cells.

Hole‐Transporting Materials with Rational Combination of Pyridine and Dibenzo[a,c]phenazine as Electron Acceptor for Dopant‐Free Perovskite Solar Cells†

Comprehensive SummaryPerovskite solar cells (PSCs) have been proven to be a promising option for photovoltaic conversion. With the aim to achieve efficient and stable PSCs, it is essential to explore dopant‐free hole‐transporting materials (HTMs) with high hole mobility. Herein, HTMs bearing electron donor (D)‐electron acceptor (A)‐electron donor (D) structures have been constructed with strong intramolecular charge transfer (ICT) effect, based on rational combination of dibenzo[a,c]phenazine and pyridine as electronic acceptors and anchoring groups to perovskite layer. Accordingly, high hole mobility (7.31 × 10–5 cm2·V–1·s–1) and photoelectric conversion efficiency (20.45%) have been achieved by dopant‐free DPyP‐based PSC. It afforded an efficient way to design HTMs with high hole mobility by adjustment of molecular configurations and electronic property of conjugated systems.

Remote Control and Noninvasive Detection Enabled by a High-performance NIR pc-LED.

In an increasing manner, near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are considered to be exemplary light sources owing to their notable attributes of elevated output power, economical nature, and exceptional portability. NIR phosphors are critical components of NIR pc-LEDs. Herein, we report a novel blue light excitable NIR phosphor CaLu2ZrScAl3O12:Cr3+ (CLZSA:Cr3+) as a crucial and efficient broadband NIR emitter. The CLZSA:Cr3+ phosphor displays an intense NIR broadband emission peaking at 776 nm and with a full width at half-maximum (fwhm) of 140 nm. The designed material also exhibits superior resistance to thermal quenching, as the intensity of emission at 423 K remains at 80% of that at room temperature. The constructed NIR pc-LED device based on CLZSA:Cr3+ demonstrates a high total output power of 68.4 mW at a drive current of 100 mA, along with a high photoelectric conversion efficiency of 23.0%. Impressively, the high-power NIR pc-LEDs are utilized as light sources for remote control and non-invasive detection, resulting in the excellent performance and remarkable achievement.

Effect of Silver Powder Microstructure on the Performance of Silver Powder and Front-Side Solar Silver Paste.

Silver powder, as the primary component of solar silver paste, significantly influences various aspects of the paste's performance, including printing, sintering, and conductivity. This study reveals that, beyond the shape and size of the silver powders, their microstructure is a critical factor influencing the performance of both silver powders and silver pastes in solar cell applications. The growth process leads to the formation of either polycrystalline aggregated silver powder or crystal growth silver powder. Analyzing the performance characteristics of these different microstructures provides guidance for selecting silver powders for silver pastes at different sintering temperatures. Polycrystalline aggregated silver powder exhibits higher sintering activity, with a sintering initiation temperature around 450 °C. The resulting silver paste, sintered at 750 °C, demonstrates a low sheet resistance of 2.92 mΩ/sq and high adhesion of 2.13 N. This silver powder is suitable for formulating silver pastes with lower sintering temperatures. The solar cell electrode grid lines have a high aspect ratio of 0.37, showing poor uniformity. However, due to the high sintering activity of the silver powder, the glass layer dissolves and deposits more silver, resulting in excellent conductivity, a low contact resistance of the silver electrode, a low series resistance of the solar cell of 1.23 mΩ, and a high photoelectric conversion efficiency of 23.16%. Crystal growth silver powder exhibits the highest tap density of 5.52 g/cm3. The corresponding silver paste shows improved densification upon sintering, especially at 840 °C, yielding a sheet resistance of 2.56 mΩ/sq and adhesion of 3.05 N. This silver powder is suitable for formulating silver pastes with higher sintering temperatures. The solar cell electrode grid lines are uniform with the highest aspect ratio of 0.40, resulting in a smaller shading area, a high fill factor of 81.59%, and a slightly higher photoelectric conversion efficiency of 23.17% compared to the polycrystalline aggregated silver powder.

Seeking environmentally friendly halide perovskite photocatalysts: synthesis, structure and photocatalytic performance exploration.

Halide perovskites have high photoelectric conversion efficiency, making them promising candidates for photocatalysis. However, their toxic and unstable nature limits their applications. Here, we successfully synthesised three hybrid Bi-based halide perovskites: (HTMG)3Bi2Br9 (1), (HEI)2BiBr5 (2) and (HTMA)3Bi2Br9 (3). X-ray single-crystal diffraction analysis shows that they all contained 0D structures composed of isolated Bi-Br clusters. The three compounds showed excellent degradability and cycling stability for Sudan III dissolved in ethanol under simulated sunlight. In addition, the photocatalytic degradation performance of four Bi-based halide perovskites previously reported by our group is also characterised and summarised in this work.

Simulation of displacement damage of InP induced by protons and α-particles in low Earth orbit

Indium phosphide (InP) material hasmany advantages, such as large band gap, high electron mobility, high photoelectric conversion efficiency, high temperature resistance, and radiation resistance, which is superior to silicon (Si) and gallium arsenide (GaAs). Meanwhile InP is widely used in optical communication, high-frequency millimeter waves, optoelectronic integrated circuits, satellite communication, space solar cells, and other fields. Radiation particles incident on InP device can generate displacement atoms inside the device through elastic processes. And these displacement atoms continue cascade collisions to generate lattice defects which are vacancies, interstitials, and clusters. These defects capture electrons-holes by defective energy levels in the energy band, and then resulting in a decrease in the life of minority carriers which is the reason of degradation of InP devices. The process of degradation of InP device, induced by lattice defects from ion-irradiation, is called displacement damage effect (DDE). The non-ionizing loss energy (NIEL) scaling is a useful method to predict the degradation of device caused by DDE of radiation particles. Many studies have shown that the NIEL is linearly related to the damage coefficient of InP device. Previous studies of radiation damage effect of InP device mainly focused on single-energy protons, electrons, and neutrons. Of the particles in low earth orbit (LEO),the vast majority of particles are protons, with a few being α particles and electrons, while the electron’s NIEL is too small and its DDE is negligible. The InP’s NIEL induced by proton and α energy in LEO has not been studied in detail. Therefore, this paper uses Monte Carlo software Geant4 to study the NIEL, damage energy distribution with depth, and annual total non-ionization loss energy generated by protons and α particles in LEO in 500/1000/5000 μm InP materials. The shielding of 150-μm-thick SiO<sub>2</sub> layer and 2.54-mm-thick Al layer from protons and α particles are used as InP solar cell and InP devices in spacecraft, respectively. It is found that the energy spectrum determines the non-ionizing damage energy <inline-formula><tex-math id="M1">\begin{document}$ {T}_{\text{dam}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231499_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231499_M1.png"/></alternatives></inline-formula> distribution, and then influences the NIEL value: the NIEL value increases with <inline-formula><tex-math id="M2">\begin{document}$ {T}_{\text{dam}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231499_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231499_M2.png"/></alternatives></inline-formula> increasing and thickness of InP material decreasing. And α NIEL is larger than proton’s, the single particle DDE of InP device, induced by α particles, should be concerned. The annual non-ionizing damage energy of proton accounts for 98%, which means that proton is the main factor degrading InP devices in LEO.

A ZnO&GeSe composite electron transport layer for organic solar cells

The deposition of 2D GeSe on the surface of ZnO improves the surface stability of ZnO and reduces the probability of forming defect vacancies on the surface of ZnO, thereby achieving high photoelectric conversion efficiency.

Measures to Improve the Stability of Perovskite Solar Cells

Perovskite materials are considered to be the ideal materials in solar cell production because of their excellent natures, which have received a wide attention. Perovskite solar cell (PSC) is expected to replace the silicon-based solar cell and become the new generation of solar cell technology, because of its low cost, simple process flow and high photoelectric conversion efficiency (PCE). However, the stability of the PSC has been restricting its commercial development. In recent years, much research has been carried out to improve its stability. This review describes the construction of perovskite material, the composition of PSC and the key factors affecting the stability of PSC, including humidity stability, temperature stability and light stability, then takes inorganic buffer layer, ionic liquids and cation doping three methods as examples to summarize the mechanisms and strategies of improving the stability of PSC, and points out the great potential of multi-functional ionic liquids to improve the stability and efficiency of PSC in future.

Principles, development, and utilization of silicon-based solar cell

Photovoltaic technology is a technology that uses the photoelectric conversion properties of semiconductor materials to convert solar energy into electricity. Photovoltaic technology is a kind of renewable energy technology that does not produce pollution and greenhouse gas emissions and has many application prospects. According to data, from 1985 to 2017, the cumulative total installed photovoltaic capacity globally exceeded 400 GW and is expected to grow in the next few years. Photovoltaic technology has become an essential part of renewable energy worldwide. Photovoltaic cells are the core equipment of photovoltaic technology. There are mainly monocrystalline silicon, polysilicon, amorphous silicon, organic solar cells, and other types. Among them, monocrystalline silicon photovoltaic cells have high photoelectric conversion efficiency, but high cost, mainly used in high-end applications; Polysilicon photovoltaic cells are cost-effective and used primarily in large-scale photovoltaic power station construction; Photovoltaic technology can also be used in mobile chargers, solar streetlights, solar pumps, and other aspects. In addition, photovoltaic technology also has a wide range of application prospects in urban rail transit, automobiles, robots, and other fields also appear. Although photovoltaic technology has many advantages, there are still some problems, such as panel cost, reliability, stability, and storage of photovoltaic power generation. Solving these problems requires continuous upgrading and development of technology. With the progress of technology and the support of policies, it is believed that photovoltaic technology will continue to develop and make more significant contributions to global energy transformation and sustainable development.