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Visible light driven photoelectrocatalysis on a FTO/BiVO4/BiOI anode for water treatment involving emerging pharmaceutical pollutants
摘要： Contamination of water bodies by harmful and recalcitrant organic substances is a global challenge. A promising technique for removing these organics from water/wastewater is photoelectrocatalytic oxidation which combines electrolytic and photocatalytic processes. Herein, we report the degradation of emerging pharmaceutical pollutants e acetaminophen and cipro?oxacin e at a BiVO4/BiOI photoanode under visible irradiation via photoelectrocatalytic process. The BiVO4/BiOI was electrodeposited on a FTO glass and characterised with XRD, SEM, EDS and diffusive re?ectance UVeVis. The results con?rmed the successful electrodeposition of BiVO4/BiOI on the glass substrate. Mott-Schotty plots con?rmed the formation of p-n heterojunction between the two electrodeposited semiconductors. The calculated charge carrier density of BiVO4/BiOI was higher than those of pristine BiVO4 and BiOI. The binary electrode also gave improved photocurrent response compared with unitary electrodes. Degradation ef?ciencies of 68% and 62% were achieved upon the application of the prepared photoanode (FTO/BiVO4/BiOI) in PEC degradation of acetaminophen and cipro?oxacin respectively using a bias potential of 1.5 V within 2 h. A synthetic pharmaceutical wastewater containing a mixture acetaminophen and cipro?oxacin was also treated with the photoanode. The photoanode was also effective in the degradation of dye. The ?ndings of this study suggest the suitability of the prepared photoanode for the photoelectrocatalytic degradation of organic pharmaceutical pollutants in wastewater.
关键词： Cipro?oxacin,p-n heterojunction photoanode,Photoelectrocatalytic degradation,Bismuth oxyiodide,Acetaminophen,Bismuth vanadate
更新于2025-11-14 14:48:53
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Effects of fluorination and thermal annealing on charge recombination processes in polymer bulk-heterojunction solar cells
摘要： We investigate the effect of fluorination on the photovoltaic properties of an alternating conjugated polymer composed of 4,8-di-2-thienylbenzo[1,2-b:4,5-b0]dithiophene and 4,7-bis([2,20-bithiophen]-5-yl)-benzo-2-1-3-thiadiazole (4TBT) units in bulk-heterojunction solar cells. The unsubstituted and fluorinated polymers afford very similar open-circuit voltages and fill factor values, but the fluorinated polymer performed better due to enhanced aggregation which provides a higher photocurrent. The photovoltaic performance of both materials improved upon thermal annealing at 150–200 °C as a result of a significantly increased fill factor and open-circuit voltage, counteracted by a slight loss in photocurrent. Detailed studies of the morphology, light intensity dependence, external quantum efficiency and electroluminescence allowed the exploration of the effects of fluorination and thermal annealing on the charge recombination and the nature of the donor–acceptor interfacial charge transfer states in these films.
关键词： polymer bulk-heterojunction solar cells,thermal annealing,charge recombination,fluorination,photovoltaic properties
更新于2025-10-22 19:40:53
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Effect of front TCO on the performance of rear-junction silicon heterojunction solar cells: Insights from simulations and experiments
摘要： In this study we make a detailed comparison between indium tin oxide (ITO), aluminum-doped zinc oxide (ZnO:Al) and hydrogenated indium oxide (IO:H) when applied on the illuminated side of rear-junction silicon heterojunction (SHJ) solar cells. ITO being the state of the art material for this application, ZnO:Al being an attractive substitute due to its cost effectiveness and IO:H being a transparent conductive oxide (TCO) with high-mobility and excellent optical properties. Through numerical simulations, the optically optimal thicknesses for a double layer anti-reflective coating system, consisting of the respective TCO and amorphous silicon oxide (a-SiO2) capping layers are defined. Through two-dimensional electrical simulations, we present a comparison between front-junction and rear-junction devices to show the behavior of series resistance (Rs) in dependence of the TCO sheet resistance (Rsh) and the device effective lifetime (τeff). The study indicates that there is a τeff dependent critical TCO Rsh value, above which, the rear-junction device will become advantageous over the front-junction design in terms of Rs. Solar cells with the respective layers are analyzed. We show that a thinner TCO optimized layer will result in a benefit in cell performance when implementing a double layer anti-reflective coating. We conclude that for a highest efficiency solar cell performance, a high mobility TCO, like IO:H, is required as the device simulations show. However, the rear-junction solar cell design permits the implementation of a lower conductive TCO in the example of the cost-effective ZnO:Al with comparable performance to the ITO, opening the possibility for substitution in mass production.
关键词： Transparent conductive oxide,Sheet resistance,Series resistance,Rear-junction,Silicon heterojunction,Anti-reflective coating
更新于2025-10-22 19:40:53
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Photocatalytic performance of TiO2 thin film decorated with Cu2O nanoparticles by laser ablation
摘要： Cu2O nanoparticles decorated TiO2 thin films were fabricated by laser ablation. The effects of Cu2O nanoparticles on the structure, optical properties and photocatalytic performance of TiO2 thin film were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectrometer system, optical absorption and photocatalytic evaluation system, respectively. XRD patterns indicate that the decoration has the effect of lowering the grain orientation of Cu2O. The photocatalytic performance in hydrogen generation of Cu2O decorated TiO2 composite thin film was significantly improved compared with that of either Cu2O nanoparticles or TiO2 single layer thin film with 1.70 and 1.77 times, respectively. The oxidation of Cu2O was demonstrated to dominate the photocatalytic performances of Cu2O/TiO2 composite thin films by varying the laser ablation powers.
关键词： Heterojunction,Cu2O nanoparticles,Laser ablation,Photocatalytic performance,TiO2 thin film
更新于2025-10-22 19:40:53
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Advanced Graphene-Based Transparent Conductive Electrodes for Photovoltaic Applications
摘要： New architectures of transparent conductive electrodes (TCEs) incorporating graphene monolayers in different configurations have been explored with the aim to improve the performance of silicon-heterojunction (SHJ) cell front transparent contacts. In SHJ technology, front electrodes play an important additional role as anti-reflectance (AR) coatings. In this work, different transparent-conductive-oxide (TCO) thin films have been combined with graphene monolayers in different configurations, yielding advanced transparent electrodes specifically designed to minimize surface reflection over a wide range of wavelengths and angles of incidence and to improve electrical performance. A preliminary analysis reveals a strong dependence of the optoelectronic properties of the TCEs on (i) the order in which the different thin films are deposited or the graphene is transferred and (ii) the specific TCO material used. The results shows a clear electrical improvement when three graphene monolayers are placed on top on 80-nm-thick ITO thin film. This optimum TCE presents sheet resistances as low as 55 ?/sq and an average conductance as high as 13.12 mS. In addition, the spectral reflectance of this TCE also shows an important reduction in its weighted reflectance value of 2–3%. Hence, the work undergone so far clearly suggests the possibility to noticeably improve transparent electrodes with this approach and therefore to further enhance silicon-heterojunction cell performance. These results achieved so far clearly open the possibility to noticeably improve TCEs and therefore to further enhance SHJ contact-technology performance.
关键词： transparent electrodes,silicon heterojunction solar devices,graphene
更新于2025-10-22 19:40:53
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CuInS2 sensitized TiO2 for enhanced photodegradation and hydrogen production
摘要： A novel CuInS2/TiO2 (CIS-TO) heterojunction which displayed two different transfer pathways of photo-generated carries under UV–vis and Vis light irradiation was fabricated through a facile in-situ growth method. Under vis-light (λ ≥ 420 nm) excitation, 97.37% RhB (10 mg/L) was photodegraded with 20 mg of 1% CIS-TO photocatalyst within 90 min, and the degradation constant could up to 0.0415 min?1, which was about 8.28 times to pure TiO2 (0.00501 min?1) and the typical heterojunction was formed between CuInS2 and TiO2 to provide the photo-electrons transfer channel. Under UV–vis light irradiation, a Z-scheme heterojunction was formed to provide another highly effective electron transfer channel for hydrogen production and the hydrogen production rate could reach 785.4 μmol g?1 h?1 with 1% CIS-TO photocatalyst, which showed nearly 1.68 times than that of pure TiO2. The enhanced photocatalytic activity could be attributed to the synergistic effect of the sensitization and narrow band gap of CuInS2 which could effectively broaden the spectral response range, enhance the photon utilization and inhibit the recombination of photogenerated electrons and holes. Additionally, the high stability of the material was illustrated by the cycle experiments of photodegradation and hydrogen production.
关键词： Typical heterojunction,Sensitization,Z-scheme heterojunction,Photodegradation,CuInS2/TiO2
更新于2025-09-23 15:23:52
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2D Material-Based Vertical Double Heterojunction Bipolar Transistors with High Current Amplification
摘要： The heterojunction bipolar transistor (HBT) differs from the classical homojunction bipolar junction transistor in that each emitter-base-collector layer is composed of a different semiconductor material. 2D material (2DM)-based heterojunctions have attracted attention because of their wide range of fundamental physical and electrical properties. Moreover, strain-free heterostructures formed by van der Waals interaction allows true bandgap engineering regardless of the lattice constant mismatch. These characteristics make it possible to fabricate high-performance heterojunction devices such as HBTs, which have been difficult to implement in conventional epitaxy. Herein, NPN double HBTs (DHBTs) are constructed from vertically stacked 2DMs (n-MoS2/p-WSe2/n-MoS2) using dry transfer technique. The formation of the two P–N junctions, base-emitter, and base-collector junctions, in DHBTs, was experimentally observed. These NPN DHBTs composed of 2DMs showed excellent electrical characteristics with highly amplified current modulation. These results are expected to extend the application field of heterojunction electronic devices based on various 2DMs.
关键词： 2D materials,tungsten diselenide,P–N junction,heterojunction bipolar transistor,molybdenum disulfide
更新于2025-09-23 15:23:52
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Z-Scheme 2D/2D Heterojunction of Black Phosphorus/Monolayer Bi2WO6 Nanosheets with Enhanced Photocatalytic Activities
摘要： Black phosphorus (BP), a star-shaped two-dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Herein, we design and fabricate a Z-Scheme heterojunction of 2D/2D BP/monolayer Bi2WO6 (MBWO) by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g-1, is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67%. A Z-Scheme photocatalytic mechanism is proposed based on monitoring of ?O2?, ?OH, NO2, and NO3? species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
关键词： hydrogen production,photocatalytic,Black phosphorus,2D/2D heterojunction,Z-Scheme
更新于2025-09-23 15:23:52
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Full spectrum responsive In2.77S4/WS2 p-n heterojunction as an efficient photocatalyst for Cr(VI) reduction and tetracycline oxidation
摘要： In the present work, wrinkled n-type WS2 nanosheets were synthesized and then used to construct the In2.77S4/WS2 p-n heterojunction photocatalyst. Experimental results reveal that the as-prepared hybrids present excellent photocatalytic activity for Cr(VI) reduction and tetracycline oxidation under visible and infrared light irritation. The photocatalytic efficiency of the as-prepared catalysts is found to increase initially followed by the decrease with the more weight content of WS2. When WS2 is up to 4 wt%, the as-prepared photocatalysts exhibit the highest photocatalytic activity, and are capable of reducing 99.1 % of Cr(VI) in 60 min and oxidizing 87.5 % of tetracycline in 20 min, much higher than 86.6 and 40.0 % of pure In2.77S4, respectively. This enhanced photocatalytic activity is attributed to the construction of In2.77S4/WS2 p-n heterojunction between p-In2.77S4 and n-WS2. The detailed clarification of photocatalytic mechanism is also elaborated in the paper.
关键词： In2.77S4,photocatalysis,heterojunction,WS2
更新于2025-09-23 15:23:52
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In situ synthesis of visible-light-driven Z-scheme AgI/Bi2WO6 heterojunction photocatalysts with enhanced photocatalytic activity
摘要： In this work, an efficient visible-light-response AgI/Bi2WO6 heterojunction was successfully prepared via in situ precipitation of AgI nanoparticles on the aligned nanosheets of three-dimensional Bi2WO6 hierarchical microspheres for the first time. Studies suggested that the AgI/Bi2WO6 heterojunction exhibited excellent photocatalytic activity for tetracycline (TC) degradation compared to pure Bi2WO6 and AgI under visible light irradiation. Doping 20 wt% AgI resulted in the optimal TC photodegradation rate, which was 5.4 and 3.3 times higher than pure Bi2WO6 and AgI, respectively. The high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) verified that Ag nanoparticles generated on AgI/Bi2WO6 heterojunction surface in photocatalytic degradation process, which was beneficial for promoting the rapid combination of electrons on the conduction band of Bi2WO6 with the holes on the valence band of AgI and the separation and transfer of photogenerated electron-hole pairs. Accordingly, the nontraditional transport pathway of photogenerated electrons and holes based on the Z-scheme system that consisted of Bi2WO6, AgI, and Ag was confirmed. Based on the systematic experimental evidence, the possible enhanced photocatalytic mechanism was proposed.
关键词： Z-scheme,Photocatalysis,Heterojunction,AgI/Bi2WO6,Tetracycline
更新于2025-09-23 15:23:52