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Keshavarzi, R. ,
Hajisharifi, F. ,
Saki, Z. ,
Omrani, M. ,
Sheibani, R. ,
Afzali, N. ,
Abdi-jalebi, M. ,
Vesce, L. ,
Di carlo, A. Nano Today (1878044X) 61
In recent times, organic and perovskite solar cells (OSCs and PSCs) has garnered considerable attention due to the rapid advancement of their impressive photovoltaic performance, achieving power conversion efficiencies exceeding 19 % and 26 %, respectively. Various industrially scalable methods such as blade coating, spray coating, and slot-die coating have been employed to manufacture these promising solar cells, yet the efficiency of devices produced by these methods tends to be lower than those prepared in laboratory scales. To create pinhole-free and high-quality active layer in scalable devices, controlling the crystallization process is required. Therefore, the quality of the active layers plays a pivotal role in constructing efficient and stable solar cells. Among the scalable methods, the slot-die coating method is emerged as particularly attractive for large-scale and cost-effective production of both OSCs and PSCs. Thus, in the current work, we present the strategies to control the morphology of organic and perovskite films prepared by slot-die coating method, such as drying conditions, precursor engineering, solvent engineering, surface modification, and additive engineering, temperature controlling, sequential processing, and ternary blends. Also, the effect of slot-die-coated charge trasportlayers on the OSC and PSC efficiencies and stabilities has been investigatedtransport. Finally, the challenges and potential of commercialization of these promising solar cells, improving their efficiency, quality, and sustainability in the future, are discussed. © 2024 The Authors
Keshavarzi, R. ,
Hajisharifi, F. ,
Afzali, N. ,
Hajisharifi, F. ,
Afzali, N. ,
Keshavarzi, R. 2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 39-65
Photoelectrochemical (PEC) water splitting (WS) holds much promise as a route for the production of hydrogen from solar power. Artificial photosynthesis to store hydrogen produced from solar energy via WS is an attractive topic currently receiving much attention. In a photoelectrochemical cell, water is oxidized to oxygen in the photoanode, and water is reduced to hydrogen in the photocathode. This requires the development of the following: (1) stable electrocatalysts to accelerate processes at each electrode; (2) water-splitting-compatible photosensitizers that efficiently absorb visible light and generate a charge-separated state. In this chapter, we will have an in-depth study of dual electrodes and their different types of arrangement, including tandem and parallel cells. Then, in each case, we discuss PEC/PEC and PEC/PV cells regarding material selection and device optimization. Finally, we provide a brief explanation of PV/EL cells. In the end, we will talk about the perspective of the upcoming challenges, focusing on the critical issues of design and different device structures and their performance limitations from the aspects of photoanode and photocathode. © 2024 Elsevier Ltd. All rights reserved.
Scientific Reports (20452322) 14(1)
Motivated by recent study on synthesized N, N-diphenylaniline (DPA)-based dyes [DOI: https://doi.org/10.1016/j.solener.2022.01.062] for use in dye-sensitized solar cells (DSSCs), we theoretically design several dyes and explore their potential for enhancing the efficiency of DSSCs. Our designed dyes are based on the molecular structure of synthesized DPA-azo-A and DPA-azo-N dyes with a donor-π-bridge-acceptor (D-π-A) framework. In this research, we aim to develop the power conversion efficiency (PCE) of DSSCs by fine-tuning the molecular structure of the synthesized dyes. To this end, we focus on designing dyes by replacing the units of DPA-azo-A and DPA-azo-N with a variety of donor, π-bridge, and acceptor. Hence the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are done to explore their structure, electronic, optical, charge transport, and photovoltaic properties. Among all newly designed and reference dyes, the D3-azo-N and DPA-π3-N dyes which are designed by substituting the donor (DPA) and π-bridge (azo) units of DPA-azo-N with D3 and π3, respectively exhibit the highest PCE of 45.46% (for D3-azo-N) and 43.20% (for DPA-π3-N) and can be favorable dyes for improving the efficiency of DSSCs. Therefore, the dyes that are designed by substituting the donor and π-bridge units of synthesized dyes have more impact on improving the efficiency of DSSCs than those that involve replacing the acceptor units. Consequently, our theoretical findings will provide valuable insights for the experimentalists to employ these novel effective dyes and boost the performance of DSSCs. © The Author(s) 2024.
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 67-107
Recently, metal-organic frameworks (MOFs) as a group of light-harvesting materials with regular two- to three-dimensional buildings, and at the same time, special properties such as mesomicroporosity, high specific surface area, great durability, and tunability had attracted a lot of attention in various fields from catalyst to photocatalyst in different reactions. However, due to the significance of clean energy production by sunlight and the favorable and acceptable performance of these compounds in photoelectrochemical (PEC) processes such as fuel cells, carbon dioxide reduction, PEC water splitting (PECWS), and oxidation of water, these compounds are good candidates for such reactions. This chapter specifically discusses how these materials act as light harvesting in PEC reactions, especially PEC oxidation of water. In this chapter, the following questions will be answered. (1) How light is absorbed in MOF? (2) How electron transitions and excited states are in MOF? (3) What parameters are effective in optimizing MOF as a light harvester? (4) How is the design of PEC cells by MOF? (5) What is the splitting of water by light-absorbing MOF? (6) How many categories are photoelectrodes based on the MOFs divided into? How does each one work? (7) What is the role of light-harvesting MOF in oxygen and hydrogen production reactions? And finally, (8) what are the latest designs for using MOF as a light harvester in PECWS? It will be hoped that by answering these questions in this chapter, a clear path is provided for researchers in this field to better understand the light harvesting in MOFs in PEC reactions. © 2024 Elsevier Ltd. All rights reserved.
Azad, S.S. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. Scientific Reports (20452322) 14(1)
Organometal halide perovskite solar cells have reached a high power conversion efficiency of up to 25.8% but suffered from poor long-term stability against environmental factors such as ultraviolet irradiation and humidity of the environment. Herein, two different multifunctional transparent coatings containing AZO and ZnO porous UV light absorbers were employed on the front of the PSCs. This strategy is designed to improve the long-term stability of PSCs against UV irradiation. Moreover, the provided coatings exhibit two additional roles, including self-cleaning and high wear resistance. In this regard, AZO coating showed higher wear resistance compared to the ZnO coating. The photocatalytic self-cleaning properties of these prepared coatings make them stable against environmental pollutants. Furthermore, appropriate mechanical properties such as high hardness and low coefficient of friction that leads to high resistance against wear are other features of these coatings. The devices with AZO/Glass/FTO/meso-TiO2/Perovskite/spiro/Au and ZnO/Glass/FTO/meso-TiO2/Perovskite/spiro/Au configurations maintained 40% and 30% of their initial performance for 100 h during 11 days (9 h per day) against the UV light with the high intensity of 50 mW cm-2 which is due to higher absorption of AZO compared with ZnO in the ultraviolet region. Since AZO has a higher light transmission in the visible region in comparison to ZnO, perovskite cells with AZO protective layers have higher efficiency than perovskite cells with ZnO layers. It is worth noting that the mentioned features make these coatings usable for cover glass in all types of solar cells. © The Author(s) 2024.
Tavakoli hafshejani, M. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. International Journal of Hydrogen Energy (03603199) 59pp. 82-88
The exceptional optical properties and good temperature stability of inorganic halide perovskites make them appealing materials for photoelectrochemical water splitting. However, their instability towards water molecules is a serious challenge. Our solution to this issue is to use waste carbon-based toner from cartridge printers to protect CsPbBr3-based photoanodes in aqueous electrolytes in an environmentally friendly, cost-effective, and efficient way. Waste carbon toner: graphite (WCTG) protective layer is a novel approach that we present here to recycle these environmentally harmful pollutants. Through adjustment of WCTG ratios, we discovered that the CsPbBr3 photoanodes' photocurrent densities for water oxidation achieved 3.6 and 4.6 mA cm−2 at 1.23 vs reversible hydrogen electrode at pH 7 and pH 12, respectively. After 5 h, the most stable electrodes still maintained their photocurrent density, a critical step towards the circular economy of waste toners and the use of inorganic halide perovskites for solar water splitting. © 2024
Keshavarzi, R. ,
Mousavian, M. ,
Omrani, M. ,
Mirkhani, V. ,
Afzali, N. ,
Mesa, C.A. ,
Mohammadpoor baltork, I. ,
Gimenez, S. Surfaces and Interfaces (24680230) 38
Photoelectrochemical (PEC) water splitting stands out as one of the most promising technologies to store solar energy into chemical bonds and decarbonize industry and transport. In the present study, we develop heterostructured BiVO4/WO3 and TiO2/PANi photoanodes for water oxidation, aiming at maximizing their spectral activity and their light harvesting efficiency, rationalized by a detailed optical modeling of the PEC cell. Furthermore, we implement tandem and parallel dual-photoelectrode configurations to enhance the collection efficiency. Photocurrents of 1.68 and 2.29 mA/cm2 at 1.23 V vs RHE were obtained for tandem and parallel configurations, respectively, demonstrating an enhancement factor 4–6 for Tandem and Parallel cells. © 2023 Elsevier B.V.
Lalpour, N. ,
Mirkhani, V. ,
Keshavarzi, R. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Gao, P. Scientific Reports (20452322) 13(1)
Inorganic hole-transport materials (HTMs) such as copper indium disulfide (CIS) have been applied in perovskite solar cells (PSCs) to improve the poor stability of the conventional Spiro-based PSCs. However, CIS-PSCs' main drawback is their lower efficiency than Spiro-PSCs. In this work, copolymer-templated TiO2 (CT-TiO2) structures have been used as an electron transfer layer (ETL) to improve the photocurrent density and efficiency of CIS-PSCs. Compared to the conventional random porous TiO2 ETLs, copolymer-templated TiO2 ETLs with a lower refractive index improve the transmittance of input light into the cell and therefore enhance the photovoltaic performance. Interestingly, a large number of surface hydroxyl groups on the CT-TiO2 induce a self-healing effect in perovskite. Thus, they provide superior stability in CIS-PSC. The fabricated CIS-PSC presents a conversion efficiency of 11.08% (Jsc = 23.35 mA/cm2, Voc = 0.995, and FF = 0.477) with a device area of 0.09 cm2 under 100 mW/cm2. Moreover, these unsealed CIS-PSCs retained 100% of their performance after aging tests for 90 days under ambient conditions and even increased from 11.08 to 11.27 over time due to self-healing properties. © 2023, The Author(s).
Chemical Papers (03666352) 77(6)pp. 3471-3479
To reach antibacterial decorative faucets with gold color as a controlling parameter, TiCuN thin films containing different amounts of copper (Cu), namely 0.24%, 0.51%, and 1.78%, were prepared on the brass alloy. These different Cu contents were reached by applying various amount of titanium (Ti) and deposition time. The combination of magnetron sputtering and cathode arc deposition physical vapor deposition methods (PVD) in a single chamber was used to fabricate these layers. XRD, XPS, EDS, and FE-SEM analyses were applied to explore physical and chemical properties, and antibacterial tests were used to study the efficiency of modification at different times (1 h, 6 h, and 24 h). The results indicate that all samples benefit from nanoparticle size (20–50 nm), and Cu contact boosts the antibacterial rate. The model with copper content of 1.78% has the best and most stable antibacterial activity against Staphylococcus aureus and Escherichia coli (99.9% after 6 h). © 2022, Institute of Chemistry, Slovak Academy of Sciences.
CHEMICAL PAPERS (03666352) 77(6)pp. 3481-3483
In the original online version, the Fig. 5 and explanations in the text was missing and published. To determine the chemical state of the surface and the surface composition, XPS measurements were performed as well. Figure 5. Shows the full XPS survey spectrum of TiCuN-3. The XPS survey spectrum and the electron dispersed spectroscopy (EDS) confirm the presence of Cu, N, and Ti on the coated sample. The Cu 2p XPS spectrum is shown in Fig. 5b. There are significant peaks for Cu 2p3/2 at 932.5 eV and Cu 2p1/2 at 952.3 eV that confirm the existence of metallic copper. Also, the elemental ratios from XPS were shown a 1.89 w% for the Cu in the TiCuN-3 sample It is noteworthy that these results confirm the electron dispersed spectroscopy data. This result is in good agreement with the literature (Jin et al. 2017). (Figure presented.) (a) XPS survey spectrum for TiCuN-3 and, XPS high-resolution spectra for TiCuN-3 in the fit of (b) Cu 2p region, (c) N 1s region and, (d) Ti 2p region The spelling faucets is misspelled as faucets in figure 1 legend. Figure 5 should be updated as Figure 6. Figure 6 should be updated as Figure 7. The first citation of figure 6 should be updated as figure 6 and figure 7. The second citation of figure 6 should be figure 7. The original article has been corrected. © 2023, Institute of Chemistry, Slovak Academy of Sciences.
Scientific Reports (20452322) 12(1)
This work utilizes a realistic electro-optical coupled simulation to study the (i) impact of mesoporous TiO2 removal; (ii) the embedding of Ag@SiO2 and SiO2@Ag@SiO2 plasmonic nanoparticles; (iii) utilization of solution-processed inorganic p-type copper(I) thiocyanate (CuSCN) layer at the perovskite/carbon interface; and (iv) the increase of the work function of carbon electrodes (via incorporation of suitable additives/binders to the carbon ink) on the performance of carbon-based PSCs. Removal of mesoporous TiO2 increased the power conversion efficiency (PCE) of the device from 14.83 to 16.50% due to the increase in exciton generation rate and charge carriers’ mobility in the vicinity of the perovskite-compact TiO2 interface. Subsequently, variable mass ratios of Ag@SiO2 and SiO2@Ag@SiO2 plasmonic nanoparticles are embedded in the vicinity of the perovskite-compact TiO2 interface. In the optimum cases, the PCE of the devices increased to 19.72% and 18.92%, respectively, due to light trapping, scattering, and strong plasmonic fields produced by the plasmonic nanoparticles. Furthermore, adding the CuSCN layer remarkably increased the PCE of the device with a 0.93% mass ratio of Ag@SiO2 nanoparticles from 19.72 to 26.58% by a significant improvement of Voc and FF, due to the proper interfacial energy band alignment and the reduction of the recombination current density. Similar results were obtained by increasing the carbon work function, and the cell PCE was enhanced up to 26% in the optimal scenario. Our results pave the way to achieve high efficiencies in remarkably stable printable carbon-based PSCs. © 2022, The Author(s).
Jamshidvand, A. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Afzali, N. ,
Nematollahi, J. ,
Amini, M. Journal of Materials Science: Materials in Electronics (09574522) 32(7)pp. 9345-9356
In this paper, a new sensitizer, Ru(4,4′-dicarboxy(phenylethenyl)-2,2′-bipyridine) (4,4′-bis(2-(4-tert-butyloxyphenyl) ethenyl)-2,2′–bipyridine) (NCS)2 with high absorbance coefficient denoting AJ-01, is introduced and its application in dye-sensitized solar cells (DSSCs) is investigated. The synthesized dye was characterized via various analytical methods, such as 1HNMR, 13CNMR, and UV–vis spectroscopic methods, and finally, it was utilized as a visible-light sensitizer in DSSCs. The AJ-01 photovoltaic performances were compared with that of N-719 as a commonly used sensitizer and were evaluated under similar conditions. UV–Vis absorption spectra for the AJ-01 sensitizer were also showed that the molar extinction coefficients much higher than the N-719 sensitizer at the peak wavelengths of the new sensitizer. Furthermore, Ab initio calculations were used to clarify the electronic properties and the role of the anchoring ligands at the rate of electron transfer to TiO2. The photovoltaic parameters of the AJ-01 sensitizer cell show an open-circuit voltage (Voc) of 0.764 V, short-circuit current density (Jsc) of 20.11 mA cm−2 and fill factor (F.F.) of 0.55, and a power conversion efficiency of 8.4%. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Sadegh, F. ,
Akin, S. ,
Moghadam, M. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Ruiz-preciado, M.A. ,
Akman, E. ,
Zhang, H. ,
Amini, M. ,
Tangestaninejad, S. Advanced Functional Materials (1616301X) 31(33)
Despite the outstanding role of mesoscopic structures on the efficiency and stability of perovskite solar cells (PSCs) in the regular (n–i–p) architecture, mesoscopic PSCs in inverted (p–i–n) architecture have rarely been reported. Herein, an efficient and stable mesoscopic NiOx (mp-NiOx) scaffold formed via a simple and low-cost triblock copolymer template-assisted strategy is employed, and this mp-NiOx film is utilized as a hole transport layer (HTL) in PSCs, for the first time. Promisingly, this approach allows the fabrication of homogenous, crack-free, and robust 150 nm thick mp-NiOx HTLs through a facile chemical approach. Such a high-quality templated mp-NiOx structure promotes the growth of the perovskite film yielding better surface coverage and enlarged grains. These desired structural and morphological features effectively translate into improved charge extraction, accelerated charge transportation, and suppressed trap-assisted recombination. Ultimately, a considerable efficiency of 20.2% is achieved with negligible hysteresis which is among the highest efficiencies for mp-NiOx based inverted PSCs so far. Moreover, mesoscopic devices indicate higher long-term stability under ambient conditions compared to planar devices. Overall, these results may set new benchmarks in terms of performance for mesoscopic inverted PSCs employing templated mp-NiOx films as highly efficient, stable, and easy fabricated HTLs. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH.
Golabi, P. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Abrams, N.M. Journal of Power Sources (03787753) 512
Improving light-harvesting conversion efficiency (η) is a major step towards commercializing perovskite solar cells (PSCs). Inverse opals prepared from TiO2 show enhanced light absorption, and improved efficiency, due to increased light scattering. Besides improving efficiency, the cells are colorful and aesthetically pleasing for use in practical applications. In this study, three-dimensional (3D) highly-porous inverse opals were fabricated for use in PSCs. The light-harvesting efficiency (LHE%) and the photovoltaic performance of these colorful ordered structures were studied for the first time. Moreover, two different architectures are presented by integrating a mesoporous TiO2 (mp-TiO2) layer with an optically active two-dimensional TiO2 film. Herein, we report the highest known power conversion efficiency for bilayer TiO2/PSCs compared to standard mesoporous TiO2 films. The data indicate improved incident photon to current conversion efficiency values due to enhanced quantum efficiency in the red range of the electromagnetic spectrum. Other approaches relating to the characteristics of optical properties and photovoltaic performances of different geometries of PSCs are discussed. © 2021 Elsevier B.V.
Afzali, N. ,
Keshavarzi, R. ,
Tangestaninejad, S. ,
Gimenez, S. ,
Mirkhani, V. ,
Moghadam, M. ,
Mohammadpoor baltork, I. Applied Materials Today (23529415) 24
Metal-Organic Frameworks (MOFs) are a group of compounds with high porosity and diverse capabilities in photoelectrochemistry. The use of these compounds as photocatalysts and photoelectrodes is still a strong challenge due to bulk and surface recombination issues. To solve this problem, we applied a dual strategy to simultaneously enhance charge separation and catalytic activity in MIL-125-NH2 and UIO-66-NH2 MOF photocatalysts. Mesoporous TiO2 was used as electron-selective contact on the MOF surface (MOF/TiO2) to minimize bulk recombination. On the other hand, to increase the MOF catalytic activity for water oxidation, a well-matched Co3(PO4)2 (CoPi) co-catalyst (CoPi/MOF/TiO2) was used. The obtained results showed that CoPi and TiO2 were introduced in the MOF structure. The (CoPi/MOF/TiO2) photoelectrodes showed a photocurrent density 26 times higher compared to the reference MOF at 1.23 V vs. RHE for PEC water oxidation of artificial seawater, validating the developed strategy for further photocatalytic and photoelectrochemical applications. © 2021
Afzali, N. ,
Tangestaninejad, S. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Nematollahi, J. ,
Moghadam, M. ,
Mohammadpoor baltork, I. ,
Reimer, M. ,
Olthof, S. ,
Klein, A. ACS Sustainable Chemistry and Engineering (21680485) 8(50)pp. 18366-18376
The Ti-based metal-organic framework (MOF) MIL-125-NH2 is one of the promising materials for solar water splitting because it contains a sensitizer and a catalytic center in a single structure. MIL-125-NH2 as many other MOFs has a microporous structure with pore diameters less than 2 nm. Compared with common MOFs, hierarchical mesoporous materials exhibit very large specific surface areas that facilitate diffusion of active species, accelerate subsequent surface reactions, and increase the bubble release rate by providing larger free spaces. Thus, the development of a facile method to create hierarchical porous MOFs with larger pore sizes remains a chemical challenge. Furthermore, MOF-type semiconducting materials usually have low activities in oxygen evolution reaction, and the presence of a suitable cocatalyst is needed to reduce the large O2 overpotential. This study attempted to generate a hierarchical MIL-125-NH2 MOF material with embedded RuO2 nanoparticles as a highly efficient cocatalyst in a simple one-step process for use in efficient solar water oxidation. Different amounts of RuCl3H2O precursor salt were used simultaneously for creating hierarchical porosity in MIL-125-NH2 and for producing the assumed RuO2 cocatalyst. For comparison, a hydrochloric acid treatment was applied to generate hierarchical porosity in the MOF in the absence of ruthenium. The samples were characterized using high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller adsorption, powder X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. HRTEM gave evidence that in the ruthenium oxide-containing MIL-125-NH2 samples, tetragonal RuO2 nanoparticles are present. The materials were applied as photoelectrodes, and photoelectrochemical (PEC) water oxidation performance under visible light illumination was studied. The PEC water oxidation performance of the MIL-125-NH2 layer could be strikingly improved with a photocurrent density of about 10 times more than that of the pure MOF at 1.23 V versus reversible hydrogen electrode in artificial seawater, as a result of the hierarchical MOF structure and the presence of RuO2 as a cocatalyst. Furthermore, density functional theory calculations were performed to shed light on the electronic properties and the role of the RuO2 in the assumed hole transport. ©
Solar RRL (2367198X) 4(12)
Low-cost carbon-based perovskite solar cells (C-PSCs) without a hole transport layer (HTL) and metal contact are highly promising for marketing. However, lower efficiency than conventional PSCs and instability during the penetration of moisture through the porous carbon electrode as well as the incoming of ultraviolet (UV) light from the glass side of the device remain challenges. Herein, a multifunctional triple-layer system containing TiO2/SiO2/CeO2 porous nanomaterials is numerically simulated and experimentally used on the glass side of HTL-free C-PSCs. This strategy is designed to increase cell efficiency by enhancing the antireflective feature and long-term stability via the UV light blocking and superhydrophobic properties introduced to the surface. Furthermore, this system is durable against environmental pollutants due to the photocatalytic self-cleaning effect of TiO2. A superhydrophobic carbon back contact is also used to sandwich the perovskite active layer between two superhydrophobic surfaces and further the humidity resilience of the device. The device with polydimethylsiloxane (PDMS)–TiO2/SiO2/CeO2/glass/meso-TiO2/MAPbI3/superhydrophobic-carbon configuration shows an efficiency of 16.60% among the HTL-free C-PSCs and superior long-term stability (maintaining 98.5% of the initial efficiency without encapsulation) against UV light and relative humidity of 90% at 50 °C. © 2020 Wiley-VCH GmbH
Sheibani, E. ,
Amini, M. ,
Heydari, M. ,
Ahangar, H. ,
Keshavarzi, R. ,
Zhang, J. ,
Mirkhani, V. Solar Energy (0038092X) 194pp. 279-285
N-annulated perylene based materials show outstanding and tunable optical and physical properties, making them suitable to be charge transport materials for optoelectronic applications. However, this type of materials has so far not been well studied in solar cells. Here, we develop a new hole transport material (HTM), namely S5, based on perylene building block terms, for organic-inorganic hybrid perovskite solar cells (PSCs). We have systematically studied the influences of the film thickness of S5 on their photovoltaic performance, and a low concentration of S5 with a thinner HTM film is favorable for obtaining higher solar cell efficiency. S5 shows excellent energy alignment with perovskite as well as high-quality thin film formation, and the PSCs based on S5 as HTMs show remarkable power conversion efficiency (PCE) of 14.90% with a much higher short-circuit photocurrent than that for conventional HTM spiro-OMeTAD (PCE = 13.01%). We conclude that the superior photocurrent for S5 is mainly attributed to the enhanced interfacial hole transfer kinetics as well as the high hole conductivity. In addition, we have investigated the stability of N-annulated perylene derivative as HTMs in PSCs devices, showing that the unencapsulated devices based on S5 demonstrate outstanding stability by remaining 85% of initial PCEs in ambient condition with a relative humidity of ~30–45% for 500 h, while for devices with spiro-OMeTAD the cell efficiency degrade to 57% of initial performance at the same conditions. © 2019 International Solar Energy Society
Amini, M. ,
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Sadegh, F. Journal of Materials Chemistry A (20507496) 6(6)pp. 2632-2642
In this study, we have tried to demonstrate the implications of employing nonsimilar mesoporous TiO2 templated films as interfacial blocking layers for improving the input light transmittance and photovoltaic performance of dye sensitized and perovskite solar cells. In fact, the interfacial layers were synthesized using four types of copolymers including PSA, Brij58, P123 and F127 and their impact on the performance of dye sensitized and perovskite solar cells was examined and compared with that of traditional dense blocking layers. For the first time, we used block copolymers as structure-directing agents in interfacial templated blocking films aiming at increasing the input light transmittance and efficiency of dye sensitized and perovskite solar cells. Moreover, two types of FTO substrates, 15 Ω sq-1 with high light transmission and low conductivity, and 7 Ω sq-1 with low transmittance and high conductivity, were used in order to replace FTO glasses with higher conductivity instead of 15 Ω sq-1 glasses commonly used. Our results showed that, through replacing the blocking layer templated using the P123 copolymer with dense film, the short circuit density significantly improved from 15.89 to 21.23 mA cm-2 for the dye sensitized solar cell and from 18.72 to 24.09 mA cm-2 for the perovskite solar cell due to the striking increase in light transmittance. Also, introduction of the P123 templated interfacial layer presents conversion efficiency enhancement by 33% and 16% in the dye sensitized solar cell and perovskite solar cell, respectively. © 2018 The Royal Society of Chemistry.
Jamshidvand, A. ,
Sahihi, M. ,
Mirkhani, V. ,
Moghadam, M. ,
Mohammadpoor baltork, I. ,
Tangestaninejad, S. ,
Amiri rudbari, H. ,
Kargar, H. ,
Keshavarzi, R. ,
Gharaghani, S. Journal of Molecular Liquids (18733166) 253pp. 61-71
In this work, five new Schiff base ligands were synthesized and characterized by 1H NMR, 13C NMR, FT-IR, UV–Vis and elemental analysis (CHN). L1, L2 and L3, were derived from condensation of 2-Hydroxy-5-bromobenzaldehyde with 4-aminobenzoic acid, 3-aminobenzoic acid and 3-amino-4-methylbenzoic acid with 1:1 M ratio, respectively. While, L4 and L5 were prepared from condensation of 4-aminobenzoate with 3-ethoxy-2-hydroxybenzaldehyde and 3-methoxy-2-hydroxybenzaldehyd with 1:1 M ratio, respectively. Furthermore, the crystal structure of L4 and L5 were determined by single crystal X-ray analysis. The interaction of Schiff base ligands with fish sperm DNA (FS-DNA) was investigated under physiological conditions using fluorescence quenching, UV–Vis spectroscopy, molecular docking and molecular dynamics (MD) simulation methods. The estimated binding constants (kb) for the DNA-Ligands complexes were 8.9 × 104 M−1, 6.8 × 104 M−1, 1.2 × 105 M−1, 2.3 × 105 M−1, 1.7 × 105 M−1 for L1, L2, L3, L4 and L5, respectively. Based on similarity of the ligands structures and their Kb values, their affinity for binding to FS-DNA follow as: L3 > L1 > L2 and L4 > L5. The results revealed that ligands with stronger electron donating substituents, have higher DNA-binding ability than the others. Also, molecular docking results show that all of the synthesized ligands are minor groove binders and H-bond interactions have dominant role in the stability of ligand-DNA complexes. © 2018 Elsevier B.V.
Keshavarzi, R. ,
Jamshidvand, A. ,
Mirkhani, V. ,
Tangestaninejad, S. ,
Moghadam, M. ,
Mohammadpoor baltork, I. Materials Science in Semiconductor Processing (13698001) 73pp. 99-105
Crack free titania thick templated films were prepared by evaporation-induced self-assembly (EISA) process and spin coating method with different numbers of calcination steps; then, their application in dye sensitized solar cells (DSSC) was investigated. Wormlike meso-layers prepared at different spin speeds were characterized by TEM analysis. The correlation between spin speed and thickness and porosity of the films were investigated using ellipsometry method. The crystallinity and surface area of the films obtained at a repeated thermal treatment method and different temperatures were investigated by XRD and BET techniques. UV–vis spectroscopy and cross-sectional SEM images were also used to characterize the films. Finally, the mesoporous thick films (5.7 µm) were used in DSSC devices and their photovoltaic performances were examined. The optimum mesoporous film exhibited an open-circuit voltage (VOC) of 0.729 V, short-circuit current density (JSC) of 14.93 mA cm−2, fill factor of 0.68 and a power conversion efficiency of 7.35%. © 2017 Elsevier Ltd
Nasirian, A. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Keshavarzi, R. Applied Solar Energy (English translation of Geliotekhnika) (0003701X) 52(1)pp. 32-39
In this work, nanocrystalline P25 TiO2 films with different thicknesses were deposited on FTO coated glass substrates by an electrophoretic deposition technique (EPD) and applied as the work electrode for dye-sensitized solar cells (DSSC) using cis-bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato)(4,4'di-nonyl-2'-bipyridyl) ruthenium(II) (Z907, Dyesol) as sensitizing dye.The results showed that the increasing the thickness of TiO2 films lead to increase the adsorption of the dye on the TiO2 layers which in turns improved the short-circuit photocurrent (Jsc) and open-circuit voltage (Voc), respectively. Furthermore, it was found that the effects of the surface states on the recombination of the photo-injected electrons (electron–hole pairs) in the TiO2 films strongly depend on theTiO2 electrode annealing temperature. Finally, a DSSC with a 32.82 μm thickness for TiO2 film annealed at 600°C produced the highest conversion efficiency with an incident solar energy of 100 mW/cm2 (η = 8.23%, Jsc = 15.98, Voc = 0.73, FF = 0.7). © 2016, Allerton Press, Inc.
Journal of Materials Chemistry A (20507496) 3(5)pp. 2294-2304
Ordered and disordered mesoporous titania thick films up to about 7 μm thickness were successfully synthesized by an evaporation-induced self-assembly (EISA) process using dip and spin coating methods. To obtain crack-free thick films with high crystallinity and roughness factor we used a stabilization step after each coating and a calcination step after every five layers. Transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), BET analysis, ellipsometric analysis and UV-visible absorption spectroscopy (UV-vis) were used to characterize the microstructural features of the films. These mesoporous TiO2 thick films were tested in dye-sensitized solar cells (DSSCs). The photovoltaic performances of cells made from meso-films prepared by dip and spin coating methods were compared and a maximum efficiency of 8.33% was achieved. This is the highest efficiency so far reported for DSSCs made from mesoporous titania templated films. The mesostructured films were compared with nanocrystalline TiO2 films (NC-TiO2) that are commonly used in DSSCs and showed superior performance. © The Royal Society of Chemistry 2015.
Rismanchian, M. ,
Barakat, S. ,
Khoshzat, N. ,
Keshavarzi, R. ,
Shakerian, M. International Journal of Environmental Health Engineering (22779183) 4(1)
Aims: This study was aimed to determine the TiO2/zeolite photocatalytic activity for removing red Safranin dye form aqueous phase. Materials and Methods: In this study, TiO2 nanoparticles were produced using sol-gel method and 2.5 ml sol-gel was coated on 1.2222 g of zeolite. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to specify the structure and morphology of TiO2 nanoparticles. The effect of TiO2 coating on zeolite, ultraviolet (UV) radiation intensity, initial concentration of dye and the type of photocatalyst substrate (fixed and moving) on photocatalytic process was investigated. Results: According to XRD results, the TiO2 nanoparticles had two phases including anatase (80.5%) and rutile (19.5%). The uniformity of nanoparticles was obvious in the SEM images. The removal efficiency of TiO2 coated on zeolite was higher than TiO2 photocatalysis with increasing UV radiation intensity from 2.4 w/m2 to 3.9 w/m2, the photocatalytic efficiency was also enhanced. The removal efficiency decreased from 91.61% to 77.91% by increasing the red Safranin dye concentration from 10 mg/L to 50 mg/L. The moving bed of TiO2/zeolite photocatalyst had a higher efficiency than the fixed bed. Conclusion: In over all, the TiO2/zeolite photocatalyst was much more effective than TiO2 photocatalyst for Safranin dye removal from the aqueous phase. With increasing UV radiation intensity and decreasing dye concentration photocatalytic efficiency, was improved. TiO2/zeolite photocatalyst with fixed bed is recommended to be used in water treatment. The most important problem of using moving-bed TiO2/zeolite photocatalyst in the water treatment is opacity. Copyright: © 2015 Masoud R. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Langmuir (15205827) 31(42)pp. 11659-11670
This study is an attempt to give an account of the preparation of mesoporous TiO2 thick templated films of nonsimilar pore architecture and their use in dye-sensitized solar cells (DSSCs). Highly crystallized mesoporous titania thick templated films with four different morphologies including hexagonal, wormlike, cubic, and gridlike mesostructure, have been successfully synthesized through an evaporation-induced self-assembly (EISA) route followed by layer-by-layer deposition. Stabilization, followed by each coating, and calcinations, carried out after every five layers, were used to produce crack-free thick films. These mesoporous templated titanium dioxide samples were characterized by TEM, XRD, SEM, BET, and UV-vis measurements and used as a photoelectrode material in DSSCs. The mesostructured films with a thickness of about 7 μm demonstrated better performance in comparison to nanocrystalline TiO2 films (NC-TiO2) at a film thickness of 13 μm as the most typical films utilized in DSSCs. The findings reveal that a surfactant/Ti ratio change undergone for developing cubic mesostructures can enhance the crystallinity and roughness factor and therefore increase the energy conversion efficiency of DSSC. The cell performances derived from these mesofilms were enhanced compared to the efficiencies reported thus far. The best photovoltaic performance of 8.73% came from DSSC using the cubic mesoporous TiO2 photoelectrode with the following properties: open circuit voltage of 743 mV, short circuit photocurrent density of 16.35 mA/cm2, and fill factor of 0.72. © 2015 American Chemical Society.
International Journal of Environmental Health Engineering (22779183) 4(21)
Aims: The purpose of this study was to remove azonium compound using the photocatalytic property of nickel (Ni)-doped titanium dioxide (TiO2) nanoparticles coated on Iranian natural zeolite. Materials and Methods: Nickel-doped TiO2 nanoparticles with the molar ratios of 0, 0.17, 2, 9% Ni/TiO2 were prepared via the sol-gel process and coated on Iranian natural zeolite clinoptilolite (CLI). Afterward, X-ray diffraction, scanning electron microscopy and inductively coupled plasma studies were conducted to describe Ni and titanium. Photocatalytic removal of azo dye in concentrations of 25 and 50 mg/L was performed by fixing the composite under ultraviolet irradiation. Results: TiO2 nanoparticles in both the anatase and rutile phases were obtained via the sol-gel method with the ratios of 86.33%, (34.44 nm particle size) and 13.67% (18 nm particle size) and were then coated on Iranian natural CLI zeolite. The results indicated that the photocatalytic removal efficiency of the 9% Ni/TiO2-CLI samples, in which the azo dye concentrations were 25 and 50 mg/L, was 93% and 79% at 160 min. In addition, the composition of the 9% Ni/TiO2-CLI possessed the greatest removal rate difference of azo dye at the concentrations of 25 and 50 mg/L. Conclusion: Application of Iranian CLI as a substrate is the most cost-effective way to increase the photocatalytic activity. Furthermore, adding Ni to TiO2 can increase the photocatalyst removal efficiency of azonium compound. Copyright: © 2015 Rismanchian M.
International Journal of Environmental Health Engineering (22779183) 3(2)pp. 76-81
Aims: The aim of this study is to determine the impact of relative humidity (RH) and contaminant concentration on photocatalytic conversion of gaseous toluene by using TiO2 coated on nickel foam. Materials and Methods: TiO2 nanoparticles were prepared by the sol-gel process and coated on nickel foam. Structural and morphological characteristics of nanoparticles were determined using Scanning electron microscope, X-ray diffraction analysis. Photocatalytic conversion of gaseous toluene at the different levels of RH and toluene concentration was measured under ultraviolet-A radiation by gas chromatograph with Flame Ionization Detector. Results: After being fixed the contaminant concentration, 30% level of RH had the most impact on the photocatalytic efficiency, 10, 0,5 0 and 80% levels of humidity had, in turn, the most impact. Results also showed that TiO2 nanoparticles coated on nickel foam at the concentration of 20 ppm had the most efficiency of photocatalytic conversion. After that, the most efficiency was recorded at the 10 and 50 ppm concentrations, respectively. Conclusion: Based on the results, the photocatalytic conversion of gaseous phase toluene by TiO2 coated nickel foam is increased with the increase of RH to a certain level; beyond that the conversion efficiency is decreased gradually due to the saturation of photocatalyst surface and decrease in nanoparticle activity. Furthermore, photocatalytic conversion of gaseous toluene is decreased with the increase of toluene concentration. © 2014 Rismanchian M. This is an open‑access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Keshavarzi, R. ,
Mirkhani, V. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. ,
Fallah, H. ,
Dastjerdi, M.J.V. ,
Modayemzadeh, H.R. Materials Research Bulletin (00255408) 46(4)pp. 615-620
In this work, the preparation of In2O3-ZnO thin films by electron beam evaporation technique on glass substrates is reported. Optical and electrical properties of these films were investigated. The effect of dopant amount and annealing temperature on the optical and electrical properties of In2O3-ZnO thin films was also studied. Different amount of ZnO was used as dopant and the films were annealed at different temperature. The results showed that the most crystalline, transparent and uniform films with lowest resistivity were obtained using 25 wt% of ZnO annealed at 500 °C. © 2010 Elsevier Ltd © 2011 Elsevier Ltd. All rights reserved.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (03029743) 5139pp. 675-682
Information extraction (IE) has been emerged as a novel discipline in computer science. In IE, intelligent algorithms are employed to extract the required data, and structure them so that they are appropriate for query. In most IE systems, a web-page structure, e.g. HTML tags are used to recognize the looked-for information. In this article, an algorithm is developed to recognize the main region of web-pages containing the looked-for information, by means of an ontology, a web-page structure and goodness-of-fit χ 2 test. After recognizing the main region, the existing records of the region are recognized, and then each record is put in a text file. © 2008 Springer-Verlag Berlin Heidelberg.
