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2. The role of fluorine-functionalized organic spacers for defect passivation and low-dimensional phase formation in 3D MAPI perovskite solar cellsAli Semerci, Javier Urieta-Mora, Sander Driessen, Ali Buyruk, Rik Hooijer, Agustín Molina-Ontoria, Bülent Alkan, Seckin Akin, Mattia Fanetti, Saim Emin, 2025, izvirni znanstveni članek Opis: Widespread application of organic-inorganic halide perovskites (OIHP) still faces a major obstacle in mitigating moisture-induced degradation. Integrating organic spacers, as defect passivation facilitators along with low-dimensional phase (LDP) formation is an effective approach to enhance the efficiency and robustness of 3D methyl ammonium lead iodide (MAPI) in photovoltaics (PV). Here, the formamidinium cation (FA+) employing 3,5-difluorobenzene-1-carboximidamidium iodide (2F), 4-(trifluoromethyl)benzene-1-carboximidamidium iodide (3F),
and 2,3,4,5,6-pentafluorobenzene-1-carboximidamidium iodide (5F) organic spacers as passivation layer in 3D/LDP OIHP solar cells is utilized. Fluorine atom position and quantity in organic spacers change the optoelectronic characteristics of the perovskites, enhancing hydrophobicity, facilitating LDP formation, and augmenting dipole moments, thereby facilitating charge separation processes. PV performance analysis reveals that 3F-treated 3D/LDP devices achieve the highest efficiency of 19.22%. Experimental results and density functional theory (DFT) studies attribute the higher performance of 3F-modified devices to effective LDP formation, enhanced passivation of defect states at perovskite surfaces and grain boundaries, the highest dipole moment and lowest band gap among the evaluated spacers. The stability tests show that, after 1000 h, 3F- and 5F-modified 3D/LDP OIHP devices retain over 85% of their initial efficiency. This research opens novel avenues for designing appropriate organic spacers to attenuate defects in 3D/LDP PV devices.
Ključne besede: fluorine-functionalized molecules, MAPI perovskite solar cells, deffect passivation
Objavljeno v RUNG: 20.02.2025; Ogledov: 710; Prenosov: 4
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3. Colloidal metal nanoparticles as a source for the growth of thin filmsSaim Emin, 2022, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: Synthesis of colloidal nanoparticles (NPs) which offer good colloidal stability is quite important for different applications like spin-coating, dip-coating etc. Having metallic nanoparticles in the form of stable suspension allow the generation of thin films with desired thicknesses. We will present the production of different classes of materials starting from colloidal metal NPs. An example will be given on the preparation of Fe2O3 and WO3 thin films which are used in photoelectrochemical oxidation of water (e.g. water splitting). Another transformation which involves metallic NPs include the preparation of MoSe2 and WSe2 thin films which is achieved in a tube furnace at elevated temperatures. Very recently, the use of metallic NPs were also extended for the preparation of transition metal carbides. We managed to produce W2C and WC phases starting from metallic W NPs. The details of this phase conversion will be discussed. The presentation will provide details on how transition metallic NPs can be used to prepare metal oxide, metal selenide and metal carbides.
Ključne besede: colloidal metal nanoparticles, thin films, water splitting
Objavljeno v RUNG: 16.01.2025; Ogledov: 977; Prenosov: 0
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4. Iron phosphide electrocatalyst for renewable production of value-added productsTakwa Chouki, Manel Machreki, Iwona A. Rutkowska, Beata Rytelewska, Pawel Jozef Kulesza, Georgi Tyuliev, Moussab Harb, Luis Miguel Azofra, Saim Emin, 2022, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: The electrochemical reduction reaction of the nitrate ion (NO3) to valuable ammonia (NH3) is a promising green approach. Herein, we report for the the electrocatalytic reduction of NO3 using different phases of iron phosphide. Particularly, FeP and Fe2P phases were successfully demonstrated as efficient catalysts for NH3 generation. The Fe2P catalyst exhibits the highest Faradaic efficiency (96%) for NH3 generation with a yield (0.25 mmol h−1 cm-−2) at −0.55 V vs. reversible hydrogen electrode (RHE). The recycling tests confirmed that Fe2P and FeP catalysts exhibit excellent stability during the NO3 reduction at −0.37 V vs. RHE. These results indicate that the Fe2P phase exhibits excellent performance to be deployed as an efficient noble metal-free catalyst for NH3 generation. In addition to NO3 reduction the iron phosphide phases were used in electrocatalytic H2 generation using water electrolysis. The electrocatalytic activities of heat-treated Fe2P−450°C, Fe3P−500°C, and Fe2P/FeP−500°C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H2SO4. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with a mixed Fe2P/FeP−500°C catalyst.
Ključne besede: electrochemical reduction, nitrate reduction, iron phosphide catalyst, NH3 generation
Objavljeno v RUNG: 10.01.2025; Ogledov: 668; Prenosov: 2
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5. In situ treatment of organic pollutants in water using photoelectrocatalysisSaim Emin, Takwa Chouki, Manel Machreki, 2022, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: The photoelectrochemical (PEC) approach has emerged as a promising advanced oxidation process to remove organic pollutants in water environment. Here, we report a novel method for the preparation of hematite (α-Fe2O3) thin films by using a combination of spin-coating and heat-treatment approaches. Firstly, a solution containing iron precursor was spin-coated on fluorine doped tin oxide substrates and later heat-treated at 750º C to generates a porous film.1 The α-Fe2O3 thin films were studied as a catalyst in PEC water oxidation and textile dye degradation system We applied the α-Fe2O3 thin films in PEC degradation of a textile Basic Blue 41 (B41) dye. Efficient PEC degradation of B41 dye is demonstrated in the presence of reactive chlorine species (RCS) under LED illumination (λex 400 nm, 20 W) and 1.5 V vs. reversible hydrogen electrode applied potential. In addition to Fe2O3, we also grew TiO2 nanotubes on titanium plate using the so-called anodization approach. We applied the obtained TiO2 thin films in PEC degradation of B41 dye. In addition to the B41 textile dye, we used also used the TiO2 nanotubes for degradation of anti-inflammatory drugs. Various operation parameters, including anodic potential, pH, electrolytes and concentration of dye, were investigated to determine the optimal experimental conditions. The degradation of B41 was remarkably enhanced by in situ generated RCS. Recycling test revealed that α-Fe2O3 photoanode shows good activity and excellent stability during B41 degradation. High-performance liquid chromatography analysis coupled with UV-VIS system and gas-chromatography/liquid chromatography coupled to mass spectrometry detector confirmed the degradation of B41 dye and the evolution of by-product. Phytotoxicity test using Lepidium sativum L showed that treated waters are safe to be discharged in the environment.
Ključne besede: photoelectrocatalysis, Fe2O3 thin films, basic blue dye 41
Objavljeno v RUNG: 10.01.2025; Ogledov: 691; Prenosov: 2
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6. Biotechnological recycling and recovery of metals from secondary raw materials through biogenic synthesis of nanoparticlesSvetlin Toshev, Alexandre Loukanov, Saim Emin, Seilichiro Nakabayashi, 2021, izvirni znanstveni članek Opis: The waste electrical and electronic equipment (WEEE) is an important secondary source for renewable extraction of valuable metals and raw materials.
The mineral biotechnologies are promising alternative to the current industrial chemical technologies for waste treatment, which are often accompanied with negative environmental impact. Here we report a systematic biotechnological strategy for recycling, recovering and extraction of metals from WEEE as biogenic formed nanoparticles. The process is based on two general steps – bioleaching (through autotrophic/heterotrophic bacteria), and extraction from the effluent as biosynthesised nanoscale materials. The obtained analytical data revealed that copper was bioleached in the form of nanoparticles, the efficiency being more than 90 %, which was the highest achieved value in comparison with the other metals. The recovered content of gold was less than 50 %, but the efforts for improvement of microbial leaching efficiency of Au are still in progress. The reported eco–friendly biotechnological approach enables proper implementation of new resource recovery–oriented recycling strategies with reduced risk of negative impact on nature.
Ključne besede: biotechnological recycling, secondary raw materials, nanoparticles
Objavljeno v RUNG: 10.01.2025; Ogledov: 581; Prenosov: 4
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7. Photoelectrochemical conversion of biomass alcohols using in-situ Sn-doped ▫$\alpha-Fe_2O_3$▫ thin filmsManel Machreki, Artem Badasyan, Dušan Žigon, Georgi Tyuliev, Saim Emin, 2025, izvirni znanstveni članek Opis: Transformation of biomass into value-added chemicals and fuels is considered an upcycling process that is beneficial to resource utilization. In this study, we used a photoelectrochemical (PEC) approach for selective oxidation of propane-1,2,3-triol to dihydroxyacetone (DHA) with high efficiency and selectivity (99%) using Sn-doped -Fe2O3 (Sn:-Fe2O3) thin films with intrinsic oxygen vacancies (OVs). DHA is an essential compound utilized in the cosmetic industry. In a similar manner, we conducted the first study of the PEC oxidation of 4-hydroxy-3-methoxybenzyl alcohol under visible light. A kinetic model has been formulated and solved to find the time-dependent generation of the products. Electrochemical impedance analyses and PEC experiments demonstrated a correlation between the concentration of molecules and the catalytic performance of Sn:-Fe2O3. Studies using scavengers indicate that the photogenerated holes (h+), singlet oxygen (1O2), hydroxyl radicals (•OH), and superoxide radicals (•O2–) play key roles in achieving high PEC activity. This work provided a new perspective on designing efficient PEC systems for biomass conversion into energy and value-added chemicals.
Ključne besede: Sn-doped alpha-Fe2O3, oxygen vacancies, photoelectrochemical oxidation, propane-1, 2, 3-triol, 4-hydroxy-3-methoxybenzyl alcohol
Objavljeno v RUNG: 08.01.2025; Ogledov: 710; Prenosov: 6
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