The enhancement of the photovoltaic performance upon the aging process at particular environment is often observed in perovskite solar cells (PSCs), particularly for the devices with 2,2′,7,7′‐tetrakis(N,N‐di(4‐methoxyphenyl)amino)−9,9′‐spirobifluorene (spiro‐OMeTAD) as hole transporting material (HTM). In this work, for the first time the effect of aging the typical n‐i‐p PSCs employing nickel phthalocyanine (coded as Bis‐PF‐Ni) solely as dopant‐free HTM is investigated and as an additive in spiro‐OMeTAD solution. This study reveals that the prolong aging of these devices at dry air condition (RH = 2%, 25 °C) is beneficial for the improvement of their performances. Various bulk and surface characterization techniques are utilized to understand the factors behind the spontaneous efficiency enhancement of the devices after storage. As a result, the changes in properties of the Bis‐PF‐Ni layer are observed and at perovskite/Bis‐PF‐Ni interface, which ultimately improves the charge transport and reduces non‐radiative recombination. In addition, the devices with Bis‐PF‐Ni HTM reveal enhanced long‐term ambient and thermal stability compared to the PSCs based on doped spiro‐OMeTAD.
Depending on the feedstock type and the pyrolysis conditions, biochars exhibit different physical, chemical, and structural properties, which highly influence their performance in various applications. This study presents a comprehensive characterization of biochar materials derived from the waste wood of pine (Pinus sylvestris L.) and beech (Fagus sylvatica) after low-temperature pyrolysis at 270 °C, followed by chemical activation using zinc chloride. The resulting materials were thoroughly analyzed in terms of their chemical composition (FTIR), thermal behavior (TGA/DTG), structural morphology (SEM and XRD), elemental analysis, and particle size distribution. The successful modification of raw biomass into carbon-rich structures of increased aromaticity and thermal stability was confirmed. Particle size analysis revealed that the activated carbon of Fagus sylvatica (FSAC) exhibited a monomodal distribution, indicating high homogeneity, whereas Pinus sylvestris-activated carbon showed a distinct bimodal distribution. This heterogeneity was supported by elemental analysis, revealing a higher inorganic content in pine-activated carbon, likely contributing to its dimensional instability during activation. These findings suggest that the uniform morphology of beech-activated carbon may be advantageous in filtration and adsorption applications, while pine-activated carbon’s heterogeneous structure could be beneficial for multifunctional systems requiring variable pore architectures. Overall, this study underscored the potential of chemically activated biochar from lignocellulosic residues for customized applications in environmental and material science domains.
1 January 2025 in Applied Organometallic Chemistry
Utilizing natural bioactive compounds to enhance the service life of wood materials is a promising approach from both human health and environmental preservation perspectives. In recent years, significant efforts have been made to explore, develop, and refine new organic compounds for use in bio-composite production and wood preservation. In this study, pentaerythritol ester rosin (PEK) was synthesized and combined with epoxidized soybean oil (ESO) and Pinus sylvestris L. wood samples were impregnated with this solution prepared at different concentrations. Since PEK is prone to leaching from wood, it was blended with epoxidized vegetable oils to create a synergistic effect, ensuring stronger chemical bonding with the hydroxyl groups in wood. Various physical, chemical tests and analyses were conducted on the impregnated wood samples to evaluate their performance. The results showed that 20.0% PEK + ESO impregnation mixture was the most effective mixture for dimensional stability. This bio-based preservative system aims to extend the service life of woods while reducing reliance on petroleum-derived chemicals and heavy metals, thereby lowering the environmental footprint of wood protection.