Understanding the polaron behavior in Cs2CuSbCl6 halide double perovskite.

Lead-free halide double perovskites A2MM'X6 (A = Rb+, Cs+, etc.; M = Ag+, K+, Li+; M' = Sb3+, In3+ or Bi3+ and X = I-, Br- or Cl-) have recently been suggested as an alternative to lead-based halide perovskites for optoelectronic and photovoltaic applications. While a great deal of effort has been put into device engineering to improve the performance of photovoltaic and optoelectronic devices that are based on A2MM'X6 double perovskites, there has been relatively little attention given to their inherent photophysical properties. The current research demonstrates that small polaron formation under photoexcitation and polaron localization limit the carrier dynamics in the Cs2CuSbCl6 double halide perovskite. In addition, temperature-dependent AC conductivity measurements indicate that single polaron hopping is the primary conduction mechanism. The ultrafast transient absorption spectroscopy results revealed that the formation of small polarons, which function as self-trapped states (STSs) and result in the ultrafast trapping of charge carriers, are caused by a distorted lattice under photoexcitation. These findings provide a thorough understanding of the intrinsic restrictions of Cs2CuSbCl6 perovskite and could have relevance for other antimony-based semiconductors.

Modeling by statistical physics and interpretation of the olfactory process of the two enantiomers 3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol on the OR2M3 human olfactory receptor.

In the present paper, a putative adsorption process of two odorants thiols (3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol) on the human olfactory receptor OR2M3 has been investigated via advanced models developed by a grand canonical formalism of statistical physics. For the two olfactory systems, a monolayer model with two types of energy (ML2E) has been selected to correlate with the experimental data. The physicochemical analysis of the statistical physics modeling results showed that the adsorption system of the two odorants was multimolecular. Furthermore, the molar adsorption energies were inferior to 22.7 kJ/mol, which confirmed the physisorption process of the adsorption of the two odorant thiols on OR2M3. In addition, quantitative characterizations of both odorants were determined via the olfactory receptor pore size distribution (RPSD) and the adsorption energy distribution (AED), which were spread out from 0.25 to 1.25 nm and from 5 to 35 kJ/mol, respectively. For thermodynamic characterization of the olfactory process, the adsorption entropy indicated the disorder of the adsorption systems of 3-mercapto-2-methylbutan-1-ol and 3-mercapto-2-methylpentan-1-ol on the human olfactory receptor OR2M3. Besides, the used model showed that the presence of copper ions increases the efficacy (olfactory response at saturation) of 3-mercapt-2-methylpentan-1-ol odorant activating OR2M3. The docking molecular simulation indicated that the 3-mercapto-2-methylpentan-1-ol molecule presented more binding affinities (17.15 kJ/mol) with olfactory receptor OR2M3 than 3-mercapto-2-methylbutan-1-ol (14.64 kJ/mol). On the other hand, the two estimated binding affinities of the two odorants belonged to the adsorption energies spectrum (AED) to confirm the physisorption nature of the olfactory adsorption process.

Adsorption of antibiotics by bentonite-chitosan composite: Phenomenological modeling and physical investigation of the adsorption process.

The increased use of antibiotics worldwide turned into a serious preoccupation due to their environmental and health impacts. Since the majority of antibiotic residuals are hardly eliminated from wastewater, based on usual methods, other treatments receive considerable attention. Adsorption is known as the most effective method of the treatment of antibiotics. In this paper, the adsorption isotherms of doripenem, ampicillin, and amoxicillin on bentonite-chitosan composite are determined at three temperatures, T = 303.15, 313.15 and 323.15 K, which are used to achieve a theoretical investigation of the removal phenomenon, based on a statistical physics theory. Three analytical models are utilized to describe the AMO, AMP, and DOR adsorption phenomena at the molecular level. From the fitting results, all antibiotic adsorption on a BC adsorbent is associated with the monolayer formation with one type of site. Concerning the number of adsorbed molecules per site (n), it is concluded that multi-docking (n < 1) and multi-molecular (n > 1) phenomena are feasible for AMO, AMP, and DOR adsorption on BC. The adsorption amounts at saturation of the BC adsorbent, deduced by the monolayer model, are found to be 70.4-88.0 mg/g for doripenem, 57.8-79.2 mg/g for ampicillin and 38.6-67.5 mg/g for amoxicillin indicating that the antibiotics adsorption performance of BC was greatly depended on temperature where the adsorption capacities increased with the increment of this operating variable. All adsorption systems are demonstrated by a calculation of the energy of adsorption, considering that the extrication of these pollutants implies physical interactions. The thermodynamic interpretation confirms the spontaneous and feasible nature of the adsorption of the three antibiotics on BC adsorbent. In brief, BC sample is regarded as a promising adsorbent to extract antibiotics from water and presents important potentials to be effected in wastewater handling at industrial level.

Influence of VO2 based structures and smart coatings on weather resistance for boosting the thermochromic properties of smart window applications.

Vanadium dioxide (VO2)-based energy-saving smart films or coatings aroused great interest in scientific research and industry due to the reversible crystalline structural transition of VO2 from the monoclinic to tetragonal phase around room temperature, which can induce significant changes in transmittance and reflectance in the infrared (IR) range. However, there are still some obstacles for commercial application of VO2-based films or coatings in our daily life, such as the high phase transition temperature (68 °C), low luminous transmittance, solar modulation ability, and poor environmental stability. Particularly, due to its active nature chemically, VO2 is prone to gradual oxidation, causing deterioration of optical properties during very long life span of windows. In this review, the recent progress in enhancing the thermochromic properties of VO2-hybrid materials especially based on environmental stability has been summarized for the first time in terms of structural modifications such as core-shell structures for nanoparticles and nanorods and thin-films with single layer, layer-by-layer, and sandwich-like structures due to their excellent results for improving environmental stability. Moreover, future development trends have also been presented to promote the goal of commercial production of VO2 smart coatings.

Rational design of (D-A) copolymers towards high efficiency organic solar cells: DFT and TD-DFT study.

In this work, we focus on designing a donor copolymer for the improvement of photovoltaic performance. Using density functional theory and time-dependent density functional theory, we investigated the electronic, optical and charge transfer properties of a series of new designed copolymers based on the reported copolymer Pa0 which is composed of a donor fluorene unit and an acceptor 4,7-dithien-2-yl-2,1,3-benzothiadiazole. We first obtained two copolymers Pb0 and Pc0 by replacing the benzothiadiazole (BTZ) with two different strong acceptors units to decrease the LUMO level of conjugated polymers. Then, we designed Pa1, Pb1 and Pc1 copolymers by adding a substituent methyl group to the thiophene spacer unit (T). Bulk-heterojunction photovoltaic cells were designed with the copolymers as the donors and PCBM as the acceptor. Our results show that the cells based on Pb1 and Pc1 have a suitable electronic structure with energy conversion efficiency exceeding 10%. Moreover, we used Marcus theory to evaluate the intermolecular charge transfer (inter-CT) and recombination (inter-CR) rates of these cells (copolymer/PCBM). The ratio Kinter-CT/Kinter-CR of Pc1/PCBM heterojunction is about 106 times higher than that of Pb1/PCBM which clearly reveals that the designed donor molecule Pc1 will be a promising candidate for high performance organic photovoltaic devices. Our strategy to design novel donor copolymers provides a theoretical guideline for further improving in electrical, optical properties and the efficiency of the photovoltaic device.