Elimination of Pharmaceutical Compounds from Aqueous Solution through Novel Functionalized Pitch-Based Porous Adsorbents: Kinetic, Isotherm, Thermodynamic Studies and Mechanism Analysis.

The long-term presence of PPCPs in the aqueous environment poses a potentially significant threat to human life and physical health and the safety of the water environment. In our previous work, we investigated low-cost pitch-based HCP adsorbents with an excellent adsorption capacity and magnetic responsiveness through a simple one-step Friedel-Crafts reaction. In this work, we further investigated the adsorption behavior of the prepared pitch-based adsorbents onto three PPCP molecules (DFS, AMP, and antipyrine) in detail. The maximum adsorption capacity of P-MPHCP for DFS was 444.93 mg g-1. The adsorption equilibrium and kinetic processes were well described through the Langmuir model and the proposed secondary kinetic model. The negative changes in Gibbs free energy and enthalpy reflected that the adsorption of HCPs onto PPCPs was a spontaneous exothermic process. The recoverability results showed that the adsorption of MPHCP and P-MPHCP onto DFS remained above 95% after 10 adsorption-desorption cycles. The present work further demonstrates that these pitch-based adsorbents can be used for multiple applications, which have a very extensive practical application prospect.

Synthesis of novel magnetic pitch-based hypercrosslinked polymers as adsorbents for effective recovery of Ag+ with high selectivity.

Silver is an important precious metal with superior ductility, electrical and thermal conductivity, photosensitivity, and antibacterial properties. However, without proper recycling and treatment, silver emissions may pose a threat to the human health and subsistence environment due to their toxicity. Therefore, it is environmentally and economically important to recover Ag from waste electronic equipment and anode slime. Herein, carboxyl functionalized modified magnetic nanoparticles (Fe3O4@3-phenylglutaricacid nanoparticles) were designed and prepared to obtain the low-cost magnetic pitch-based HCP adsorbents (MPHCP and P-MPHCP). The novelty of present work is that superior adsorption capacity and magnetic responsiveness of adsorbent can be obtained by a simple one-step Friedel-Crafts reaction with very low-cost raw material. The maximum Ag+ adsorption capacity of MPHCP and P-MPHCP were 321 and 353 mg/g, respectively. The adsorption was completed within a short duration of 15 min for MPHCP and P-MPHCP at an initial Ag+ concentration of 100 mg/L. Moreover, the most selective is P-MPHCP wherein Ag+ is α = 61 times more selective than Pb2+ at a concentration of 100 mg/L.The adsorption capacity of MPHCP and P-MPHCP towards Ag+ still maintains above 89% after ten cycles of adsorption-desorption. This study not only provides new guidance for the development of porous polymeric adsorbents but also provides technical feasibility for the field of recovery and reutilization of precious metals, which has a very extensive practical application prospect.

Decreased domain size of p-DTS(FBTTh2)2/P(NDI2OD-T2) blend films due to their different solution aggregation behavior at different temperatures.

Nanoscale interpenetrating networks play a key role in determining the optoelectrical properties of functional blends. However, phase separated large domain sizes could probably be observed in pristine films composed of two crystalline components. For example, p-DTS(FBTTh2)2/P(NDI2OD-T2) 3/2 blend films with interpenetrating networks are obtained, however, large domain sizes are found when they are prepared from a 20 °C solution due to the simultaneous process of crystallization and phase separation during solvent evaporation. In this paper, we proposed to reduce the domain size of p-DTS(FBTTh2)2/P(NDI2OD-T2) blend films using their different solution aggregation behaviors at different temperatures. The aggregation of p-DTS(FBTTh2)2 molecules in chlorobenzene (CB) was insensitive to the solution temperature. However, the in situ absorption spectra of the neat P(NDI2OD-T2) solution from 80 °C to room temperature indicated that P(NDI2OD-T2) aggregation increased with decreasing temperature due to intrachain interactions. Therefore, in order to reduce the domain size, we employed a hot solution to prepare the blend films. During the solidification process, the majority of p-DTS(FBTTh2)2 molecules were confined in the P(NDI2OD-T2) networks prior to occurrence of severe p-DTS(FBTTh2)2 aggregation. Thus, the domain size of the p-DTS(FBTTh2)2 phase became smaller than that of the pristine films, leading to a decrease in the corresponding photoluminescence intensity of the blend films. In addition, the crystallinity of the blend films improved after thermal annealing, which resulted from the ordered alignment of p-DTS(FBTTh2)2 molecules facilitated by their enhanced diffusion ability. Based on the various morphologies, a possible phase diagram of the p-DTS(FBTTh2)2/P(NDI2OD-T2) blend system was depicted, which could be a guide to directly control the morphology of blend films.

Achieving balanced intermixed and pure crystalline phases in PDI-based non-fullerene organic solar cells via selective solvent additives.

Herein, balanced intermixed and pure crystalline phases in N,N'-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (EP-PDI)-based non-fullerene organic solar cells (OSCs) were achieved via selective solvent additives (SAs). Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) and 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole) (F-DTS) possessing different compatibilities with EP-PDI were selected as model systems to investigate the guideline of SAs selection for different non-fullerene-based systems. According to the solubility parameter difference (Δδ) between EP-PDI and SAs, five different SAs were divided into two types: (I) strong intermolecular interactions with EP-PDI molecules (with Δδ values less than 5 MPa(1/2)), (II) weak intermolecular interactions with EP-PDI molecules (with large Δδ values). For PTB7:EP-PDI system with large and obvious phase separation, the introduction of type (II) SAs provided extra interactions with EP-PDI molecules, thus effectively reducing EP-PDI aggregate domains and increasing intermixed fractions. The incorporation of type (II) SAs resulted in a greater yield of dissociated polarons, and the final device efficiency increased from 0.02% to 1.65%. On the contrary, for finely mixed F-DTS:EP-PDI systems, type (I) SAs were considerably more effective because of the fact that the required pure crystalline phases were readily induced by the unfavorable interactions. The charge transport pathways optimized by type (I) SAs improved device efficiency from 0.18% to 2.82%. Hence, by processing selective SAs, the fraction of intermixed and pure crystalline phases for PDI-based non-fullerene OSCs can be well regulated; therefore, the final performance for both systems can be significantly improved.

High-Quality Hybrid Perovskite Thin Films by Post-Treatment Technologies in Photovoltaic Applications.

Incredible progress in photovoltaic devices based on hybrid perovskite materials has been made in the past few decades, and a record-certified power conversion efficiency (PCE) of over 26% has been achieved in single-junction perovskite solar cells (PSCs). In the fabrication of high-efficiency PSCs, the postprocessing procedures toward perovskites are essential for designing high-quality perovskite thin films; developing efficient and reliable post-treatment techniques is very important to promote the progress of PSCs. Here, recent post-treatment technological reforms toward perovskite thin films are summarized, and the principal functions of the post-treatment strategies on the design of high-quality perovskite films have been thoroughly analyzed by dividing into two categories in this review: thermal annealing (TA)-related technique and TA-free technique. The latest research progress of the above two types of post-treatment techniques is summarized and discussed, focusing on the optimization of postprocessing conditions, the regulation of perovskite qualities, and the enhancement of device performance. Finally, an outlook of the prospect trends and future challenges for the fabrication of the perovskite layer and the production of highly efficient PSCs is given.

Surface Reconstruction via Molten Chloride Salt for Efficient and Stable Perovskite Solar Cells.

Perovskite solar cells (PSCs) have attracted significant attention due to their high efficiencies that are closely associated with the optimized interface of perovskite (PVK) films. However, during film deposition, tremendous interfacial defects are generated in PVK films, which suppress device performance. Herein, we employ an organic molten chloride salt of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) on the PVK surface to regulate the interface properties through surface reconstruction by heating to 110 °C, during which DMTMM undergoes an obvious phase transition from a solid to liquid molten salt. The mobile phase coordinates with unsaturated Pb2+ and halide vacancies to heal the structural defects. After the mixture cools to room temperature, a compact DMTMM interlayer is formed to protect PVKs from degradation in the air. Consequently, the DMTMM-treated MAPbI3-based PSCs yield a champion PCE approaching 20% with optimized stability. This molten-salt-assisted surface reconstruction strategy provides a new approach to establish highly stable hybrid perovskite films for high-performance PSCs.

Crystallization of D-A Conjugated Polymers: A Review of Recent Research.

D-A conjugated polymers are key materials for organic solar cells and organic thin-film transistors, and their film structure is one of the most important factors in determining device performance. The formation of film structure largely depends on the crystallization process, but the crystallization of D-A conjugated polymers is not well understood. In this review, we attempted to achieve a clearer understanding of the crystallization of D-A conjugated polymers. We first summarized the features of D-A conjugated polymers, which can affect their crystallization process. Then, the crystallization process of D-A conjugated polymers was discussed, including the possible chain conformations in the solution as well as the nucleation and growth processes. After that, the crystal structure of D-A conjugated polymers, including the molecular orientation and polymorphism, was reviewed. We proposed that the nucleation process and the orientation of the nuclei on the substrate are critical for the crystal structure. Finally, we summarized the possible crystal morphologies of D-A conjugated polymers and explained their formation process in terms of nucleation and growth processes. This review provides fundamental knowledge on how to manipulate the crystallization process of D-A conjugated polymers to regulate their film structure.

Enhancing Built-in Electric Field via Molecular Dipole Control in Conjugated Microporous Polymers for Boosting Charge Separation.

The built-in electric field (BEF) has been considered as the key kinetic factor for facilitating efficient photoinduced carrier separation and migration of polymeric photocatalysts. Enhancing the BEF of the polymers could enable a directional migration of the photogenerated carriers to accelerate photogenerated charge separation and thus boost photocatalytic performances. However, achieving this approach remains a formidable challenge, which has never been realized in conjugated microporous polymers (CMPs). Herein, we developed a molecular dipole control strategy to modulate the BEF in CMPs by varying the nature of the core. As a result, a series of CMPs with a tunable BEF were designed and prepared via FeCl3-mediated coupling of bicarbazole with different acceptor cores. The optimized CbzCMP-9 featured the strongest BEF induced by its high molecular dipole, which grants it with a powerful driving force to accelerate exciton dissociation into electron-hole pairs and facilitates charge transfer along the backbone of CMPs to the surface, resulting in a remarkable photocatalytic performance toward thiocyano chromones and C-3 thiocyanation of indoles (up to 95 and 98% yields, respectively) and prominently surpassing many other reported photocatalysts. In brief, the proposed strategy highlights that enhancing the BEF by modulating molecular dipole can lead to a dramatic improvement in photocatalytic performance, which is expected to be employed for constructing other photocatalytic systems with high performance.