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Efficient Polymer Solar Cells Based on New Random Copolymers with Porphyrin‐Incorporated Side Chains
摘要： Two new wide bandgap block copolymers (PL1 and PL2) with porphyrin-incorporated side chains are designed and used as electron donors for solution-processed bulk heterojunction polymer solar cells. The photophysical, electrochemical, and photovoltaic properties, charge transport mobility and film morphology of these two block copolymers are investigated. Detailed investigations reveal that the different alkyl groups and electron-withdrawing substituents on the porphyrin pendant units have significant influence on the polymer solubility, absorption energy level, band gap, and charge separation in the bulk-heterojunction thin films, and thus the overall photovoltaic performances. Organic photovoltaic devices derived from these copolymers and ([6,6]-phenyl-C71-butyric acid methyl ester) (PC71BM) acceptor show the best power conversion efficiencies of 5.83% and 7.14%, respectively. These results show that the inclusion of a certain proportion of side chain porphyrin group as a pendant in the traditional donor-acceptor (D-A) type polymer can broaden the molecular absorption range and become a full-color absorbing molecule. The size of the porphyrin pendant also has an obvious effect on the properties of the molecule.
关键词： block copolymers,organic photovoltaics,polymer solar cells,bulk heterojunctions,porphyrin
更新于2025-09-11 14:15:04
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Reversibly Photoswitchable Dual-Color Fluorescence and Controlled Release Properties of Polymeric Nanoparticles
摘要： Here, we report a novel polymeric nanoparticle prepared by the self-assembly of amphiphilic copolymers containing a ?uorescent naphthalimide (NAPH) and a photochromic spiropyran (SP), which possesses reversibly photoswitchable dual-color ?uorescence and controlled release properties. The amphiphilic copolymers were synthesized by incorporating NAPH and SP into methyl ether poly(ethylene glycol)-poly(β-amino esters) (MPEG-PAE) via quaternization. The nanoparticles would change between yellow and purple reversibly upon UV and visible light irradiation because of the photoisomerization between SP and merocyanine (MC). The corresponding ?uorescence would be switched between green and orange-red reversibly upon blue light excitation through the ?uorescence resonance energy transfer from the excited NAPH to the photoisomerized MC. Meanwhile, the prepared spherical nanoparticles could be swollen under UV irradiation as the hydrophobic SP isomerized to hydrophilic MC; the nanoparticles could also be swollen under acidic conditions because of the protonation of the amino groups of PAE. Upon UV light irradiation and acidic stimulation, the cargoes, hydrophobic Coumarin 102, encapsulated in the nanoparticles would be released. The prepared nanoparticles, which exhibit not only excellent reversible dual-color ?uorescence properties but also prominent controlled release performance, will open up new possibilities for the combined application of ?uorescence imaging and controlled release.
关键词： naphthalimide,Coumarin 102,spiropyran,polymeric nanoparticles,photoswitchable,amphiphilic copolymers,acidic conditions,quaternization,self-assembly,FRET,UV/vis light irradiation,dual-color ?uorescence,MPEG-PAE,controlled release
更新于2025-09-11 14:15:04
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Low-bandgap D-A1-D-A2 type copolymers based on TPTI unit for efficient fullerene and nonfullerene polymer solar cells
摘要： To obtain low-bandgap polymers paired well with fullerene and nonfullerene acceptors, here we adopted a D-A1-D-A2 motif to develop two new low-bandgap copolymers PTPTI-T-BDD and PTPTI-T-FBT, where thiophene was used as the D unit, thieno[2,3-b:5,6-b′]pyrido[3,4-g]thieno[3,2-c]-isoquinoline-5,11(4H,10H)-dione (TPTI) was used as the A1 unit, and benzo[1,2-b:4,5-b′]dithiophene-4,8-dione (BDD) and 5,6-difluoro-2,1,3-benzothiadiazole (FBT) were employed as the A2 unit, respectively. Effects of the electron-withdrawing strength of A2 unit on optoelectronic and photovoltaic properties of the PTPTI-T-BDD- and PTPTI-T-FBT-based fullerene and nonfullerene polymer solar cells (PSCs) were systematically investigated. When blended with PC71BM and ITIC, PTPTI-T-FBT-based PSCs showed a power conversion efficiency (PCE) of 6.20% and 6.03%, respectively, both of which are higher than that of PTPTI-T-BDD-based PSCs. Furthermore, ternary PSCs based on PBDB-T:PTPTI-T-FBT:PC71BM exhibited an improved PCE of 7.92%. This work suggests that constructing D-A1-D-A2 copolymers is a promising strategy to develop low-bandgap copolymers for efficient fullerene and nonfullerene PSCs with a reduced energy loss.
关键词： D-A1-D-A2 copolymers,TPTI,Fullerene and nonfullerene PSCs
更新于2025-09-11 14:15:04
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Synthesis of Alkoxyacene‐Based Random Copolymers and Binary Solvent Additive for High Efficiency Organic Photovoltaics
摘要： The synthesis of three random copolymers—BD2FON-OB30, BD2FON-OB50, and BD2FON-OB70—comprised of different molar ratios of alkoxyphenylene and alkoxynaphthalene is reported by adjusting the ratio of these units for optimized energy levels. When organic photovoltaics are fabricated using these polymers as the electron donor, introduction of the binary solvent additive dramatically enhances power conversion efficiency (PCE) up to 7%, compared to those of the devices without additive (≈2% of PCEmax) and with single additive (≈3% of PCEmax). (without additive: 1–2% and with single additive: 0–3%). These improvements result from minimized bimolecular recombination and balanced electron/hole mobility ratio by optimized bicontinuous D:A morphology in the active layer. Thus, the strategy shows the efficient enhancement of device efficiency by control the morphology using binary solvent additives in the bulk heterojunction film consisting of polymer and fullerene.
关键词： binary solvent additives,organic photovoltaics,random copolymers
更新于2025-09-11 14:15:04
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Precise Synthesis of Ultra-High-Molecular-Weight Fluoropolymers Enabled by Chain-Transfer Agent Differentiation under Visible-Light Irradiation
摘要： A photo-mediated reversible-deactivation radical polymerization has been developed based on a novel chain-transfer agent (CTAs) differentiation mechanism, enabling the precise preparation of fluoropolymers with ultra-high molecular weights, narrow molecular weight distributions and excellent chain-end fidelity at complete conversions. Moreover, this synthetic approach is efficient, scalable, temporally controllable and compatible to a variety of monomers and CTAs.
关键词： block copolymers,photochemistry,polymerization,synthetic methods,fluorine
更新于2025-09-11 14:15:04
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Toxic Solvent‐ and Additive‐Free Efficient All‐Polymer Solar Cells via a Simple Random Sequence Strategy in Both Donor and Acceptor Copolymer Backbones
摘要： It is extremely important to develop nontoxic solvent and additive-processed high-performance all-polymer solar cells (all-PSCs) that are suitable for printing preparation of large-scale devices. Herein, it is demonstrates that a simple random copolymerization of two acceptor monomers (benzo[1,2-c:4,5-c′]dithiophene-4,8-dione (BDD) and 5,6-difluoro-2H-benzo[d][1,2,3] triazole (FTAZ)), alternating with Si atom-containing benzo[1,2-b:4,5-b′] dithiophene donor comonomer, forms a successful approach by which to synthesize donor copolymers with excellent solubility/processability for nontoxic-solvent-processed all-PSCs. The incorporation of a higher degree of BDD in the backbone lowers the frontier energy levels, as well as redshifts, with higher absorption coefficients; however, it adversely affects solubility in a 2-methyltetrahydrofuran (MeTHF). An impressive power conversion efficiency, of about 8.0%, is achieved from PJ25 (25 mol% BDD)-based all-PSC when paired with N2200-F30 acceptor random copolymer by using MeTHF as the processing solvent without any additive. Another interesting point is that the air stability of the all-PSCs increases with increasing FTAZ content due to strong noncovalent interaction and resistance to humidity and oxidation caused by the F-atoms in FTAZ units. Not only does this study establish a structure–property–performance relationship through a series of structural, morphological, and electrical characterization techniques, but it also provides a promising and easy way to develop nontoxic-solvent-processed high-performance all-PSCs.
关键词： compatibility,nontoxic solvents,random copolymers,additive-free processing,all-polymer solar cells
更新于2025-09-11 14:15:04
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Electrostatic Interaction Mediates the Formation of Vesicular Structures from Coassembly of PS- <i>b</i> -PAA with Quantum Dots
摘要： Vesicular structures of block copolymers and inorganic nanoparticles with good stability have potential applications in therapeutic drug release and bioimaging. Herein, a block copolymer of polystyrene-b-poly(acrylic acid) (PS48-b-PAA67) and water-soluble AgInS2/ZnS core/shell quantum dots (QDs) capped with gelatin and thioglycolic acid were coassembled in tetrahydrofuran by adding water. The positively charged QDs bind to negatively charged PAA segments through electrostatic interaction. Numerous vesicular structures, such as uniform bilayer vesicles, ?owerlike large compound vesicles, onionlike lamellar structures consisting of alternating PS and PAA&QD layers, and multilamellar vesicles with spaces between concentric vesicle layers were obtained from the coassembly of PS48-b-PAA67 with QDs. The binding of the positively charged QDs to the PAA block in?uenced both the intra-aggregate PAA corona conformation and the interaggregate interactions. The key parameters a?ecting the formation of these vesicular structures included the QD content, solution pH, and water addition rate. Thus, tunable vesicular structures can be prepared and regulated through this simple but e?ective coassembly method.
关键词： electrostatic interaction,vesicular structures,quantum dots,coassembly,block copolymers
更新于2025-09-11 14:15:04
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Enhanced Hybridization and Nanopatterning via Heated Liquid-Phase Infiltration into Self-Assembled Block Copolymer Thin Films
摘要： Organic-inorganic hybrids featuring tunable material properties can be readily generated by applying vapor- or liquid-phase infiltration (VPI or LPI) of inorganic materials into organic templates, with resulting properties controlled by type and quantity of infiltrated inorganics. While LPI offers more diverse choices of infiltratable elements, it tends to yield smaller infiltration amount than VPI, but the attempt to address the issue has been rarely reported. Here, we demonstrate facile temperature-enhanced LPI method to control and drastically increase the quantity and kinetics of Pt infiltration into self-assembled polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer (BCP) thin films. By applying LPI at mildly elevated temperatures (40 – 80 °C), we showcase controllable optical functionality of hybrid BCP films along with conductive three-dimensional (3D) inorganic nanostructures. Structural analysis reveals enhanced metal loading into BCP matrix at higher LPI temperatures, suggesting multiple metal ion infiltration per monomer of P2VP. Combining temperature-enhanced LPI with hierarchical multilayer BCP self-assembly, we generate BCP-metal hybrid optical coatings featuring tunable antireflective properties as well as scalable conductive 3D Pt nanomesh structures. Enhanced material infiltration and control by temperature-enhanced LPI not only enables tunability of organic-inorganic hybrid nanostructure and properties but also expands the application of BCPs for generating uniquely functional inorganic nanostructures.
关键词： self-assembled block copolymers,hybrid thin film,optical coating,Pt nanomesh,Liquid-phase infiltration
更新于2025-09-11 14:15:04
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Effect of Electron-Acceptor Content on the Efficiency of Regioregular Double-Cable Thiophene Copolymers in Single-Material Organic Solar Cells
摘要： Three regioregular thiophenic copolymers, characterized by a bromine atom or a C60-fullerene group at different molar ratios at the end of a decamethylenic plastifying side chain, have been successfully synthesized using a straightforward postpolymerization functionalization procedure based on a Grignard coupling reaction. Owing to their good solubility in common organic solvents, the products were fully characterized using chromatographic, spectroscopic, thermal, and morphological techniques and used as single materials in the photoactive layers of organic solar cells. The photoconversion efficiencies obtained with copolymers were compared with those of a reference cell prepared using a physical blend of the precursor homopolymer and [6,6]-phenyl-C61-butyric acid methyl ester. The best results were obtained with COP2, the copolymer with a 21% molar content of C60-functionalized side chains. The use of the double-cable polymer made possible an enhanced control on the nanomorphology of the active blend, thus reducing phase-segregation phenomena as well as the macroscale separation between the electron-acceptor and -donor components, yielding a power conversion efficiency higher than that of the reference cell (4.05 vs 3.68%). Moreover, the presence of the halogen group was exploited for the photo-cross-linking of the active layer immediately after the thermal annealing procedure. The cross-linked samples showed an increased stability over time, leading to good efficiencies even after 120 h of accelerated aging: this was a key feature for the widespread practical applicability of the prepared devices.
关键词： photo-cross-linking,C60-fullerene,double-cable polymer,thermal annealing,regioregular thiophenic copolymers,Grignard coupling reaction,organic solar cells,photoconversion efficiencies
更新于2025-09-11 14:15:04
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Solubility and H-bonding of poly(vinylidene fluoride) copolymers in carbonyl liquids: Experiment and molecular simulation
摘要： H-bond formation among fluoropolymers and carbonyl solvents was studied by microcalorimetry and quantum chemistry simulation. Typically, fluorine atoms in organic molecules depress their ability to molecular interactions with solvents. Meanwhile, it is not the case if fluoropolymer is dissolved in carbonyl solvent. Among other organic solvents carbonyl-containing liquids are characterized by very large exothermic effects of dissolution of vinylidene fluoride copolymers which are typical for the systems with electron-donor-acceptor complexes. The enthalpy of mixing in the entire concentration range was determined for P(VDF-co-HFP) and P(VDF-co-CTFE) solutions in ethyl acetate and Flory-Huggins parameter was evaluated. It was ?1.31, which means very strong interaction among solvent and vinylidene fluoride monomer units. This interaction was modeled by quantum chemistry semi-empirical AM1, PM3, PM5 and density functional B88-PW91, B88-LYP, D-VWN calculations for the complexes between acetone or ethyl acetate and vinylidene fluoride tetramer. The heat of formation of the complex from its components was found around ?18 kJ/mol. The binding site of the complex was a macrocyclic structure which comprised H-bonds between carbonyl and methylene hydrogens of vinylidene fluoride backbone, and weaker H-bonds between fluorine atoms and methyl hydrogen. The analysis of molecular orbitals of the complex reveals extended electron delocalization across the binding center.
关键词： Calorimetry,H-bonding,Computer modeling,Solubility of vinylidene fluoride copolymers
更新于2025-09-10 09:29:36