- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
New cyclopentadithiophene-based (X-DAD′AD)n conjugated polymers for organic solar cells
摘要： Five new donor-acceptor (X-DAD'AD)n type conjugated polymers have been synthesized using different X blocks based on carbazole, fluorene, silafluorene, benzodithiophene, and cyclopentadithiophene (CPDT). The strongly electron donating CPDT unit was used as a central D′ fragment to enhance intramolecular charge transfer interactions along the polymer backbone and reduce the bandgap of the resulting conjugated polymers. Apparently, the nature of the X block impacts the photophysical, morphological and optoelectronic properties of the designed polymers as well as their performance in bulk heterojunction solar cells. Fluorene-based copolymer P2 in combination with [70]PCBM delivered the best power conversion efficiency of 5.0% with a VOC of 0.78 V, a JSC of 11.1 mA/cm2 and a FF of 57%. Possibility for easy variation of the X and D′ blocks in the designed materials paves a way towards design of a variety of new materials for optoelectronic applications.
关键词： Photovoltaics,Conjugated polymers,Cyclopentadithiophene,Organic solar cells
更新于2025-09-11 14:15:04
-
Self-doping small molecular conjugated electrolytes enabled by n-type side chains for highly efficient non-fullerene polymer solar cells
摘要： We developed a series of novel small molecular conjugated electrolytes (SMCEs) via side chain engineering. The introduced n-type 1,3,4-thiadiazole/1,3,4-oxadiazole side chains featured the related SMCEs with self-doping nature and high electron conductive property. On using as cathode interlayers in non-fullerene-polymer solar cells, a high power conversion efficiency (PCE) of up to 13.21% was achieved with an excellent thickness-insensitive property.
关键词： thickness-insensitive property,side chain engineering,power conversion efficiency,non-fullerene polymer solar cells,small molecular conjugated electrolytes
更新于2025-09-11 14:15:04
-
Side-Chain Engineering of Donor–Acceptor Conjugated Small Molecules As Dopant-Free Hole-Transport Materials for Efficient Normal Planar Perovskite Solar Cells
摘要： Simultaneously improving efficiency and stability, which are particularly crucial factors for the commercialization of perovskite solar cells (PSCs), remains a major challenge. For high efficiency normal PSCs, the development of stable dopant-free hole-transport materials (HTMs) seems imperative. Here, we developed potential donor-acceptor (D-A) small molecules (BTTI) as HTMs for normal planar PSCs. Through tailoring its alkyl side chain length as BTTI-C6, BTTI-C8 and BTTI-C12, our results show that upon shortening the side chain of BTTI, the hole mobility, film-forming capability and resultant device performance were remarkably improved, with device conversion efficiencies of 19.69% for BTTI-C6, 18.89% for BTTI-C8 and 17.49% for BTTI-C12. Meanwhile, compared to those made with the routine doped Spiro-OMeTAD, devices based on our dopant-free HTMs exhibited significantly improved stability. This work paves the way to the development of effective dopant-free HTMs for high performance PSCs.
关键词： Perovskite solar cells,Donor-acceptor conjugated small molecules,Dopant-free,Hole-transport materials,Side chain engineering
更新于2025-09-11 14:15:04
-
Reference Module in Materials Science and Materials Engineering || Excitonic Model versus Band Gap Model in Organic Materials
摘要： The binding energy Eb of an optical excitation is a key parameter for the understanding of the opto-electronic properties of organic solids in general and of conjugated polymers in particular. It controls the dissociation of an electronic excitation of either singlet or triplet character into a pair of free charges as well as the reverse process, i.e., the recombination of an electron–hole (eh) pair yielding an excitation that can decay radiatively or nonradiatively. If Eb is large, photogeneration of charge carriers is an endothermic, inefficient process. It is obvious that in an organic solar cell (OSC) one would like Eb to be as small as possible, while in a light emitting diode (LED) it is the opposite because charge recombination requires a driving force. In this article an outline of the problem of defining the exciton binding in a molecular solid will be presented followed by experimental and theoretical advances and a critical review of relevant conceptual frameworks with particular emphasis on conjugated polymers.
关键词： Organic Materials,Conjugated Polymers,Band Gap Model,Opto-electronic Properties,Exciton Binding Energy
更新于2025-09-11 14:15:04
-
Enhancement of molecular-level ordering of isoindigo based organic materials through deprotecting of cleavable carbamate groups with long alkyl chains
摘要： A new highly soluble isoindigo based organic material with both cleavable carbamate protecting groups bearing long alkyl chains and thiophene groups was successfully synthesized. The carbamate protecting groups were easily removed by solvent-vapor thermal annealing using a mixture of trifluoroacetic acid and chloroform. Deprotection of the NH functional groups in the isoindigo backbone in situ facilitated H-bonding that dramatically improved the strength of the intermolecular interactions. X-ray diffraction and high-voltage electron microscopy studies of the resulting organic material showed long-range ordered crystalline structure. High crystallinity due to enhanced π-π stacking and hydrogen bonding significantly improved the charge carrier mobility. The hole mobilities of isoindigo based organic material measured by SCLC method improved from 3.46 x 10^-6 cm^2 V^-1 s^-1 to 1.13 x 10^-3 cm^2 V^-1 s^-1 upon deprotection of the NH functional groups.
关键词： Isoindigo,Conjugated,Crystallinity,Hydrogen bonding,Protecting groups
更新于2025-09-11 14:15:04
-
The Influence of Moisture on the Energy Level Alignment at the MoO <sub/>3</sub> /Organic Interfaces
摘要： MoO3 is widely used in polymer-based organic solar cells as an anode buffer layer due to its high workfunction and formation of a strong dipole at the MoO3/polymer interface facilitating the charge transfer across the MoO3/polymer interface. In the present work we show that exposure of the MoO3/polymer interface to moisture attracts water molecules to the interface via diffusion. Due to their own strong dipole water molecules counter the dipole at the MoO3/polymer interface. As a consequence, the charge transfer across the MoO3/polymer will reduce and affect the charge transport across the interface. The outcome of this work thus suggest that it is critical to keep the MoO3/polymer interface moisture free which requires special precautions in device fabrications. The composition of the MoO3/P3HT:PC61BM interface is analyzed with X-ray photoelectron spectroscopy and the depth profiling technique neutral impact collision ion scattering spectroscopy. The results show that the concentration of oxygen increases upon exposure but leave the oxidation state of the Mo unchanged. Valence electron spectroscopy technique shows that the dipole across the MoO3/P3HT:PC61BM interface decreases even for short time exposure to atmosphere due to the diffusion of water molecules to the interface. The far-ranging consequences for organic electronic devices are discussed.
关键词： exposure to air,interface,dipole formation,electron spectroscopy,metal oxide,organic photovoltaic,conjugated polymer
更新于2025-09-11 14:15:04
-
Pd2+-conjugated reduced graphene oxide as a highly efficient visible-light-induced photocatalytic Suzuki-Miyaura coupling
摘要： In this work, we investigated Pd2+- and Pd0-loaded graphene oxide (GO) and reduced graphene oxide (r-GO) as water-soluble, visible-light-responsive photocatalysts for the Suzuki-Miyaura C-C coupling reaction. Nanosheets of r-GO (~ 200 nm) were found to be a more desirable substrate than GO nanosheets, since the corresponding catalyst showed higher activities than those of the GO catalysts in both the visible-light-induced and thermal-reactions. Furthermore, Pd2+-loaded GO and r-GO show higher catalytic activities than those of Pd0-loaded GO and r-GO because of the more efficient oxidative addition to Pd2+ compared with that to Pd0. Systematic studies under dark and light conditions demonstrated the synergic contributions of photoexcited electron transfer and the strong photothermal effect of r-GO. Pd2+- and Pd0-loaded r-GO show four-times higher photocatalytic activities compared to those of Pd0-MoS2 and Pd0-WS2 catalysts for the Suzuki-Miyaura C-C coupling reaction.
关键词： Suzuki-Miyaura coupling,reduced graphene oxide,Pd2+-conjugated reduced graphene oxide,graphene oxide,visible-light-induced photocatalytic
更新于2025-09-10 09:29:36
-
Effect of Linking Pattern of Dibenzothiophene- <i>S</i> , <i>S</i> -dioxide-Containing Conjugated Microporous Polymers on the Photocatalytic Performance
摘要： Conjugated microporous polymers (CMPs) exhibit great potential for photocatalytic hydrogen generation due to their tunable electronic structure. The rational molecular design is a key point for developing an efficient CMP photocatalyst. Herein, we developed two CMPs photocatalysts via the copolymerization from pyrene and dibenzothiophene-S,S-dioxide building blocks. The effect of the linking pattern of the building block of dibenzothiophene-S,S-dioxide on the photocatalytic hydrogen evolution was explored. The polymer of PyDOBT-1 with 3,7-linking pattern shows a superior photocatalytic performance to PyDOBT-2 with 2,8-linking pattern because the 3,7-linking pattern enhances the conjugation chain length and improves the coplanarity of the polymeric backbone, which facilitate the charges migration along the polymer chain. As a result, the bare PyDOBT-1 shows an impressive visible light activity with a hydrogen evolution rate (HER) of 5697 μmol h?1 g?1. Notably, an outstanding HER of 12986 μmol h?1 g?1 was also obtained by the Pt-modified PyDOBT-1 under the full-arc spectrum (λ > 300 nm), which lies toward the upper end compared to that of the reported organic photocatalysts.
关键词： Conjugated microporous polymers,Dibenzothiophene-S,S-dioxide,Photocatalytic hydrogen generation,Linking pattern,Hydrogen evolution rate
更新于2025-09-10 09:29:36
-
Understanding structure-activity relationships in linear polymer photocatalysts for hydrogen evolution
摘要： Conjugated polymers have sparked much interest as photocatalysts for hydrogen production. However, beyond basic considerations such as spectral absorption, the factors that dictate their photocatalytic activity are poorly understood. Here we investigate a series of linear conjugated polymers with external quantum efficiencies for hydrogen production between 0.4 and 11.6%. We monitor the generation of the photoactive species from femtoseconds to seconds after light absorption using transient spectroscopy and correlate their yield with the measured photocatalytic activity. Experiments coupled with modeling suggest that the localization of water around the polymer chain due to the incorporation of sulfone groups into an otherwise hydrophobic backbone is crucial for charge generation. Calculations of solution redox potentials and charge transfer free energies demonstrate that electron transfer from the sacrificial donor becomes thermodynamically favored as a result of the more polar local environment, leading to the production of long-lived electrons in these amphiphilic polymers.
关键词： photocatalysts,transient spectroscopy,hydrogen production,sulfone groups,conjugated polymers
更新于2025-09-10 09:29:36
-
Novel Functional TPE Polymers: Aggregation-Induced Emission, pH Response, and Solvatochromic Behavior
摘要： Four tetraphenylethylene (TPE)-based aryleneethynylene polymers with amino or nitro groups are reported. They display strong aggregation-induced emission (AIE). The functional groups trigger acidochromic changes in the emission behavior of these polymers. Amino-substituted P1–P3 exhibit pH response through protonation of the amino groups. The position of the amino groups (on TPE or the side chains) influences the fluorescence intensity or emission wavelength as a response to different pH values. Nitro-P4 is solvatochromic due to its donor–acceptor structure. AIE, intramolecular charge transfer, and F?rster resonance energy transfer define the fluorescence-based performance of the polymers. The amino-functionalized TPE polymers show excellent nitroarene-sensing performance. P4 is less effective than the amino polymers. A sensor array based on P1–P3 identifies 12 different nitroarenes in water.
关键词： selectivity,fluorescence,conjugated polymers,modification
更新于2025-09-10 09:29:36