SYNTHETIC METALS
·
2013
·
IF 2.109
Hangqi Shi,Zhuowei Gu,Xiao Gu,Hongbin Pan,Junying Pan,Xiaolian Hu,Congcheng Fan,Minmin Shi,Hongzheng Chen
In this work, a diphenyl substituted diketopyrrolopyrrole (DPP) and its two derivatives end-capped with fluorine and n -butyl respectively, namely PDPPP, FPDPPPF, and RPDPPPR, are designed and synthesized. The resulting molecules exhibit similar energy structures, i.e. both relatively narrow optical band gaps (1.75–1.79 eV) and deep highest occupied molecular orbital (HOMO) energy levels (−5.18 to −5.25 eV), implying that all of them are potentially good electron donors for organic solar cells (OSCs). However, three molecules show different photovoltaic performances when they are blended with [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM) to fabricate OSCs: the RPDPPPR-based device gives the highest power conversion efficiency (PCE) of 1.59%, whereas the PCEs of PDPPP and FPDPPPF-based OSCs are 0.46% and 0.55%, respectively. Through atomic force microscopy (AFM), X-ray diffraction (XRD) and space charge limited current (SCLC) characterizations, the prominent role of end-groups in the photovoltaic properties of DPP derivatives is disclosed: terminal alkyl chains in RPDPPPR can promote molecular crystallization and lead to the formation of finer phase-separation domains in the blended film, which are in favor of charge generation and transportation in the photovoltaic devices. Thus, RPDPPPR provides the best photovoltaic property among three DPP molecules.
研究领域:
材料科学
·
有机电子学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Huijun Xu,Ao Feng,Zhihao Huang,Rui Tan,Zefan Wang,Xiaohua Zhang,Zhengbiao Zhang
Discrete oligomers are ideal candidates for the investigation of the crystallization behaviors of polymers since the molecular weight distribution and the precision of molecular structures play a crucial role in the crystallization behaviors of polymers. We precisely synthesize discrete alternative co-oligomers (o(γ-BL-alt-ε-CL)s) with different end groups based on ε-caprolactone (ε-CL) and γ-butyrolactone (γ-BL) as monomers using an iterative exponential growth (IEG) strategy and systematically study the crystallization and melting behaviors of the o(γ-BL-alt-ε-CL)s with precise monomer sequence. The roles that the end group plays in the crystallization and melting of co-oligomers are highlighted. The o(γ-BL-alt-ε-CL)s with different end groups (tert-butyldiphenylsilyl, benzoyl, acetyl) crystallize in an extended-chain conformation. Observation on the decrease of the crystallization rate of co-oligomers with the increase of the size of the end groups is associated with the slow dynamics or slow relaxation of co-oligomer chains with the large end group. The melting–recrystallization during the heating process for the o(γ-BL-alt-ε-CL)s with small end group is attributed primarily to the reduced steric hindrance effect. For the o(γ-BL-alt-ε-CL)s with large end groups, the rearrangement of co-oligomer chains is substantially hindered by steric effects, which lead to a significant suppression of the melting–recrystallization.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Yuchun Huang,Yujian Liu,Saleem Muhammad,Qun Jia,Yuansheng Ding,Yougen Chen
The present work describes the detailed macromolecular design, synthesis, and characterization of a series of mono- and bi-terminal functionalized polystyrenes (PSs) by the combination of atom transfer radical polymerization (ATRP) and copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. We further study the effect of the incorporated end groups on the glass transition behavior of the resulting polymers. The mono and bi functionalized polystyrenes were synthesized by using 1-phenylethyl bromide and 1,4-bis(bromomethyl)benzene as the initiators to form bromo mono-end functionalized PS (PS-Br) and bromo bi-terminal functionalized PS (Br-PS-Br), respectively. PS-Br and Br-PS-Br were then transformed to azido mono- and bi-terminal functionalized PSs (PS-N 3 and N 3 -PS-N 3 ) by S N 2-type reaction with sodium azide . PS-N 3 and N 3 -PS-N 3 were then subjected to CuAAC reactions with various alkynes like 1-decyne, 1-hexyne, trimethylsilylacetylene, phenylacetylene , and 4-ethynyl-1,1′-biphenyl respectively to give a series of alkyl or aromatic mono- and bi-terminal functionalized PSs (PS-Rs and R-PS-Rs), such as PS-Rs of PS-C 8 H 17 , PS-C 4 H 9 , PS-SiMe 3 , PS-Ph, PS-biPh, and R-PS-Rs of C 8 H 17 -PS-C 8 H 17 , C 4 H 9 -PS-C 4 H 9 , SiMe 3 -PS-SiMe 3 , Ph-PS-Ph, and biPh-PS-biPh. PS-SiMe 3 and SiMe 3 -PS-SiMe 3 were then transformed to the corresponding PS-H and H-PS-H through the detrimetylsilylation reaction with tetra- n -butylammonium fluoride (TBAF). Among the five end groups, -C 8 H 17 and -C 4 H 9 were with great flexibility; -H was viewed as a standard; and -Ph and -biPh groups represented the typical rigid moieties. The effect of these end groups on glass transition behavior was thoroughly investigated based on the above macromolecular design.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 44
·35282-35290
·
IF 3.84
Si Chen,Guodong Tang,Bozhen Wu,Meng Ma,Xu Wang
The key effect of the self-assembly mechanism of dendritic gelators is researched by a comprehensive investigation of the gelation behavior of L-lysine dendritic gelators with different structures of three generations in 20 different solvents. The solvents investigation, 1H NMR, tube inversion method, DSC, rheology, FTIR and rheological measurements show that the reported dendritic gelators self-assemble through the main driving force of hydrogen bonds and the second driving force of π–π stackings. So the key effect of the self-assembling mechanism is that these factors can influence the driving force of the self-assembly process. This is the reason that L-lysine dendritic gelators tend to gelate in solvents with low α and β parameter values, which have less influence on the formation of hydrogen bonds between the gelators. Higher generations provide a much greater hydrogen bond density in the gelators, which makes them have a higher gelation ability. The benzyl terminal groups provide the second driving force of π–π stacking, making the Bzl-Gly-Lys gelators have much stronger gelation ability. This research reports a comprehensive insight into the precise ways in which the solubility parameters of the solvents, the gelator generation and the terminal group effects can influence the self-assembly and gelation of dendritic gelators. Gaining this type of fundamental understanding is essential if the key effect of this important class of self-assembling soft materials is to be truly understood.
研究领域:
材料科学
·
化学
·
纳米技术
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Shaoguang Li,Yuanyuan Wang,Zishuo Zhang,Yiming Wang,Hui Li,Fan Xia
The continuous, real-time monitoring of specific analytes in situ in biological fluids would provide personalized, high-precision pharmacokinetic information for the goal of precision medicine. Due to their conformationally linked signaling mechanism, electrochemical aptamer-based (E-AB) sensors are promising candidates for accurate measurements in such complex media. They suffer, however, from severe baseline drift when interrogated continuously and in real-time manner. In response, here, we investigate a couple of self-assembled monolayers in the application of E-AB sensors, achieving the improvement of their baseline stability and simultaneous modulation of sensor performance, e.g., target affinity and specificity.
研究领域:
分析化学
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生物传感器
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电化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）