Effect of permodified β-cyclodextrin on the photophysical properties of poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene)] main chain polyrotaxanes

Abstract

The photophysical properties of two polyrotaxanes (PFBTh•PSbCD and PFBTh•PMebCD) composed of fluorene and bithiophene encapsulated into permodified b-cyclodextrin cavities have been investigated and compared with those of the reference PFBTh. Rotaxane formation results in improvements of the thermal stability, solubility in common organic solvents, as well as better film forming ability combined with a high transparency. As expected PFBTh and its encapsulated forms absorb at wavelengths beyond 510 nm, and time-resolved photoluminescence (PL) in solution shows a well-define vibronic structures with a predominance of the 0-0 transitions and an energy difference of 0.16 eV. The fluorescence lifetimes follow a monoexponential decay with a value s 5 630 6 30 ps. Atomic force microscopy, AFM, indicated a tendency of polyrotaxanes to organize into fibers. The advancing contact angles indicated higher surface hydrophobicity and lower surface free-energy values for polyrotaxanes compared with their unthreaded analogues. The device based on PFBTh•PSbCD:PCBM in a 1/1 w/w ratio under simulated AM 1.5G illumination at 100 mW cm 22 exhibited improved photovoltaic parameters of cells, resulted in high V oc (0.68 V), J sc (1.65 mA cm 22 ), FF (31.6%), and PCE (0.35) values, compared with PFBTh or PFBTh•PMebCD, respectively.

Synthesis, Photophysical, and Morphological Properties of Azomethine‐Persylilated α‐Cyclodextrin Main‐Chain Polyrotaxane

“…In addition, the nature of the interactions at the solid--liquid interface has also been investigated by using the Owens and Wendt approach. [ 29,43 ] The calculated total surface-free energy (γ S ) shows lower values for 3•TMS-αCD and 4•TMS-αCD samples (Table 3 ). One can also notice that both dispersive and polar components are lower and quite similar for the encapsulated surfaces than that of the reference 3 .…”

“…Taking into account, the decrease in the surface free energies of 3•TMS-αCD and 4•TMS-αCD , these results clearly denote the existence of a close packing hydrocarbon units on the surfaces. [ 29,44 ] …”

“…[ 16,17,19,21,22 ] The use of permodifi ed CDs derivatives, which exhibit higher solubility in nonpolar organic solvents and lower propensity to aggregate formations [ 23,24 ] has been employed as an alternative supramolecular approach for the synthesis of polyrotaxanes with conjugated polymers. [25][26][27][28][29][30] Recently, permethylated αCD has been shown to produce PAMs main-chain polyrotaxanes with better solubility in common organic solvents and easier processability with respect to the nonrotaxane ones. [ 31 ] As a continuation of our previous studies, we decided to explore the effect of hexakis(2,3,6-trimethylsilyl) α-cyclodextrin (TMS-αCD), as an alternative approach to bring some benefi ts on the photophysical characteristics of PAMs.…”

Фотовольтаический Эффект И Подвижность Носителей Заряда В Слоях Композиции Сополимера Битиофена Или Ротаксана На Его Основе И Производного Фуллерена C-=sub=-70-=/Sub=-

“…Нанизывание" макроцикла на со-пряженные цепи макромолекул не нарушает π-сопряжения вдоль цепи и способствует улучшению растворимости, морфологии, термической стабильности и пленкообразующей способности полученного комплек-са [5][6][7][8].…”

Calixarenes containing modified meso bridges

“…they form inclusion complexes useful in various fields, 1 form calixarene capsules, 2 are promising as chiral NMR solvating agents, 3 form gold 4 and silver 5 nanoparticles, are useful as catalysts 6 and as liquid crystals, 7 serve for design of sensors [8][9][10] and are promising as therapeutic agents. 11,12 Calixarenes belong to the family of cage macrocycles, including besides them cyclodextrins, [13][14][15] cucurbiturils 16,17 and pillararenes. 18 All macrocycles of this family are useful in the field of supramolecular chemistry for formation of inclusion complexes 1,[19][20][21] and rotaxanes in which they serve as rings.…”