| In this paper,we control the molecular-level motions of a multi-component supramolecular crystal are amplified into macroscopic changes of crystals by co-assembly of Bpe and TCNB(1,2,4,5-tetracyanobenzene)into a charge-transfer complex.The as-prepared cocrystals show remarkable stacking behavior and modifying the self-assembling processes during intermolecular forces phase transitions compared with different proportions of one-component organic single crystals,organic cocrystals with unique packing structures and aggregate states show a variety of novel optoelectronic properties through multi-component synergistic and collective effects,paving the way to the development of high-performance or multifunctional optoelectronic devices.Moreover,the charge transfer pathway between donor(D)and acceptor(A)in organic cocrystal is also fundamentally interesting.In addition,the analysis of time dependent charge transfer process provides more information to further understand the crystallization dynamics.Therefore,revealing the nucleation and growth mechanism of organic charge transfercrystals and modifying the self-assembling processes will drive the development of a new class of organic nano electronics.(1)Typical 1,2,4,5-tetracyanobenzene(TCNB and trans-1,2-bis(4-pyridyl)ethylene(4,4BPE)was synthesized TCNB:Bpe cocrystals proportionally by self-assembly driving force.Different luminescent properties were observed by the test result of all sample photoluminescence spectra(PL).The crystallinity of the cocrystal was found to decrease with the increase of TCNB content in the cocrystals composition.The PL spectrum peak of TCNB:Bpe was 412nm,compared with TCNB and Bpe crystals,and the cocrystals of PL spectrum was significantly wider.The TCNB:Bpe cocrystals material was kept at a saturated dichlorobenzene vapor atmosphere by the evaporation method of thermal saturation solution,to change the proportion of TCNB with gradient increasing in the synthesis process(0%;25%;50%;75%;100%).After the solutions was mixed with different proportions,crystalline forms of molecules where alternatives to polymorphs.The results show that:The intermolecular forces of TCNB can give cocrystals synthetic process sufficient time and driving force to develop into the nucleus.It can alter crystal shapes relative to pure energetic components involved,the resulting shapes of cocrystal can range from a few microns to a few hundred micrometers.Polymorphs offer a unique opportunity to study the structure-property relationships of the same compound formed in different supramolecular components.It is proved that the concentration of TCNB in the controllable blend solution can optimize the morphology of the crystal.(2)We observed the stacking modes between poly(3-thiophene)and fullerene are mainly segregated-stacking and mixed-arrangement within crystals.Based on real-time structure analyses,poly(3-thiophene)and fullerene do not show crystallization initially in the solution state although there exists antisolvent.However,poly(3-thiophene)completed crystallization and demonstrated ordered nano wire structures after 90 min evolution,while,fullerene needs long time saturated evaporation to crystallize.In addition,the analysis of time dependent charge transfer process provides more information to further understand the crystallization dynamics.The charge transfer between P3HT and C60 is quantified by ESR measurement.Wide Angle X-ray scattering(WAXS)spectra proved that the P3HT matrix blend C60 fullerene would reduce the peak strength and ?-? interband transition of P3HT blueshift and the absorption coefficient was decreased.further research to unpaired charge and spin state of donor-acceptor crystals about time curve of special features with electron spin resonance(ESR),this work reveals the organic crystal nucleation growth mechanism of the charge transfer and through the modified self-assembly process to promote the development of a new generation of organic nano electronic devices,to master the synthesis of the crystal growth mechanism. |
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