Developing Flexible Quinacridone-Derivatives-Based Photothermal Evaporaters for Solar Steam and Thermoelectric Power Generation

Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air−water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN−4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN−4CQA@Paper combines desired chemical and physical properties, broadband light-absorbing, and shape-conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar-steam and solar-electricity technologies by integrating DCN−4CQA@Paper and the thermoelectric devices is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas.     

Localizing Binding Sites on Bioconjugated Hydrogen-Bonded Organic Semiconductors at the Nanoscale

Hydrogen-bonded organic semiconductors are extraordinarily stable organic solids forming stable, large crystallites with the ability to preserve favorable electrical properties upon bioconjugation. Lately, tremendous efforts have been made to use these bioconjugated semiconductors as platforms for stable multifunctional bioelectronics devices, yet the detailed characterization of bio-active binding sites (orientation, density, etc.) at the nanoscale has not been achieved yet. The presented work investigates the bioconjugation of epindolidione and quinacridone, two representative semiconductors, with respect to their exposed amine-functionalities. Relying on the biotin-avidin lock-and-key system and applying the atomic force microscopy (AFM) derivative topography and recognition (TREC) imaging, we used activated biotin to flag crystal-faces with exposed amine functional groups. Contrary to previous studies, biotin bonds were found to be stable towards removal by autolysis. The resolution strength and clear recognition capability makes TREC-AFM a valuable tool in the investigation of bio-conjugated, hydrogen-bonded semiconductors.     

The effect of pigments on the crystallization and properties of polypropylene

The effect of pigments of different chemical compositions on the crystellization process of PP was studied by means of differential scanning calorimetry in isothermal mode. The Avrami equation was applied to obtain the crystallization parameters of polypropylene with different pigments. Lipatov's equations were applied for evaluation of the thickness and volume content of the transition layers. Results show that pigments affect not only the degree of crystallinity but also the structure of the amorphous phase and the integrity of the crystalline/amorphous interphase. Finally, the morphology and mechanical properties of pigmented polypropylene were studied in view of the different chemical compositions of the various pigments.     

Synthesis of Soluble Quinacridone Photocatalysts for the Homogeneous Oxidation of Thioethers

Evaluation of quinacridone (QA) derivatives as homogeneous metal-free photocatalysts is here presented. QA derivatives were synthetized and systematically characterized, measuring their ground state and excited state redox potentials in dichloromethane (DCM) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), in order to understand how structural modifications influenced their photocatalytic properties. In particular, the effect of dicyanomethylene and nitro EWG groups was investigated, in order to develop a photocatalyst capable of promoting oxidative processes in the presence of molecular oxygen. Among the analyzed derivatives, 2,9-dinitro-N,N′-dibutylquinacridone (DNDBQA) was the one with the highest excited state reduction potential (E_red*=1.60 V in HFIP vs SCE), while N,N’-dibutylquinacridone (DBQA) showed valuable excited state redox potentials (E_red*=1.29 V; E_ox*=−1.28 V in HFIP vs SCE), making it suitable for bimodal applications in oxidative and reductive photocatalytic processes. Afterwards, the synthetized QA derivatives were examined as photocatalysts to promote the selective aerobic oxidation of thioether to sulfoxide. Promising results in thioanisole oxidation were achieved with all the QA derivatives tested as photocatalysts, in terms of yield and selectivity. Remarkably, DBQA showed the best performances, catalyzing the reaction in only 20 minutes, using 0.5 % of the photocatalyst, and showing excellent performances in the oxidation of several thioether derivatives.     

Ultrasound responsive organogels based on cholesterol-appended quinacridone derivatives with mechanochromic behaviors

A series of cholesterol-appended quinacridone (QA) derivatives 1a-1d have been synthesized,in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation.Field emission scanning electronic microscope (FESEM) and transmission electron microscopy (TEM) of xerogels or precipitates indicated that 1b and 1c formed 1D fibrous nanostructure,while 1a assembled into 3D flower-like microstructures.The ultrasound-induced organogel process was characterized by kinetic UV...     

喹吖啶酮光物理性质的理论表征

运用密度泛函理论对喹吖啶酮的光物理性质进行了研究. 结果表明, B3LYP/6-31G(d)//TD-B3LYP-PCM/6-311＋G(d)和CIS/6-31G(d)//TD-B3LYP-PCM/6-311＋G(d)方法能分别较好地描述喹吖啶酮的光吸收和光发射性质. 在吸收和发射的电子跃迁过程中, 主要是π-π*跃迁, 电荷在N和O之间的转移, 既包括单分子内的电荷跃迁, 也包括了通过氢键或π-π作用形成的二聚体的电荷跃迁. 溶剂对其光物理性质是有影响的, 这种影响是通过改变其前线轨道能来实现的, 受影响最大的是最高占据分子轨道(HOMO).     

两种烷基取代喹吖啶酮衍生物LB膜的荧光特性

制备了两种烷基取代喹吖啶酮衍生物C6DHQA和C16DMQA的X型Langmuir-Blodgett(LB)膜,采用紫外-可见吸收、稳态荧光和时间分辨荧光的方法研究其溶液及LB的光学特性。研究结果表明,C16DMQA比C6DHQA的吸收谱整体红移,说明烷基链加长减小了分子的能级间隔;两者LB膜的吸收谱较溶液整体红移,说明在LB膜中形成了"J-聚集体"。两种材料的溶液及LB膜都有较强的荧光发射,溶液的荧光谱与吸收谱有很好的镜像对称关系,形成LB膜后,镜像对称关系被打破,两者第三个荧光峰相对强度差别很大。C6DHQA溶液中的荧光寿命为21ns左右,C16DMQA溶液中的荧光寿命为22ns左右,形成LB膜后,荧光寿命明显较少,两者第三个荧光峰对应的荧光寿命差别较大。其原因应归于C16DMQA分子在基板上的排列更密,分子间的相互作用力强,从而对能级结构的影响更大。     

Dimeric quinacridone cyclophanes: Synthesis,structures,and photophysical properties

Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demonstrated.These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions.A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for...     

通过不同烷基链取代调控喹吖啶酮分子在Ag(110)表面上的自组织结构

采用低能电子衍射、扫描隧道显微镜、第一性原理密度泛函理论计算以及分子力学计算，分别对不同烷基链取代的喹吖啶酮（QA）分子在Ag（110）基底上的吸附和生长进行了研究．QA和Ag基底的相互作用主要来自分子中0原子和Ag基底的共价键，它决定了分子的取向和最优吸附位置；而烷基链决定了分子吸附层的取向，QA分子间的排列可以通过烷基链的长度来调节．由此借助调节烷基链的长度，能够可控地制备具有不同物理性质的单层分子薄膜．