芳香酯类富勒烯衍生物的制备及光电性能研究

以PCBM为初始原料,经过水解、酯化反应,生成3类富勒烯衍生物,采用红外光谱(FT-IR)、核磁共振(1H NMR和13C NMR)、元素分析仪、质谱(MS)对产物结构进行了表征;并通过紫外可见光谱、循环伏安法等手段研究了目标物的光学与电化学性能,结果表明,目标物PCBTE、PCBBE、PCB(4-MOB)M的LUMO能级分别为-3.91 V、-3.88 V、-3.94 V。

On the synthesis and photovoltaic performance of the derivatives from aromatic esters fullerene

In this paper,the authors would like to report their work on modifying the molecular structure of PCBM in hoping to enhance the LUMO (the lowest unoccupied molecular orbital) energy level and heighten the open circuit voltage (Voc) as well as to further ameliorate the performance of PSCs with 6,6]-phenyl-C61-butyric acid methyl ester (PCBM).For the aforementioned purposes,the first step has to be the synthesis of PCBA.PCBM by adding toluene,acetic acid and hydrochloric acid to it.And,then,it is necessary to heat the mixture to be reacted together and then let them reflux for 28 h.Cooling the said mixture to the room temperature,water layer can be separated from by using a separating funnel,with the solvent having been removed under the reduced pressure and the product of PCBA collected through centrifugation.And,next,the second step is to synthesize chloride,for which a solution of PCBA in the carbon disulfide has to be added with sulfurous oxychloride and DMF.In proceeding with the said process,it is necessary to stir up the reaction mixture for 24 h at the temperature of 60 ℃,with the result of letting it cool to the room temperature.Last of all,the synthesis can be well turned into the target molecules.And,now,after the solvent is evaporated,the remaining product can be dissolved into carbon disulfide,with the mixture of different alcohols,carbon disulfide,and DMF added to the above solution.All the above procedures done,the solvent can be removed under the reduced pressure,whereas the mixture can be separated through silica gel chromatography with toluene to obtain PCBTE,PCBBE,PCB (4-MOB) M.The structures of the compounds we have gained can be characterized by means of FT-IR,1H NMR,13C NMR,MS and the elemental analysis approach.Furthermore,we have also made exploration of the optical properties of the fullerene derivatives by way of UV-Vis absorption spectroscopy.As the final result,the absorption spectra of derivatives prove to be almost totally similar to that of PCBM,which can be observed in a range between the sharp peak at 433 nm and the weak peak at 696 nm under the visible absorbance spectrum of PCBM analogs.Moreover,the electrochemical properties of the molecules can be evaluated through the cyclic voltammetry whereas the LUMO levels of PCBTE,PCBBE and PCB(4-MOB)M has to be made equal to-3.91 V,-3.88 V,-3.94 V,as shown in the results of calculation,correspondingly.Hence,the results we have gained demonstrate that PCBBE,with a higher LUMO energy level as the acceptor in PSCs,can help to raise the open circuit voltage (Voc),and in turn enhance the performance of PSCs.