Impact of Solubility of Organic Semiconductors for Solution-Processable Electronics on the Structure Formation: a Real-Time Study of Morphology and Electrical Propertiesстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus
Аннотация:Control of structure formation in the active layers of organic solar cells allows improving their processability and enhancing the efficiency of the final devices. In the present work, in-situ studies of film formation from binary toluene solutions of an electron donor, poly(3-hexylthiophene (P3HT), and an electron acceptor such as [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) or indene-C60 bisadduct (ICBA) have been conducted. The experiments were carried out by GIWAXS with simultaneous electric current measurements. The comparative analysis of intensity of the amorphous halo, 100 and 020 peaks of P3HT reveals the development of the semicrystalline morphology of the donor through a partly ordered phase. The experiments show the impact of the chemical structure of the acceptor and that of the donor:acceptor ratio on the kinetics of drying and crystallization. The optimal bulk heterojunction morphology was achieved for P3HT:ICBA 1:1, which was exhibiting the highest value of current. A more efficient phase separation in non-annealed P3HT:ICBA films as compared to P3HT:PCBM was accounted for by the differences in solubilities of the components in toluene. The structure formation during solvent evaporation can be subdivided in three stages including ordering of polymer in solution, phase separation during precipitation and perfectioning of P3HT crystals in the dry film.