A Study of Ca-Mg Silicate Crystalline Glazes——An Analysis on Forms of Crystals

In the study on Ca-Mg silicate crystalline glazes, we found some disequilibrated crystallization phenomena, such as non-crystallographic small angle forking and spheroidal growth, parasitism and wedging-form of crystals, dendritic growth, secondary nucleation, etc. Those phenomena possibly resulted from two factors: (1) partial temperature gradient, which is caused by heat asymmetry in the electrical resistance furnace, when crystals crystalize from silicate melt; (2) constitutional supercooling near the surface of crystals. The disparity of disequilibrated crystallization phenomena in different main crystalline phases causes various morphological features of the crystal aggregates. At the same time, disequilibrated crystallization causes great stress retained in the crystals, which results in cracks in glazes when the temperature drops. According to the results, the authors analyzed those phenomena and displayed correlative figures and data.

Controlling molecular weight of naphthalenediimide-based polymer acceptor P(NDI2OD-T2)for high performance all-polymer solar cells

A widely-used naphthalenediimide （NDI） based electron acceptor P（NDI2OD-T2） with different number- average molecular weight （Mn） of 38 （N2200L）, 56 （N2200M）, 102 （N2200H） kDa were successfully prepared. The effect of molecular-weight on the performance of all-polymer solar cells based on Poly（5-（5-（4,8- bis（ 5-decylthiophen-2-yl ）-6-methylbenzo[1,2-b： 4,5-b＇]dithophen-2-yl ）thiophen-2-yl ）-6,7-difluoro-8- （5-methylthiophen-2-yl）-2,S-bis（3-（octyloxy）phenyl）quinoxaline） （P2F-DE）：N2200 was systematically investigated. The results reveal that N2200 with increased M. show enhanced intermolecular interac- tions, resulting in improved light absorption and electron mobility. However, the strong aggregation trend of N2200H can cause unfavorable morphology for exciton dissociation and carrier transport. The blend film using N2200 with moderate M. actually develops more ideal phase segregation for efficient charge separation and transport, leading to balanced electron/hole mobility and less carrier recombi- nation. Consequently, all-polymer solar cells employing P2F-DE as the electron donor and N2200M as the electron acceptor show the highest efficiency of 4.81%, outperforming those using N2200L （3,07~;） and N2200H （S,92%）. Thus, the Mn of the polymer acceptor plays an important role in all-polymer solar ceils, which allows it to be an effective parameter for the adjustment of the device morphology and efficiency.