Cesium phase change

Cesium, Cs, and rubidium, Rb, form ideal solutions in the liquid phase, and regular solutions in the solid phase. Their standard state Gibbs free energy changes of melting as a function of temperature, AG c. = (G°cs.l 0,5) and = (G° - G°, 5) respectively, are... 

Lelieur. J. P- Lcpoulre. G. Imm- Chan. 1988. 27. 1883-1890 1989. 28. 195-200 1 Cesium appears to be an exception. Although the solution changes from blue lo bronze with increasing concemratkjn. a two-phase system is never obtained. 

Fig. 5. Phase separation temperature changes of the aqueous solutions of PNIPAM containing pendant 11.6 mol % crown ether groups by the addition of potassium chloride (O), sodium chloride (3), lithium chloride (C), and cesium chloride ( ). Polymer concentration was 1 mass %...

Cesium appears to be an exception. Although the solution changes from blue to bronze with increasing concentration, a two-phase system is never obtained. 

The two-phase titration can be also successfully used for the determination of cationic surfactants using standardized solutions of anionic surfactants. In this case the mechanism of titration is the reverse, i.e. the chloroform layer undergoes color change from blue to pink. More often, and especially at higher concentrations, cationic surfactants are determined by two-phase titration using sodium tetraphenylborate titrant and bromophenol blue indicator [32], Tetraphenylborate ion is also used in the determination of potassium, rubidium and cesium, so the ions of these metals, if present, interfere with the determination of quaternary ammonium surfactants by this method. 

Here we show that the polarity of polymer solar cells can be reversed by changing the position of two interfacial layers vanadium oxide (V2O5) layer as hole injection and cesium carbonate (CS2CO3) layer as electron injection, independent of the top and bottom electrodes. ° Since our first demonstration of inverted solar cells, more and more interests have focused on this new architecture. Waldauf et al. demonstrated inverted solar cells with a solution-processed titanium oxide interfacial layer. White et al. developed a solution-processed zinc oxide interlayer as efficient electron extraction contact and achieved 2.58% PCE with silver as a hole-collecting back contact. It is noteworthy to mention that EQE value for inverted solar cells approaches 85% between 500 and 550 nm, which is higher than that of normal polymer solar cells. This is possibly due to (i) the positive effect of vertical phase separation of active layer to increase the selection of electrode and (ii) lower series resistance without the PEDOT PSS layer. 

---