Relatively effective polymer solar cells are built by thermal annealing of caesium carbonate. Caesium carbonate increases the energy effectiveness of the power conversion of solar cells and enhances the life times of the equipment. The studies done on UPS and XPS reveal that the system will do less work due to the thermal annealing of the  layer. Caesium carbonate breaks down into Caesium monoxide| and Caesium peroxide| by thermal evaporation. It was suggested that, when  combines with  they produce n-type dopes that supplies additional conducting electrons to the host devices. This produces a highly efficient inverted cell that can be used to further improve the efficiency of polymer solar cells or to design adequate multijunction photovoltaic cells.
The nanostructure layers of  can be used as cathodes for organic electronic materials due to its capacity to increase the kinetic energy of the electrons. The nanostructure layers of caesium carbonate had been probed for various fields using different techniques. The fields include such as photovoltaic studies, current-voltage measurements, UV photoelectron spectroscopy, X-ray photoelectron spectroscopy, and impedance spectroscopy. The n-type semiconductor produced by thermal evaporation of  reacts intensively with metals like Al, and Ca in the cathode. This reaction will cut down the work the cathode metals. Polymer solar cells based on solution process are under extensive studies due to their advantage in producing low cost solar cells. Lithium fluoride has been used to raise the power conversion efficiency of polymer solar cells. However, it requires high temperatures (> 500 degree), and high vacuum states raise the cost of production. The devices with  layers have produced equivalent power conversion efficiency compared with the devices that use lithium fluoride. Placing a  layer in between the cathode and the light-emitting polymer improves the efficiency of the white OLED.