Film Flip and Transfer Process to Enhance Light Harvesting in Ultrathin Absorber Films on Specular Back-Reflectors.

Optical interference is used to enhance light-matter interaction and harvest broadband light in ultrathin semiconductor absorber films on specular back-reflectors. However, the high-temperature processing in oxygen atmosphere required for oxide absorbers often degrades metallic back-reflectors and their specular reflectance. In order to overcome this problem, a newly developed film flip and transfer process is presented that enables high-temperature processing without degradation of the metallic back-reflector and without the need of passivation interlayers.

Phase formation and stability of Ag-60 at%Cu alloy nanoparticles synthesized by chemical routes in aqueous media.

The present work reports the nature of the evolution of an array of nanoparticles during the synthesis of alloy nanoparticles of Ag-60 at%Cu by the co-reduction of metal salt precursors using NaBH in an aqueous medium. This was achieved by studying samples extracted at different intervals of time from the reaction bath. The microstructural characterization reveals that at the initial stage of synthesis, a single-phase solid solution of alloy nanoparticles of very small sizes was formed; however, as the reaction time increases, a network of chains of nanoparticles evolves containing particles rich in either Ag or Cu.