ORAL

SESSION: AdvancedMaterialsMonAM-R7	Marquis International Symposium on New and Advanced Materials and Technologies for Energy, Environment and Sustainable Development(3rd Intl Symp. on New and Advanced Materials and Technologies for Energy, Environment and Sustainable Development)
Mon Oct, 23 2017	Room: Condesa IB
Session Chairs: Toshinori Okura; Carlos Enrique Schvezov; Session Monitor: TBA

12:00: [AdvancedMaterialsMonAM03]
Nano-Structured Chalcogenide Materials for Economic and Efficient Solar Energy Converters
Yurii Vorobiov¹ ; Iker Rodrigo Chavez Urbiola² ; Rafael Ramirez Bon² ; Pavel Vorobiev³ ; Francisco Javier F. J. Willars Rodriguez² ; Paul Horley³ ; ¹CINVESTAV Unidad Queretaro, Queretaro, Mexico; ²CINVESTAV-IPN, Unidad Queretaro, Queretaro, Mexico; ³CIMAV Monterrey, Monterrey, Mexico;
Paper Id: 34 [Abstract]

Solar energy converters based on CdS/CdTe bilayer occupy a solid position in the market of renewable energy devices (the second most abundant photovoltaic technology). The other chalcogenide semiconductors, like CdSe, PbS, PbSe and PbTe are also of great interest for solar cell applications (in some of them the multi exciton generation was observed, the other can be part of efficient multi-layered converters). These materials are not expensive contrary to III-V semiconductors normally used in multi-layered cells, and can be produced by economic and ecologically friendly techniques like CBD (Chemical Bath Deposition) and its recent versions (SILAR - Successive Ionic Layer Adsorption and Reaction, and PCBD - Photo Chemical Bath Deposition). Our purpose was to study the effects of nano-porosity that is an essential feature of these methods; the corresponding quantum confinement affects the band gap value that can be used for its monitoring thus optimizing the device efficiency. The corresponding band gap variation can be regulated by experimental conditions; for illustration, in PbS we observed the band gap variation between 0.4 and 0.8 eV. Our experimental solar cell with CdS/PbS absorbing part has the external quantum efficiency of 25 %. We also found that in Glass/ITO/CdS/CdTe/Metal solar cell nano-structurization leads to formation of two-dimensional quantum wells near interfaces ITO/CdS and CdS/CdTe causing the blue shift of electronic transitions. Analysis of the structure made by XPS and Photoluminescence has shown that the CdS/CdTe active bilayer has several potential barriers that are responsible for the photo voltage generated by illumination. In general, we conclude that the quantum confinement effects caused by nano-structurization of semiconductor films for solar energy converters improve the converters' parameters.