Despite their high efficiency in photovoltaic (PV) processes, semiconductor p-n junctions of a few mm thickness, demand special preparation conditions of ultra-high vacuum and high starting materials amounts which makes them environmentally unfriendly.  Currently, semiconductor polycrystalline thin film electrodes, of the order 100-500 nm thickness, are emerging as replacement for p-n junctions, in photoelectrochemical (PEC) processes. Nano-film electrodes demand little starting materials with low cost preparation methods, such as chemical bath deposition (CBD) or electrochemical deposition (ECD).  This also makes them more environmentally friendly. However, thin film electrodes, especially those of metal chalcogenides, are known to be unstable to photodegradation with low conversion efficiency. Therefore, modification of nano-film electrodes is imperative. In our efforts to prepare nano-film metal chalcogenide (MX, where M is Cd, Cu, Pb, etc; and X is O, S, Se or Te) with high stability and conversion efficiency at SSERL-ANU, we have followed four simple strategies. Firstly, we used combination of ECD and CBD to prepare more compact films with sound thickness. Secondly, we carefully controlled the annealing temperatures that suit the values of the semiconductor band gap values. Thirdly, we controlled the cooling rates of the pre-annealed films in such away to suit the band gap values. Fourthly, we improved the charge transfer dynamics at the solid liquid junctions by introducing charge transfer catalysts at the surface. By combining these four strategies we have been able to reach highly stable metal chalcogenide nano-film electrodes with high conversion efficiency values up to 18%, far higher than expected by the US-DOE anticipations. Results, discussions and models will be rigorously presented in our talk, together with future application prospects.

Conference Title

Palestinian Conference on Modern Trends in Mathematics and Physics VII (2022)

Conference Country

Palestine

Conference Date

July 30, 2022 - Aug. 1, 2022

Conference Sponsor

Birzeit University/

Additional Info

Conference Website