Renewable energy is becoming popular. Solar radiations that reach the Earth are sufficient for global demand. Mono-lithic and tandem photovoltaic (PV) devices are used, with efficiencies above 15%, but demand costly special preparations. Mono-lithic photoelectrochemical (PEC) systems are easier to prepare, but still demand advanced techniques. Nano-film electrodes are more economic, easier to prepare and more environmentally friendly. To cultivate visible light, the major component of solar light, medium band gap (2.4 -1.8 eV; 550 – 700 nm) semiconductor electrodes are needed. Good candidates are metal-chalcogenides MX {M = Cu, Cd, Zn, etc., X = S, Se, Te and others}. Such nano-film electrodes showed low conversion efficiencies and low stabilities under PEC conditions. It thus is necessary to modify such materials. Different techniques enhanced conversion efficiency up to 8%. We target much higher efficiencies (more than 15%) and stabilities for nano-film electrodes that resemble PV systems. For this purpose a new facile modification technique has been developed here. The technique involves attaching thin composite material matrices (~80 nm) to the electrode surface. The composite involves stable electro-active materials, such as metalloporphyrine complexes, embedded inside stable polymer matrices such as polyethylene or polysiloxane. By this method, unprecedented high conversion efficiencies (~15% for CuSe films and ~18% for CuS films) have been obtained. Moreover, the modified electrodes were stable under PEC conditions. The composite materials affected the band edge positions of the semiconductor film electrodes. The metalloporphyrin complexes behaved as charge transfer catalysts across the solid liquid junction in the PEC system and prevented accumulation of positive holes in the space charge layer. As such, the film electrode was protected from photo-corrosion. Details of our results will be presented together with a model that explains the metalloporphyrin actions. Keywords: Nano-films, metalloporphyrin matrices, PEC conversion efficiency and stability

Conference Title

first International Symposium on Dielectric Materials and Applications (ISyDMA-2016)

Conference Country

Morocco

Conference Date

May 4, 2016 - May 6, 2016

Conference Sponsor

Sciences Faculty of Kenitra & Conference Centre of Mohammed VI Foundation/University Ibn Tofail

Additional Info

Conference Website