Controllable Design And Application Of New Counter Electrodes For Dye-sensitized Solar Cells

Dye-sensitized solar cells (DSCs) have been recognized as a promising candidate for the next-generation photovoltaic devices due to their low manufacturing cost and high power conversion efficiency in contrast with conventional silicon solar cells. They have been attracting much attention since Gratzel and co-workers developed it in1991. In a DSCs system, CE plays a crucial role as it collects the electrons flowing from the external circuit and catalyzes the reduction of I3-to I-, realizing the regeneration of the sensitizer. Platinum (Pt) has been a cornerstone material for CE because of its superior electrocatalytic activity, high electrical conductivity and good stability. Considering that simple, low-cost fabrication processes are of pivotal interest for the commercialization of DSCs, much effort has been made to either replace Pt with cost-effective alternative materials or develop easy methods to obtain Pt CE with high catalytic activity. In this work, we prepared a continuous nanostructured Pt-mirror film with metallic lustre and good adhesion to the F-doped tin oxide conducting glass (FTO) substrate, further investigated the electrochemical catalytic performance of the Pt-Mirror electrode. The interstitial N-In2O3nanocrystals was synthesized by a wet chemical technique, and the catalytic activity of N-In2O3towards I3-reduction was also investigated. The main conclusions are listed as following:(1) The mirror-like Pt film could be facilely deposited on the FTO substrates at low temperature by in situ growth method. The film deposited by this method had dense structures and good adhesion to the FTO due to the Pt nanoparticles grown from the substrate. Pt-M CE shows impressive improvement of catalytic activity for I3-reduction, with a high energy conversion efficiency of7.49%in the DSCs systems. Compared with conventional Pt-CE, the enhancement of the energy conversion efficiency and the short-circuit current density (Jsc=18.50mA cm-2) are18.5%and15.3%, respectively.(2) A trace amounts of interstitial N atoms was introduced to In2O3nanocrystals via decompostition of the indium nitrate, which serves as both reactant and dopant source. The energy conversion efficiency of the DSCs with N-In2O3CE was7.78%, while CE was just0.96%. The N-In2O3CE exhibited better catalytic activity toward I3-reduction reaction than In2O3CE, and it has been proved by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Tafel.