Nanostructured Semiconductor Materials for Dye-Sensitized Solar Cells

Abstract

Since O’Regan and Grätzel’s first report in 1991, dye-sensitized solar cells (DSSCs) appeared immediately as a promising low-cost photovoltaic technology. In fact, though being far less efficient than conventional silicon-based photovoltaics (being the maximum, lab scale prototype reported efficiency around 13%), the simple design of the device and the absence of the strict and expensive manufacturing processes needed for conventional photovoltaics make them attractive in small-power applications especially in low-light conditions, where they outperform their silicon counterparts. Nanomaterials are at the very heart of DSSC, as the success of its design is due to the use of nanostructures at both the anode and the cathode. In this review, we present the state of the art for bothn-type andp-type semiconductors used in the photoelectrodes of DSSCs, showing the evolution of the materials during the 25 years of history of this kind of devices. In the case ofp-type semiconductors, also some other energy conversion applications are touched upon.

Effect of Alkyl Chain Length on the Sensitizing Action of Substituted Non‐Symmetric Squaraines for p‐Type Dye‐Sensitized Solar Cells

“…The existence of such limits is indicated by the values of the diffusion length ( L h ), a microscopic parameter which showed a trend quite similar to the one of D h (Table ) with DS_47 still presenting the largest value of L h (4.36 μm, Table – in all the cases here examined it results L h > l =2.5 μm). A large number of mobile photoinjected charges generally implies a major difficulty in creating large concentration gradients with detrimental effect on the process of charge diffusion, i. e. the actual process originating the electrical current in nanostructured semiconducting electrodes . The relatively high diffusivity of charge carriers in DS_47 sensitized electrodes (Table ) is then indicative of a scarce concentration of charge carriers introduced in NiO after DS_47 excitation and the presence of a relatively large concentration gradient and a large diffusion length.…”

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

“…7 The porous semiconductor's physical and chemical properties largely depend on preparation conditions which, therefore, have an impact on the DSSC performance. 22 ZnO grown from electrochemical techniques shows promising properties and efficiencies can be achieved which are high among photoanodes prepared at low temperature. 6,7 In our recent work, we therefore employed the Co(bpy) 3 2+/3+ redox couple in DSSCs based on electrodeposited ZnO.…”

Caesium for Perovskite Solar Cells: An Overview

“…It is known that colloidal nanocrystals of CsPbI 3 (typically, in the 2–20 nm range) are more stable in the cubic phase at room temperature than in bulk CsPbI 3 , unlike polycrystalline thin films, in which the phase transition is expected to be similar as in the bulk . Moreover, the possibility to confine these perovskites at the nanoscale paves the way to synthesise band‐gap tuneable CsPbI 3 perovskites . Easily processed in solution (e.g., by means of simple spin‐coating), colloidal nanocrystals of inorganic lead halide perovskite could be dispersed into a variety of solvents and matrices and, eventually, incorporated into various device .…”