NanoCuI · Nano-Copper Iodide: A New Material for High Performance P-Type Dye-Sensitized Solar Cells

Nano-Copper Iodide: A New Material for High Performance P-Type Dye-Sensitized Solar Cells

The problem we chose to address in NanoCuI was the very weak performance of p-type dye sensitized cells (p-DSSCs), a new type of solar energy device. p-DSSCs promise to increase the efficiency of dye-sensitized solar cells (DSSCs) by enabling tandem cells that absorb light at both electrodes, and lead to a new generation of efficient low-cost photovoltaics. However, no component of the p-DSSC is fully optimised, to the extent that tandem DSSCs are currently less efficient than conventional DSSCs based on a photoanode alone. The major bottleneck in the p-DSSC appears to be nickel oxide (NiO) substrates used as the semiconductor, due their inefficient charge transport. In NanoCuI we investigated the synthesis of new copper(I) iodide electrodes which in theory, should be capable of transporting charge much better, and could form a basis for new, efficient p-DSSCs. This work is important for society because it could contribute to development of clean, low-cost energy sources. Moreover, CuI has other potential uses in electronics and photonics that make development of nanoporous CuI electrodes, our goal, important. Nanoporosity is essential to provide the high surface area for dye binding, that gives high light absorption and efficient photosensitisation. The overall objectives were: 1. Develop routes to nanoporous CuI (np-CuI) electrodes supported on conductive glasses 2. Characterize the np-CuI materials 3. Synthesize sensitizers for np-CuI 4. Assemble and test np-CuI based p-DSSCs The overall conclusions are: 1) Nanoporous CuI can be produced by a very simple, chemical method but our characterisation has indicated that it is not the required, gamma form of the material. Instead, we appear to form an unusual, metastable high temperature form of the material known as CuI-IV. Previously, this has only been observed at ca. 670 K during the transition between the gamma and beta forms. Formation at room temperature is thus remarkable, though not yet understood. 2) Electrodeposition produced nano-sized gamma-CuI particles, however the resulting materials are not porous. 3) Pyridines seem to be the best binding groups for dyes on CuI. 4) Films of CuI-IV are not conductive enough to work well in p-DSSCs, while our gamma-CuI films are not porous enough. Thus, so far, we have been unable to produce CuI-based p-DSSCs that perform as well as existing devices based on NiO.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз