Cu(I)-I coordination polymers as possible substitutes of lanthanides as downshifters for increasing the conversion efficiency of solar cells.

This work tries to contribute new solutions to increase the efficiency in the conversion of photons of the solar cells, by means of the use of photoluminescent Cu(I) coordination polymers (CPs), as possible alternative materials of lower cost, than those used in today, based on lanthanides. The selected CP of chemical formula [CuI(NH2MeIN)]n (NH2MeIN= methyl, 2-amino isonicotinate), absorbs in the utraviolet and emits in the visible, being also easily nanoprocessable, by a simple and one pot botom-up approach. Nanofibers of this CP, can be embedded in organic matrices such as Ethyl Vinyl Acetate (EVA), forming transparent and homogenous films, with thermal stability up to approximately 150oC. These new materials maintain the optical properties of the CP used as a dopant, ([CuI(NH2MeIN)]n), with emission in yellow (570nm) at 300K, which is intensified when the working temperature is lowered. Additionally, these materials can be prepared with varying thicknesses; from a few microns to a few hundred nanometers, depending on the deposition method used (drop casting or spin coating respectively). The study of their external quantum efficiency (EQE) shows an increase in the UV range, which translates into an increase in conversion efficiency. Being the optimal CP concentration of 5% by weight in order to do not to diminish the transparency of the composite material. The calculated cost on the possible incorporation of this material to solar cells, show a 50% decrease over the cost reported in similar studies based on the use of lanthanides