Improving spectral response of monocrystalline silicon photovoltaic modules using high efficient luminescent down-shifting Eu3+ complexes

One way to improve the spectral response of solar cells in the ultraviolet (UV) region is to convert high energy photons into lower energy ones via luminescent down-shifting (LDS) technique. Eu3+ complexes are excellent LDS species because of their high luminescence quantum efficiency and large Stokes-shift. In this paper, we aim to optimize the LDS property of Eu3+ complexes for monocrystalline silicon (c-Si) photovoltaic (PV) modules by chemical modification of the UV absorbing antenna ligands. Our results show that the LDS performances of Eu3+ complexes are strongly dependent on their absorption and emission properties. By carefully modifying the absorption and emission features, the LDS performances of Eu3+ complexes can be significantly improved. The spectroscopic features of the Eu3+ complex with a bispinene-containing bipyridyl ligand match well with the requirement of ideal LDS species for the c-Si PV module. Simple coating of polyvinyl acetate film doped with this complex onto the surface of c-Si PV module leads to increase of the external quantum efficiency in the UV region and enhancement of the PV module efficiency (from 16.05% to 16.37%). Copyright (c) 2012 John Wiley & Sons, Ltd.