Improvement in the efficiency of silicon PV modules with a highly luminescent copper(I)-I-based coordination compound by using different processing strategies

This research shows how the copper(I) iodide coordination compound, [Cu4I6(pr-ted)2] (pr-ted = 1-propyl-1,4-diazobiciclo[2.2.2]octan-1-ium) can be an excellent downshifter to improve the efficiency of commercial multicrystalline silicon (mc-Si) photovoltaic (PV) modules. This compound was selected for its intense green emission, high photoluminescence quantum yield, high thermal stability, and single-step synthesis in water/ethanol at room temperature. Different types of configurations were investigated to integrate it into mc-Si PV modules. Thus, microcrystalline powder was deposited as a thin layer or as part of a composite film by means of its dispersion in commercial ethylene vinyl acetate (EVA). Both the transparency and concentration have been studied as critical factors that influence the resulting external quantum efficiency and the power conversion efficiency of the modified PV modules. The efficiency improvements are very relevant compared to previous examples based on lanthanides. Depending on the method used for the deposition on the PV module, different efficiency increases can be achieved reaching 0.36 and up to 0.42 percentage points with 0.05 and 0.1 mg/cm2 of compound. Since the composite film approach offers the possibility of industrial manufacturing of the modified EVA with the downshifter, the hot-pressing production of [Cu4I6(pr-ted)2]@EVA films was carried out on a large scale.