Luminescent Downshifting Layers Using Organic Dyes and Quantum Dots

The use of an analytical model on luminescent downshifting layers (LDSLs) has been used to estimate the short‐circuit current. Various LDSL have been tested with two different polymers and luminescent materials. These devices have been coupled with a CIGS solar cell. The CdSe/ZnS quantum dots (QD) and Lumogen organic dyes are added in a polymeric scaffold to do a luminescent waveguide increasing the absorption in the UV range. The experimental short‐circuit current are compared to the calculated short‐circuit current. In this model, only the effects of the dyes were taken into account. It has been demonstrated a good correlation between the experimental and the theoretical values. Moreover, different coupling architectures have been experimented. The impact of the interface between LDSL and the solar device is not negligible. It has been experimentally proved the interface change can improve about 40–80% with an ethanol interface. The increase can reach 60–90% with a glycerine interface. The change of this interface impacts directly on the scattering effects and decrease the losses due to the surface defects.

A luminescent downshifting layer (LDSL) is made of a polymeric matrix containing fluorescent materials. Lumogen (BASF) organic dyes and CdSe/ZnS quantum dots are the two materials studied for their downshifting properties. These LDSLs coupled with a solar cell permit to enhance their electrical properties. An analytical model is used to understand the behaviour of the LDSLs coupled with a CIGS solar cell.