Enhancing the Efficiency of Production CdS/CdTe PV Modules by Overcoming Poor Spectral Response at Short Wavelengths Via Luminescence Down-Shifting

Many commercially-produced photovoltaic (PV) modules exhibit poor external quantum efficiency (EQE) at short wavelengths (lambda). However, the addition of a luminescent down-shifting (LDS) layer can absorb these short lambda photons that would not have contributed towards electron-hole pair generation in the solar cell, and re-emit them at longer lambda where the PV device possesses a much higher IQE. The LDS is performed via a mixture of up to four fluorescent organic dyes, which are cheap, photostable, and exhibit near-unity luminescence quantum efficiencies (LQE). Ray-tracing simulations in this paper demonstrate that an LDS layer containing three dyes can significantly enhance the short-circuit current density (J_sc) of cadmium sulphide/cadmium telluride (CdS/CdTe) solar cells by DeltaJ_sc =3.1 mA/cm², corresponding to an increase in conversion efficiency (eta) from eta=9.6% to eta=11.2% under air-mass 1.5 global (AM1.5g) solar radiation. Significantly, the application of LDS layers does not require any alteration to the structure of the solar cell