Broadband energy harvesting with nano-composite PbS-Nanocrystal/Excimer laser crystallized thin film silicon hybrid solar cells

Photovoltaics between hydrogenated amorphous silicon (a-Si:H) and PbS-nanocrystals (NCs) are demonstrated. Enhanced spectral response was observed below 375 and beyond 800 nm for a-Si:H/PbS-NCs compared to a-Si:H devices using external quantum efficiency measurements (EQE). Further improvement of EQE was observed from hybrid devices fabricated using a-Si:H subjected to excimer laser crystallization (ELC). This improvement is attributed to the reduction in the a-Si:H band gap through ELC, resulting in a lower barrier for hole extraction from the PbS-NCs. Techniques discussed in this paper would be useful for the fabrication of highly efficient a-Si:H and nanocrystal based hybrid photovoltaics in future.