Self-Passivating hybrid (organic/inorganic) tandem solar cell

A tandem photovoltaic device structure, consisting of a PbSe nanocrystal film and a P3HT/PCBM bulk heterojunction film, was fabricated. The PbSe film (top layer) serves as a photocurrent generator as well as a UV protector for the underlying polymer cell. The P3HT/PCBM photovoltaic cell (bottom layer) provides the necessary electric field to the top photoconducting layer to extract the photogenerated charge from that layer. The charge extraction from the PbSe layer is demonstrated by using light-biased spectral response measurements. In addition, device lifetime measurements were performed under AM 1.5 and UV-enhanced illumination on the tandem cell and on a control P3HT/PCBM device. These measurements demonstrated that the hybrid tandem cell is significantly more durable due to the preferential UV absorption in the upper inorganic PbSe nanocrystal film.