Silicon Nanocrystals and Semiconducting Single-Walled Carbon Nanotubes Applied to Photovoltaic Cells

We demonstrate the feasibility of bulk-heterojunction (BHJ) photovoltaic solar cells, which consist of surfactant-free silicon nanocrystals (size ∼3 nm) and semiconducting single-walled carbon nanotubes (diameter ∼1 nm) sandwiched between Al and ITO electrodes. In particular, we demonstrate that BHJ cells composed of p-type doped Si-ncs, in contrast with n-type, show a diode-like behavior, short-circuit current, and open-circuit voltage because the energy levels between p-type Si-ncs and semiconducting SWCNTs are adequate for exciton dissociation and carrier generation. Prototype BHJ cells made of p-type doped Si-ncs and semiconducting SWCNTs harvest sun light in broad spectral range 300–1400 nm.