Broad Spectral Response Using Carbon Nanotube/Organic Semiconductor/C₆₀ Photodetectors

We demonstrate that photogenerated excitons in semiconducting carbon nanotubes (CNTs) can be efficiently dissociated by forming a planar heterojunction between CNTs wrapped in semiconducting polymers and the electron acceptor, C(60). Illumination of the CNTs at their near-infrared optical band gap results in the generation of a short-circuit photocurrent with peak external and internal quantum efficiencies of 2.3% and 44%, respectively. Using soft CNT-hybrid materials systems combining semiconducting small molecules and polymers, we have fabricated broad-band photodetectors with a specific detectivity >10(10) cm Hz(1/2) W(1-) from lambda = 400 to 1450 nm and a response time of tau = 7.2 +/- 0.2 ns.