Imaging-based beam steering for free-space optical communication.

Imaging-based beam steering (IBBS) provides a route to compact, low-power, and low-cost beam steering ideal for mobile free-space optical communications (FSOC), LIDAR imaging, and other active illumination applications. In IBBS, a lens passively maps each pixel of a 2D emitter array into a unique line-of-sight direction. Electronic beam steering of multiple beams with dynamic beam shaping is implemented via pixel selection.

Independent control of bulk and interfacial morphologies of small molecular weight organic heterojunction solar cells.

We demonstrate that solvent vapor annealing of small molecular weight organic heterojunctions can be used to independently control the interface and bulk thin-film morphologies, thereby modifying charge transport and exciton dissociation in these structures. As an example, we anneal diphenyl-functionalized squaraine (DPSQ)/C(60) heterojunctions before or after the deposition of C(60). Solvent vapor annealing of DPSQ before C(60) deposition results in molecular order at the heterointerface.

Small-molecule photovoltaics based on functionalized squaraine donor blends.

Two squaraine (SQ) donor molecules with different absorption bands are blended together for better coverage of the solar spectrum. The blend SQ device shows a significant improvement compared with single SQ donor devices. By applying a solvent annealing process and a compound buffer layer, a power-conversion efficiency of 5.

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.