Carrier multiplication, the generation of multiple electron-hole pairs by a single photon, is of great interest for solar cells as it may enhance their photocurrent. This process has been shown to occur efficiently in colloidal quantum dots, however, harvesting of the generated multiple charges has proved difficult. Here we show that by tuning the charge-carrier mobility in quantum-dot films, c...

Infrared (IR) light sources with high modulation rates are critical components for on-chip optical communications. Lead-based colloidal quantum dots are promising nonepitaxial materials for use in IR light-emitting diodes, but their slow photoluminescence lifetime is a serious limitation. Here we demonstrate coupling of PbS quantum dots to colloidal plasmonic nanoantennas based on film-coupled ...

Nitrogen doping has been a powerful way to modify the properties of carbon materials ranging from activated carbon to graphene. Here we report on a solution chemistry approach to nitrogen-doped colloidal graphene quantum dots with well-defined structures. N-doping was demonstrated to significantly affect the properties of the quantum dots, including the emergence of size-dependent electrocataly...

Silicon nitride waveguides with a monolayer of colloidal quantum dots embedded inside were fabricated using a low-temperature deposition process and an optimized dry etching step for the composite layers. We experimentally demonstrated the luminescence of the embedded quantum dots is preserved and the loss of these hybrid waveguide wires is as low as 2.69dB/cm at 900nm wavelength. This hybrid i...

We demonstrate a technique for the precise immobilization of nanoscale objects at accurate positions on two-dimensional surfaces. We have developed a water-based photoresist that causes nanostructures such as colloidal quantum dots to segregate to a thin layer at surfaces. By combining this material with electroosmotic feedback control, we demonstrate the ability to position selected, individua...

up an entire field of interdisciplinary research! Although foundational research into nano-scaled semiconductors was already underway by 1973 when Leo Esaki won the Nobel Prize in Physics for his work on semiconductor quantum devices, quantum dots were not recognized for their biological applications until the pioneering papers of the Alivisatos lab and the Nie lab in 1998 [1]. In these papers,...

Vertically aligned single crystalline ZnO nanorod arrays, approximately 3 μm in length and 50-450 nm in diameter are grown by a simple solution approach on a Zn foil substrate. CdS and CdSe colloidal quantum dots are assembled onto ZnO nanorods array using water-soluble nanocrystals capped as-synthesized with a short-chain bifuncional linker thioglycolic acid. The solar cells co-sensitized with...

Number of Papers published in peer-reviewed journals: Final Report: Transformative Colloidal Nanomaterials for Mid-Infrared Devices Report Title The grant focused on the Photoluminescence efficiency of HgTe colloidal quantum dots. The photoluminescence quantum yield of HgTe colloidal quantum dots was measured from 1800 to 6500 cm-1 . There is a steep drop at low energy consistent with the gener...