Abstract
Nanocrystal (NC) solids are an exciting class of materials, whose physical properties are tunable by choice of the NCs as well as the strength of the interparticle coupling. One can consider these NCs as "artificial atoms" in analogy to the formation of condensed matter from atoms. Akin to atomic doping, the doping of a semiconducting NC solid with impurity NCs can drastically alter its electronic properties. A high degree of complexity is possible in these artificial structures by adjusting the size, shape, and composition of the building blocks, which enables "designer" materials with targeted properties. Here, we present the doping of the PbSe NC solids with a series of AuxAg1-x alloy nanoparticles (NPs). A combination of temperature-dependent electrical conductance and Seebeck coefficient measurements and room-temperature Hall effect measurements demonstrates that the incorporation of metal NPs both modifies the charge carrier density of the NC solids and introduces energy barriers for charge transport. These studies point to charge carrier injection from the metal NPs into the PbSe NC matrix. The charge carrier density and charge transport dynamics in the doped NC solids are adjustable in a wide range by employing the AuxAg1-x NP with different Au:Ag ratio as dopants. This doping strategy could be of great interest for thermoelectric applications taking advantage of the energy filtering effect introduced by the metal NPs.
| Original language | English |
|---|---|
| Pages (from-to) | 9091-9100 |
| Number of pages | 10 |
| Journal | ACS Nano |
| Volume | 12 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 25 2018 |
Funding
The primary support of this project was provided by The Nature Conservancy and the generosity of Sarah W. Fuller through a Nature Net Science Fellowship awarded to H.Y. E.W., T.Z., H.Y.T., and C.R.K. were supported in their contributions to the electrical characterization by the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. J.D.L.’s materials effort in characterization was supported by Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DE-SC0001004. B.F. and E.A.G. were supported in materials synthesis and character- ization supported by NSF through the University of Pennsylvania Materials Research Science and Engineering Center (MRSEC) (DMR-1720530) and through the use of facilities and instrumentation maintained under this award. M.C. acknowledges the support from ORNL’s Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.
| Funders | Funder number |
|---|---|
| CNMS | |
| Catalysis Center for Energy Innovation | |
| ORNL’s Center for Nanophase Materials Sciences | |
| Office of Basic Energy Sciences | |
| Scientific User Facilities Division | |
| University of Pennsylvania Materials Research Science and Engineering Center | |
| National Science Foundation | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| Materials Research Science and Engineering Center, Harvard University | DMR-1720530 |
| Nature Conservancy |
Keywords
- charge transport
- doping
- gold silver alloy nanoparticles
- lead selenide nanocrystals
- nanocrystal solids
- thermoelectric