On the Physical Nature of Few-Carrier Plasmon Resonances Prashant ...
SUPPORTING INFORMATION Plasmon-in-a-Box: On the Physical Nature of Few-Carrier Plasmon Resonances Prashant K. Jain* Department of Chemistry and Materials Research Lab, University of Illinois UrbanaChampaign, Urbana, Illinois 61801, United States Corresponding Author *Email: [email protected]
S1
Au nanospheres of 13 nm size
Figure S1. The plasmon resonance extinction spectrum calculated using the theoretical model (blue) agrees with an experimental spectrum (red) for colloidal Au nanospheres of 13-nm size. The medium refractive index was set as 1.33, close to that of water, which is the medium of the Au nanosphere colloid. The electron density used in the calculation was 5.7 x 1028 m-3 close to the value of 5.9 x 1028 m-3 for Au. ε∞ = 12, close to that known for Au.1 meff = 9.1 x 10-31 kg, the value for a free electron and γ = 13π x 1013 rad/s. Note the spectra are presented on an arbitrary absorbance scale in order to facilitate comparison.
Cu2-xSe nanocrystals of 16 nm size
Figure S2. The plasmon resonance extinction spectrum calculated using the theoretical model (blue) agrees with an experimental spectrum (red) for Cu2-xSe nanocrystals. The experimental spectrum was digitized from the work of Deka et al. (Fig 4a).2 The nanocrystal size was set as 16 nm, as reported in the experiment. The medium refractive index was set as 1.45, close to that of typical organic ligands/solvents. Calculations were performed for a hole density of 3 x 1027 m-3, which amounts to a 12% Cu vacancy level or a stoichiometry of Cu1.76Se, which is within the range Cu1.68Se to Cu1.80Se cited in the experiment.2 ε∞ = 7 and meff = 0.4me, close to that known for cuprous selenide.3 γ = 18π x 1013 rad/s. Note the spectra are presented on an arbitrary absorbance scale in order to facilitate comparison.
S2
Supporting References 1. Johnson, P. B.; Christy, R. W. Optical Constants of the Noble Metals. Phys. Rev. B 1972, 6, 4370 2. Deka, S.; Genovese, A.; Zhang, Y.; Miszta, K.; Bertoni, G.; Krahne, R.; Giannini, C.; Manna, L. Phosphine-Free Synthesis of p-Type Copper(I) Selenide Nanocrystals in Hot Coordinating Solvents. J. Am. Chem. Soc. 2010, 132, 8912–8914, 3. Mansour, B. A.; Demian, S. E.; Zayed, H. A. Determination of the Effective Mass for Highly Degenerate Copper Selenide from Reflectivity Measurements. J. Mater. Sci. Mater. Electron. 1992, 3, 249-252.
S3
S1
Au nanospheres of 13 nm size
Figure S1. The plasmon resonance extinction spectrum calculated using the theoretical model (blue) agrees with an experimental spectrum (red) for colloidal Au nanospheres of 13-nm size. The medium refractive index was set as 1.33, close to that of water, which is the medium of the Au nanosphere colloid. The electron density used in the calculation was 5.7 x 1028 m-3 close to the value of 5.9 x 1028 m-3 for Au. ε∞ = 12, close to that known for Au.1 meff = 9.1 x 10-31 kg, the value for a free electron and γ = 13π x 1013 rad/s. Note the spectra are presented on an arbitrary absorbance scale in order to facilitate comparison.
Cu2-xSe nanocrystals of 16 nm size
Figure S2. The plasmon resonance extinction spectrum calculated using the theoretical model (blue) agrees with an experimental spectrum (red) for Cu2-xSe nanocrystals. The experimental spectrum was digitized from the work of Deka et al. (Fig 4a).2 The nanocrystal size was set as 16 nm, as reported in the experiment. The medium refractive index was set as 1.45, close to that of typical organic ligands/solvents. Calculations were performed for a hole density of 3 x 1027 m-3, which amounts to a 12% Cu vacancy level or a stoichiometry of Cu1.76Se, which is within the range Cu1.68Se to Cu1.80Se cited in the experiment.2 ε∞ = 7 and meff = 0.4me, close to that known for cuprous selenide.3 γ = 18π x 1013 rad/s. Note the spectra are presented on an arbitrary absorbance scale in order to facilitate comparison.
S2
Supporting References 1. Johnson, P. B.; Christy, R. W. Optical Constants of the Noble Metals. Phys. Rev. B 1972, 6, 4370 2. Deka, S.; Genovese, A.; Zhang, Y.; Miszta, K.; Bertoni, G.; Krahne, R.; Giannini, C.; Manna, L. Phosphine-Free Synthesis of p-Type Copper(I) Selenide Nanocrystals in Hot Coordinating Solvents. J. Am. Chem. Soc. 2010, 132, 8912–8914, 3. Mansour, B. A.; Demian, S. E.; Zayed, H. A. Determination of the Effective Mass for Highly Degenerate Copper Selenide from Reflectivity Measurements. J. Mater. Sci. Mater. Electron. 1992, 3, 249-252.
S3
