Photoluminescence (PL) spectra were measured for dodecene-capped Si nanocrystals with a wide range of average diameters, from 1.8 to 9.1 nm. Nanocrystals larger than 3 nm exhibited relatively high PL quantum yields of 30%−45%. Smaller nanocrystals exhibited lower quantum yields that decreased significantly with reduced size. Because smaller nanocrystals also have lower optical absorption there is a significant biasing of the PL spectra by the larger nanocrystals. We show that with proper accounting of polydispersity and size- dependent quantum yields and optical absorption the effective mass approximation (EMA) accurately estimates the average diameter of silicon (Si) nanocrystals from experimentally determined PL emission peak energies. A finite confinement model is presented that explains the decreased PL quantum yields of the smaller diameter nanocrystals.
Size-Dependent Photoluminescence Efficiency of Silicon Nanocrystal Quantum Dots
FERMI, ANDREA;MAZZARO, RAFFAELLO;CERONI, PAOLA;
2017
Abstract
Photoluminescence (PL) spectra were measured for dodecene-capped Si nanocrystals with a wide range of average diameters, from 1.8 to 9.1 nm. Nanocrystals larger than 3 nm exhibited relatively high PL quantum yields of 30%−45%. Smaller nanocrystals exhibited lower quantum yields that decreased significantly with reduced size. Because smaller nanocrystals also have lower optical absorption there is a significant biasing of the PL spectra by the larger nanocrystals. We show that with proper accounting of polydispersity and size- dependent quantum yields and optical absorption the effective mass approximation (EMA) accurately estimates the average diameter of silicon (Si) nanocrystals from experimentally determined PL emission peak energies. A finite confinement model is presented that explains the decreased PL quantum yields of the smaller diameter nanocrystals.File | Dimensione | Formato | |
---|---|---|---|
jp7b08054_si_001.pdf
accesso aperto
Tipo:
File Supplementare
Licenza:
Licenza per accesso libero gratuito
Dimensione
1.26 MB
Formato
Adobe PDF
|
1.26 MB | Adobe PDF | Visualizza/Apri |
Size-dep_accept_man.pdf
Open Access dal 22/09/2018
Tipo:
Postprint
Licenza:
Licenza per accesso libero gratuito
Dimensione
1.82 MB
Formato
Adobe PDF
|
1.82 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.