Temperature Dependent Photoluminescence of Size-Purified Silicon Nanocrystals
详细信息 查看全文
- 作者：Austin R. Van Sickle ; Joseph B. Miller ; Christopher Moore ; Rebecca J. Anthony ; Uwe R. Kortshagen ; Erik K. Hobbie
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2013
- 出版时间：May 22, 2013
- 年：2013
- 卷：5
- 期：10
- 页码：4233-4238
- 全文大小：388K
- 年卷期：v.5,no.10(May 22, 2013)
- ISSN：1944-8252
文摘
The photoluminescence (PL) of size-purified silicon nanocrystals is measured as a function of temperature and nanoparticle size for pure nanocrystal films and polydimethylsiloxane (PDMS) nanocomposites. The temperature dependence of the bandgap is the same for both sample types, being measurably different from that of bulk silicon because of quantum confinement. Our results also suggest weaker interparticle and environmental coupling in the nanocomposites, with enhanced PL and an unexpected dependence of lifetime on size for the pure nanocrystal films at low temperatures. We interpret these results through differences in the low-temperature size dependence of the ensemble nonradiative equilibrium constants. The response of the PDMS nanocomposites provides a consistent measure of local temperature through intensity, lifetime, and wavelength in a polymer-dispersed morphology suitable for biomedical applications, and we exploit this to fabricate a small-footprint fiber-optic cryothermometer. A comparison of the two sample types offers fundamental insight into the photoluminescent behavior of silicon nanocrystal ensembles.