CC BY
29LD-I-10
Spectral and temporal characteristics of silicon quantum dot luminescence and their application in light conversion
I. Sychugov1
1KTH Royal Institute of Technology, Applied Physics, Stockholm, Sweden
Strong size-dependent properties of nanocrystal quantum dots stipulate targeting individual particles for the investigation of their basic properties [1]. In this talk fundamental parameters of the light emission from silicon quantum dots will be summarized as deduced from single-dot emission, absorption and lifetime measurements [2-7]. In particular, emission and absorption states in individual silicon nanocrystals were studied by temperature-dependent photoluminescence and photoluminescence excitation experiments. Both close-to-spherical and elongated particles were probed and the results were compared to first-principle calculation. The comparison revealed good agreement with theory, where the intermixing of direct and indirect states in nanostructured silicon takes place as a function of nanoparticle size, shape and photon energy. Next, some applications of silicon nanocrystal quantum dots in light-conversion applications will be summarized [8-10]. An important feature of such nanoparticles is a large Stokes shift, stemming from the bulk material energy structure. This property makes these fluorophores good candidates for some light converting applications, such as in luminescent solar concentrators [10]. We have prepared hybrid materials with different polymers, where enhancement of quantum yield up to 60-70% was recorded in case of off-stochiometry thiols, attributed to dangling bond passivation by polymer radicals. The resulting nanoparticle-polymer hybrids were successfully integrated with glass and their stability over months was demonstrated [9].
References
[1] I. Sychugov, J. Valenta, J. Linnros, Probing Silicon Quantum Dots by Single-dot Techniques, Nanotechnology, 28 (2017) 072002.
[2] I. Sychugov, F. Pevere, J.W. Luo, A. Zunger, J. Linnros, Single-dot Absorption Spectroscopy and Theory of Silicon Nanocrystals, Phys. Rev. B, 93 (2016).
[3] I. Sychugov, F. Sangghaleh, B. Bruhn, F. Pevere, J.-W. Luo, A. Zunger, J. Linnros, Strong Absorption Enhancement in Si Nanorods, Nano Lett., 16 (2016) 7937-7941.
[4] J.W. Luo, S.S. Li, I. Sychugov, F. Pevere, J. Linnros, A. Zunger, Absence of Red-shift in the Direct Band Gap of Silicon Nanocrystals with Reduced Size, Nat. Nanotechnol., 12 (2017) 930-932.
[5] F. Pevere, F. Sangghaleh, B. Bruhn, I. Sychugov, J. Linnros, Rapid trapping as the origin of non-radiative recombination in semiconductor nanocrystals, ACS Photon., 5 (2018) 2990-2996.
[6] F. Pevere, C. von Treskow, E. Marino, M. Anwar, B. Bruhn, I. Sychugov, J. Linnros, X-ray radiation hardness and influence on blinking in Si and CdSe quantum dots, Appl. Phys. Lett., 113 (2018) 253103.
[7] M. Greben, P. Khoroshyy, I. Sychugov, J. Valenta, Non-exponential decay kinetics: Correct assessment and description illustrated by slow luminescence of Si nanostructures, Appl. Spectrosc. Rev., 54 (2019) 1-44.
[8] A. Marinins, Z. Yang, H. Chen, J. Linnros, J.G.C. Veinot, S. Popov, I. Sychugov, Photostable Polymer/Si Nanocrystal Bulk Hybrids with Tunable Photoluminescence, ACS Photon., 3 (2016) 1575.
[9] A. Marinins, R. Shafagh, W. Van der Wijngaart, T. Haraldsson, J. Linnros, J.G.C. Veinot, S. Popov, I. Sychugov, Light Converting Polymer/Si Nanocrystal Composites with Stable 60-70% Efficiency and their Glass Laminates, ACS Appl. Mater. Interfaces, 9 (2017) 30267-30272.
[10] I. Sychugov, Analytical Description of a Luminescent Solar Concentrator Device, arxiv: 1903.03788, (2019).
