Semiconductor Nanocrystal Optoelectronics: from colloidal Quantum Dots to Wells

Hilmi Volkan Demir^a^,^b

^aDepartment of Electrical and Electronics Engineering, Department of Physics, and UNAM–Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey.

^bNTU Singapore – Nanyang Technological University, School of Electrical Engineering, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Singapore

Proceedings of Internet Conference for Quantum Dots (iCQD)

Online, Spain, 2020 July 14th - 17th

Organizers: Quinten Akkerman, Raffaella Buonsanti, Zeger Hens and Maksym Kovalenko

Invited Speaker, Hilmi Volkan Demir, presentation 055
Publication date: 3rd July 2020

Solution-processed semiconductor nanocrystals have been attracting increasingly greater interestin photonicsincluding spectrally pure color conversion and enrichment in quality lighting and display backlighting [1,2]. These nanocrystals span different types and structures of semiconductors in the forms of colloidal quantum dots and rods to a more recently developing class of colloidal quantum wells. In this talk, we will introduce the emerging field of nanocrystal optoelectronics using solution-processed, efficient, quantum emitters: through the journey of colloidal quantum dots to wells. In particular, we will present a new concept of all-colloidal lasers developed by incorporating nanocrystal emitters as the optical gain media, intimately integrated into fully colloidal cavities [3]. In the talk, we will then focus on our recent work on the latest rising star of tightly-confined atomically-flat nanocrystals, the quasi-2D colloidal quantum wells (CQWs), also popularly nick-named ‘nanoplatelets’. Among various extraordinary features of these CQWs, we will present our most recent discovery that the CQWs uniquely enable record high optical gain coefficients among all colloids [4]. In addition, we will show our results on the controlled stacking and assemblies of these nanoplatelets, which provides us with the ability to tune and master their excitonic properties [5], present the first accounts of doping them for high-flux solar concentration and precise wavefunction-engineered magnetic properties [6], and our record high-efficiency LEDs [7]. Given their current accelerating progress, these solution-processed quantum materials hold great promise to challenge their epitaxial thin-film counterparts in semiconductor optoelectronics in the nearfuture.

References:

[1] H. V. Demir et al., Nano Today 6, 632(2011)

[2] E. Mutlugün et al., Nano Letters 12, 3986 (2012); T. Özel et al., Nano Letters 13, 3065 (2013); X. Yang et al., ACS Nano 8, 8224 (2014)

[3] B. Güzeltürk et al., Advanced Materials 27, 2741 (2015); B. Güzeltürk et al., ACS Nano 8, 6599 (2014)

[4] B. Güzeltürk et al., Nano Letters 19, 277(2019)

[5] O. Erdem et al., Nano Letters 19, 4297 (2019); N. Taghipour et al., ACS Nano 12, 8547 (2018); F. Muckel et al., Nano Letters 18, 2047 (2018)

[6] M. Sharma et al., Advanced Materials 29, 1700821 (2017); M. Sharma et al., Chemistry of Materials 30, 3265 (2018)

[7] B. Liu et al., Advanced Materials, 32, 1905824 (2020)

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