Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure

authors	Scott, R; Heckmann, J; Prudnikau, AV; Antanovich, A; Mikhailov, A; Owschimikow, N; Artemyev, M; Climente, JI; Woggon, U; Grosse, NB; Achtstein, AW
nationality	International
journal	NATURE NANOTECHNOLOGY
keywords	LIGHT-EMITTING-DIODES; ORIENTATION; ABSORPTION; EFFICIENCY; ENERGY
abstract	Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energyefficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters.
publisher	NATURE PUBLISHING GROUP
issn	1748-3387
year published	2017
volume	12
issue	12
beginning page	1155
ending page	+
digital object identifier (doi)	10.1038/NNANO.2017.177
web of science category	Nanoscience & Nanotechnology; Materials Science, Multidisciplinary
subject category	Science & Technology - Other Topics; Materials Science
unique article identifier	WOS:000417280400019