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.
keywords
LIGHT-EMITTING-DIODES; ORIENTATION; ABSORPTION; EFFICIENCY; ENERGY
subject category
Science & Technology - Other Topics; Materials Science
authors
Scott, R; Heckmann, J; Prudnikau, AV; Antanovich, A; Mikhailov, A; Owschimikow, N; Artemyev, M; Climente, JI; Woggon, U; Grosse, NB; Achtstein, AW
our authors
Aliaksandr Mikhailau
PhD StudentGroups
acknowledgements
R.S., U.W. and A.W. A acknowledge DFG grants WO477-1/32 and AC290-1/1 and 2/1. J.I.C. acknowledges support from MINECO project CTQ2014-60178-P and UJI project P1-1B2014-24, M.A. from the CHEMREAGENTS program and A.A. from BRFFI grant no. X16M-020.