16 research outputs found
High-efficiency perovskite–polymer bulk heterostructure light-emitting diodes
Perovskite-based optoelectronic devices have gained significant attention due
to their remarkable performance and low processing cost, particularly for solar
cells. However, for perovskite light-emitting diodes (LEDs), non-radiative
charge carrier recombination has limited electroluminescence (EL) efficiency.
Here we demonstrate perovskite-polymer bulk heterostructure LEDs exhibiting
record-high external quantum efficiencies (EQEs) exceeding 20%, and an EL
half-life of 46 hours under continuous operation. This performance is achieved
with an emissive layer comprising quasi-2D and 3D perovskites and an insulating
polymer. Transient optical spectroscopy reveals that photogenerated excitations
at the quasi-2D perovskite component migrate to lower-energy sites within 1 ps.
The dominant component of the photoluminescence (PL) is primarily bimolecular
and is characteristic of the 3D regions. From PL quantum efficiency and
transient kinetics of the emissive layer with/without charge-transport
contacts, we find non-radiative recombination pathways to be effectively
eliminated. Light outcoupling from planar LEDs, as used in OLED displays,
generally limits EQE to 20-30%, and we model our reported EL efficiency of over
20% in the forward direction to indicate the internal quantum efficiency (IQE)
to be close to 100%. Together with the low drive voltages needed to achieve
useful photon fluxes (2-3 V for 0.1-1 mA/cm2), these results establish that
perovskite-based LEDs have significant potential for light-emission
applications
Neue Bauelementtechnologie zur Vereinheitlichung von Prozessschritten und zur Verbesserung des Wirkungsgrades von lichtemittierenden Dioden
SIGLEDEGerman
Laser fuer Teilnehmeranschluss
With 63 refs., 49 figs.SIGLETIB: FR 1439+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman