Erratum: “Spatially resolved study of quantum efficiency droop in InGaN light-emitting diodes,” [Appl. Phys. Lett. 101, 252103 (2012)]

We investigated the effects of different well shapes on the external quantum efficiency (EQE) and the efficiency droop in wide-well InGaN/GaN double-heterostructure light-emitting diodes. For forward current densities in the measurement range of greater than 135 A/cm2, the device featuring a trapezoidal well exhibited improved EQEs and alleviative efficiency droop, relative to those of the device featuring a rectangular well. The decreased Auger loss has been proposed as the main reason for the greater maximum efficiency that occurred at high current density (>50 A/cm2). For the devices incorporating trapezoidal and rectangular wells, the EQEs at 200 A/cm2decreased by 14 and 40%, respectively, from their maximum values, resulting in the EQE at a current density of 200 A/cm2of the device featuring a trapezoidal well being 17.5% greater than that featuring a rectangular well. These results suggest that, in addition to the decreased Auger loss, the alleviation in efficiency droop at higher current densities might be due to higher internal quantum efficiency resulted from the improved carrier injection efficiency of the trapezoidal well.

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Phenylalkylammonium passivation enables perovskite light emitting diodes with record high-radiance operational lifetime: the chain length matters

Nature Communications ◽

10.1038/s41467-021-20970-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yuwei Guo ◽

Sofia Apergi ◽

Nan Li ◽

Mengyu Chen ◽

Chunyang Yin ◽

...

Keyword(s):

Chain Length ◽

Quantum Efficiency ◽

External Quantum Efficiency ◽

Light Emitting Diodes ◽

Surface Defects ◽

Theoretical Modelling ◽

Ion Migration ◽

Light Emitting ◽

Operational Lifetime ◽

Chain Lengths

AbstractPerovskite light emitting diodes suffer from poor operational stability, exhibiting a rapid decay of external quantum efficiency within minutes to hours after turn-on. To address this issue, we explore surface treatment of perovskite films with phenylalkylammonium iodide molecules of varying alkyl chain lengths. Combining experimental characterization and theoretical modelling, we show that these molecules stabilize the perovskite through suppression of iodide ion migration. The stabilization effect is enhanced with increasing chain length due to the stronger binding of the molecules with the perovskite surface, as well as the increased steric hindrance to reconfiguration for accommodating ion migration. The passivation also reduces the surface defects, resulting in a high radiance and delayed roll-off of external quantum efficiency. Using the optimized passivation molecule, phenylpropylammonium iodide, we achieve devices with an efficiency of 17.5%, a radiance of 1282.8 W sr−1 m−2 and a record T50 half-lifetime of 130 h under 100 mA cm−2.

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New Results on Electroluminescence from Porous Silicon

MRS Proceedings ◽

10.1557/proc-283-343 ◽

1992 ◽

Vol 283 ◽

Cited By ~ 22

Author(s):

Peter Steiner ◽

Frank Kozlowski ◽

Hermann Sandmaier ◽

Walter Lang

Keyword(s):

Porous Silicon ◽

Quantum Efficiency ◽

Light Emitting Diodes ◽

Uv Light ◽

Green Light ◽

Light Emitting ◽

Porous Region ◽

First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

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