Andaji-Garmaroudi, Z;
Abdi-Jalebi, M;
Kosasih, FU;
Doherty, T;
Macpherson, S;
Bowman, AR;
Man, GJ;
... Stranks, SD; + view all
(2020)
Elucidating and Mitigating Degradation Processes in Perovskite Light‐Emitting Diodes.
Advanced Energy Materials
, 10
(48)
, Article 2002676. 10.1002/aenm.202002676.
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Abstract
Halide perovskites have attracted substantial interest for their potential as disruptive display and lighting technologies. However, perovskite light‐emitting diodes (PeLEDs) are still hindered by poor operational stability. A fundamental understanding of the degradation processes is lacking but will be key to mitigating these pathways. Here, a combination of in operando and ex situ measurements to monitor the performance degradation of (Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3 PeLEDs over time is used. Through device, nanoscale cross‐sectional chemical mapping, and optical spectroscopy measurements, it is revealed that the degraded performance arises from an irreversible accumulation of bromide content at one interface, which leads to barriers to injection of charge carriers and thus increased nonradiative recombination. This ionic segregation is impeded by passivating the perovskite films with potassium halides, which immobilizes the excess halide species. The passivated PeLEDs show enhanced external quantum efficiency (EQE) from 0.5% to 4.5% and, importantly, show significantly enhanced stability, with minimal performance roll‐off even at high current densities (>200 mA cm−2). The decay half‐life for the devices under continuous operation at peak EQE increases from <1 to ≈15 h through passivation, and ≈200 h under pulsed operation. The results provide generalized insight into degradation pathways in PeLEDs and highlight routes to overcome these challenges.
| Type: | Article |
|---|---|
| Title: | Elucidating and Mitigating Degradation Processes in Perovskite Light‐Emitting Diodes |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/aenm.202002676 |
| Publisher version: | https://doi.org/10.1002/aenm.202002676 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | degradation, halide perovskites, ion migration, light‐emitting diodes, passivation |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > MAPS Faculty Office UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > MAPS Faculty Office > Institute for Materials Discovery |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10118123 |
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