Peer review of: Transparent near-infrared perovskite light-emitting diodes (2023)

REVIEWER COMMENTS 

Reviewer #1 (Remarks to the Author): 

In this manuscript, Xie et al. fabricate a large-area, transparent NIR perovskite LED and demonstrate 
its potential applications as illumination integrated in a color display. This provides a new strategy for 
the light source in large-area, flexible wearable devices. In general, this is an very interesting work. I 
would recommend acceptance of this manuscript after minor revision. 
1. I am curious why the transparent device has a low EQE of 5.7% with device area of 120 mm2. In 
their previous work (Nature Photonics, 14, 215-218 (2020)), they already demonstrate 12.1% EQE of 
900 mm2 LEDs with conventional architecture. Is this due to the absorption of top electrode or the 
degradation of device during the multi-scans? 
2. The authors should provide the statistic of device efficiency. 
3. Could the authors use other transparent electrodes to replace the Al/ITO/Ag/ITO? The 55% 
transmittance is not good enough for transparent LED application. 
4. It might be helpful if the authors could provide the optimization process of the top electrode. 



Reviewer #2 (Remarks to the Author): 

This work is very interesting and would potentially meet the standards for publication on Nature 
Communications. However, some revisions are needed before acceptation. 

In this manuscript the Authors reported a transparent perovskite light-emitting diode (LED) that could 
be overlaid across an emissive colour display to provide efficient and high-intensity covert NIR 
illumination. The devices presented here are constructed with an ITO/AZO/PEIE/FAPbI3/poly-
TPD/MoO3/Al/ITO/Ag/ITO architecture, and offer a high average transmittance of more than 55% 
across the visible spectral region. In particular, the Al/ITO/Ag/ITO top transparent electrode was 
designed to offer a combination low sheet resistance and low plasma damage during device fabrication. 
The devices emit at 799 nm with a high total external quantum efficiency of 5.7% at a current density 
of 5.3 mA cm-2 and a high radiance of 1.5 W sr-1 m-2, and possess a large functional device area of 
120 mm2. This report represents and advancement of the perovskite-based light emitting devices as it 
could be integrated in battery-powered wearable devices, and could enable new security and remote 
sensing features on future smart-watches, phones and augmented or virtual reality headsets. The 
approach is then very interesting and novel to suits the standards for publication on Nature 
communications, although the work requires some clarifications/modification to finally express the 
research potential. 

Specific comments 
- The authors shown and discussed how the Al/ITO back electrode perform better than the pristine 
sputtered ITO, further reasoning about a process (sputtering) driven degradation of the perovskite 
layer. However alternative effects could take place in justifying the observation, particularly due to the 
reflective nature of the Al layer potentially leading to cavity effects. Could the authors deepen their 
claim? We suggest adding some structural (XRD) and optical measurements (PL and time resolved PL) 
to show how the ITO sputtering is really reducing the quality of the perovskite film. 
- Related to this point we believe the characterization of the perovskite material is somehow missing 
in this work, and we are sure the addition of data in this regard could beneficially affect the impact 
and the soundness of the work. 
- We are wondering if the authors tested the structural nature and stability of the FAPbI3 perovskite, it 
is well known the polymorphism of this compound and the need of using elevated annealing 
temperature to obtain the optoelectronic active alpha phase. Since the authors used only 100 °C 
annealing temperature they should also show and discuss some XRD results. 
- What is the thickness of the perovskite active layer in those devices? Did the authors screen the 
devices performances of differently thick active layers? 
- Did the Authors test the stability of their devices? 



Reviewer #3 (Remarks to the Author): 

The authors report on the fabrication of semi-transparent NIR emitting perovskite LEDs. Although I 
find the work interesting, I believe that it cannot be accepted for publication in Nature 
Communications. Following the issues: 
1) The work looks a mere exercise of device optimization; 
2) The literature context is not well explained; 
3) The English need a revision.