Abstract
AbstractColloidal inorganic perovskite nanocrystals (PNCs) are solution‐processable optoelectronic materials whose emission can be easily tuned via both size and composition while maintaining high photoluminescence quantum yield. Despite their relative defect tolerance, they suffer from photoinduced damage and degradation under ambient conditions. The lack of long‐term stability is addressed by investigating how a ≈3 nm transparent ceramic coating applied onto a thin layer of close‐packed PNCs via atomic layer deposition (ALD) affects the exciton mobility across the PNCs. Samples coated via both thermal and plasma ALD are compared, as well as an uncoated one. Exciton diffusion measurements yield a record value for all samples, up to λD = 480 ± 24 nm, one order of magnitude larger than the previously reported values for chalcogenide quantum dots and more than two times larger than what was previously found for the PNCs. Moreover, the ALD‐coated samples show stable photoluminescence intensity and energy over 1 year time span. The measurement approach allows for discerning minimal variations in the local luminescence and qualitatively correlating them to the samples’ morphology. Hence, it is shown that PNCs coated with an ultrathin ALD film become a very versatile optoelectronic material that can be employed in devices beyond proof of principle.
Highlights
One way to assess their potential for optoelectronics application is by investigating their exciton transport with excitonPerovskite nanocrystals (PNCs) have recently become the sub- diffusion measurements
The transparent Al2O3 layer greatly increased the preservation of the PNCs optical properties, as demonstrated by comparison to an uncoated sample
Considering that perovskite materials undergo irreversible degradation due to air and humidity, and that our samples were stored in air at room temperature, this result demonstrated the applicability of this system for optoelectronic devices
Summary
Perovskite nanocrystals (PNCs) have recently become the sub- diffusion measurements. Exciton diffusion mediated by ject of intense research efforts.[1,2] After the first report of their Förster resonance energy transfer (FRET) is responsible for very efficient energy transport in several processes in nature, Dr M. In order to promote this, one needs to implement strategies to maintain the optical stability over time In this manuscript, we expand the work we did in the previous work[13] by comparing samples with two differently processed protective coatings. We coated them with a 3 nm thick layer of alumina, deposited by either thermal[19a,20] or plasma[21] assisted ALD, in order to address some critical issues: 1) achieving a long-term stability (up to 1 year) of both optical and structural properties; and 2) ensuring that these properties are not affected by the deposition process. The high resolution of our setup allowed us to discern slight, but very relevant, differences between them, while recording an exceptional diffusion length of over 400 nm We found that both the plasma and the thermal processes provide an effective coating that preserved the PNC optical properties. The exceptional exciton diffusion lengths recorded for our ALD-coated PNCs films constitutes a remarkable result towards their actual integration into photonic and optoelectronic devices
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
