Nondestructive Direct Optical Patterning of Perovskite Nanocrystals with Carbene-Based Ligand Cross-Linkers

Abstract

Microscale patterning of colloidal perovskite nanocrystals (NCs) is essential for their integration in advanced device platforms, such as high-definition displays. However, perovskite NCs usually show degraded optical and/or electrical properties after patterning with existing approaches, posing a critical challenge for their optoelectronic applications. Here we achieve nondestructive, direct optical patterning of perovskite NCs with rationally designed carbene-based cross-linkers and demonstrate their applications in high-performance lightemitting diodes. We reveal that both the photochemical properties and the electronic structures of cross-linkers need to be carefully tailored to the material properties of perovskite NCs. This method produces high-resolution (∼4000 ppi) NC patterns with preserved photoluminescent quantum efficiencies and charge transport properties. Prototype light-emitting diodes with patterned/cross-linked NC layers show a maximum luminance of over 60000 cd m −2 and a peak external quantum efficiency of 16%, among the highest for patterned perovskite electroluminescent devices. Such a material-adapted patterning method enabled by designs from a photochemistry perspective could foster the applications of perovskite NCs in system-level electronic and optoelectronic devices.

Advances in Quantum Dot Direct Photolithographic Patterning

“…Copyright 2020 American Chemical Society; (c) PXLs with pyrrolidinyl (−N­(CH 2 ) 4 ), oxy (−O−), and thio (−S−) groups by Donghyo Hahm et al, reprinted with permission from ref under CC-BY license; (d) 3,3′-(4,4′-(perfluorobutane-1,4-diyl)­bis­(4,1-phenylene))­bis­(3-(trifluoromethyl)-3H-diazirine. Reprinted with permission from ref . Copyright 2024 American Chemical Society; (e) PAG molecules.…”

“…Taking the combination of CdSe NCs owning solely OA ligands with (1E,4E)-1,5-bis­(4-azido-2,3,5,6-tetrafluorophenyl)­penta-1,4-dien-3-one as an example, even 50 mJ cm –2 dose for 5–10 mol % of the cross-linker could achieve high film retention, as shown in Figure c. Meanwhile, their proposed carbene-based cross-linker named 3,3′-(4,4′-(perfluorobutane-1,4-diyl)­bis­(4,1-phenylene))­bis (3-(trifluoromethyl)-3H-diazirine containing two diazirine moieties could also connect the natural ligands on PNCs by nonspecific C–H insertion, thus achieving the nondestructive patterning of PNCs while better preserving the PL properties of CPB NCs …”

“…In addition, the device characteristics of PNC LEDs realized via the thiol–ene click reaction are also not adversely affected by PTMP addition and subsequent patterning processes . Recently, patterned PNC LEDs have broken new ground with a maximum luminance value and peak EQE value, beyond 60,000 cd m –2 and 16%, respectively . Additionally, the photopatterning method of heavy-metal-free QDs showed that the patterned film acted as the emissive layer and this photo-cross-linking process did not affect the optical and electrical characteristics of QD films .…”