Direct Patterning of CsPbBr3 Nanocrystals via Electron-Beam Lithography.

Christian D Dieleman,Erik C Garnett,Neha Thakur,Julia Van Der Burgt,Bruno Ehrler

doi:10.1021/acsaem.1c03091

Abstract

Lead-halide perovskite (LHP) nanocrystals have proven themselves as an interesting material platform due to their easy synthesis and compositional versatility, allowing for a tunable band gap, strong absorption, and high photoluminescence quantum yield (PLQY). This tunability and performance make LHP nanocrystals interesting for optoelectronic applications. Patterning active materials like these is a useful way to expand their tunability and applicability as it may allow more intricate designs that can improve efficiencies or increase functionality. Based on a technique for II–VI quantum dots, here we pattern colloidal LHP nanocrystals using electron-beam lithography (EBL). We create patterns of LHP nanocrystals on the order of 100s of nanometers to several microns and use these patterns to form intricate designs. The patterning mechanism is induced by ligand cross-linking, which binds adjacent nanocrystals together. We find that the luminescent properties are somewhat diminished after exposure, but that the structures are nonetheless still emissive. We believe that this is an interesting step toward patterning LHP nanocrystals at the nanoscale for device fabrication.

Highlights

Perovskite nanocrystals are an interesting material platform for a diverse range of applications
This allows perovskite nanocrystals to be suitable for many applications including photovoltaics,[10,11] photodetectors,[12,13] scintillators,[14,15] and light-emitting diodes (LEDs).[16−18] The wide applicability is enabled because perovskites can be efficient emitters, exhibiting long charge-carrier lifetimes and defect resistance
We showed a method to pattern colloidal quantum dots (CQDs) directly by extreme UV lithography (EUVL) or ebeam lithography (EBL) without affecting their luminescent properties significantly.[22]

Summary

Introduction

Perovskite nanocrystals are an interesting material platform for a diverse range of applications. By replacing cations, one can form methylammonium-based[7] or formamidinium-based[8] perovskite nanocrystals, and the often-used lead metal can be replaced to form tin-based perovskites.[9] Organic ligands, which passivate the surface of the crystals and provide colloidal stability, can influence the electronic environment of the nanocrystals and alter the shape during synthesis This allows perovskite nanocrystals to be suitable for many applications including photovoltaics,[10,11] photodetectors,[12,13] scintillators,[14,15] and light-emitting diodes (LEDs).[16−18] The wide applicability is enabled because perovskites can be efficient emitters, exhibiting long charge-carrier lifetimes and defect resistance. We expanded this method to include perovskite nanocrystals and show that these crystals can be patterned to create structures down to 100s of nanometers that still show luminescence

Methods

Results

Conclusion