Universal Transfer Printing of Micelle-Templated Nanoparticles Using Plasma-Functionalized Graphene

Abstract

Nanostructure incorporation into devices plays a key role in improving performance, yet processes for preparing two-dimensional (2D) arrays of colloidal nanoparticles tend not to be universally applicable, particularly for soft and oxygen-sensitive substrates for organic and perovskite-based electronics. Here, we show a method of transferring reverse micelle-deposited (RMD) nanoparticles (perovskite and metal oxide) on top of an organic layer, using a functionalized graphene carrier layer for transfer printing. As the technique can be applied universally to RMD nanoparticles, we used magnetic (γ-Fe 2 O 3 ) and luminescent (methylammonium lead bromide (MAPbBr 3 )) nanoparticles to validate the transfer-printing methodology. The strong photoluminescence from the MAPbBr 3 under UV illumination and high intrinsic field of the γ-Fe 2 O 3 as measured by magnetic force microscopy (MFM), coupled with Raman measurements of the graphene layer, confirm that all components survive the transfer-printing process with little loss of properties. Such an approach to introducing uniform 2D arrays of nanoparticles onto sensitive substrates opens up new avenues to tune the device interfacial properties.

Unusual Phase Behaviour for Organo-Halide Perovskite Nanoparticles Synthesized via Reverse Micelle Templating

“…As the reaction region to form the nanoparticles is limited to the spaces within the micelles, size-tunable nanoparticles with PDIs around 0.10 are easily achieved [10,26,53,54]. Such values are within the range of monodispersity [55,56], which is a key metric for the widescale application of nanoparticle-based devices [57].…”

Enhanced Stokes Shift and Phase Stability by Cosynthesizing Perovskite Nanoparticles (MAPbI3/MAPbBr3) in a Single Solution

“…[13] Typically for NP synthesis and size control, high-molecularweight polymers are chosen that form dense-core micelles, where the corona offers tight shielding against the environment. [20,37,38] Using lower-molecular-weight polymers results in the formation of a larger ballooning micelle structure with a looser corona of shorter PS chains, allowing easier infiltration of precursor salts [37] (see Figure S1, Supporting Information). However, the downside of such a micellar structure is lowered protection from hydration, as proven by Arbi et al, in the case of polymorphic iron oxide phase formation using different PS-b-P2VP diblock copolymer micelles.…”

Role of hydration and micellar shielding in tuning the structure of single crystalline iron oxide nanoparticles for designer applications

“…[27] Synthesized nanoparticles optimized for use in organic solar cells were transfer-printed using graphene onto P3HT:PCBM to control the injection of charge carriers. [52] The high temperature stability of micelle templated nanoparticles was exploited to form a 𝛾-Fe 2 O 3 nanoparticle/𝛼-Fe 2 O 3 heterojunction electrocatalyst to improve charge separation, yielding higher water splitting efficiency. [6] A deep understanding of the formation and conversion processes allows the reverse micelle templating approach to be effectively utilized to tailor nanoparticles for specific applications.…”

“…[43] Moreover, these nanoparticles can be transfer-printed on to substrates that may be sensitive to direct processing. [52] In this contribution, we use the chemical fingerprints from Raman spectroscopy to explore the impact of modifying the growth conditions and post-deposition treatments on the formation of iron oxide nanoparticles. The shielding environment of the micelles was seen to prevent the formation of a hydrated phase that can directly convert to the thermodynamically stable 𝛼-Fe 2 O 3 at low temperatures.…”