Noncovalent Functionalization and Passivation of Black Phosphorus with Optimized Perylene Diimides for Hybrid Field Effect Transistors

Abstract

years due to its outstanding physical and chemical properties. [1-2] Experimental studies have shown that BP-based field effect transistors (FETs) exhibit ambipolar electron/hole behavior while possessing advanced values in terms of the on/off ratio (10 6) and high carrier mobility (up to ≈1000 cm 2 V −1 s −1). Moreover, the tuneable direct bandgap of the material (spanning from 0.3 eV in bulk to 2 eV for a monolayer) make it an excellent candidate for (opto)electronics. [1-8] Besides, its puckered structure with the free pair of electrons and its large chemically active surface area positions it as an excellent material in applications beyond electronics like gas sensing [9-13] and organic catalysis, among others. [14-15] Nevertheless, the biggest handicap of BP is its high oxophilicity, which turns its surface hydrophilic, promoting its decomposition to phosphoric acid species in presence of O 2 and H 2 O. [16-19] Furthermore, it has been proven that the degradation of the material can be enhanced by photo-oxidation, due to the formation of highly reactive oxygen radicals. [20-22] Therefore, a large part of the research effort on BP is focused on alleviating its degradation in environmental conditions, avoiding oxidation and, consequently, facilitating its Amongst the different existing methods to passivate black phosphorus (BP) from environmental degradation, the noncovalent functionalization with perylene diimides (PDI) has been postulated as one of the most promising routes because it allows preserving its electronic properties. This work describes the noncovalent functionalization and outstanding environmental protection of BP with tailor made PDI having peri-amide aromatic side chains, which include phenyl and naphthyl groups, exhibiting a significantly increased molecule-BP interaction. These results are rationalized by density functional theory (DFT) calculations showing that the adsorption energies are mainly governed by van der Waals (vdW) interactions and increase concomitantly with the aromatic character of the side chains. The resulting hybrids are thoroughly characterized showing enhanced ambient and thermal stabilities. Last but not least, hybrid organic-inorganic BP-PDI field effect transistors (FETs) are studied for the first time showing the usefulness of PDI derivatives as efficient passivation layers while obtaining improved values of electron mobilities. These results pave the way for the use of optimized PDIs by molecular engineering to preserve the electronic properties of BP FETs, using straightforward wet chemical approaches.

Chemical Functionalization of 2D Black Phosphorus toward Its Applications in Energy Devices and Catalysis: A Review

“…Later, the same research group performed noncovalent functionalization of BPNSs with tailor‐made PDI bearing periamide aromatic side chains, which include phenyl and naphthyl groups. [ 93 ] The presence of tailored aromatic groups led to increased adsorption of PDI moieties to the surface of BP sheets, which was confirmed by DFT calculations and Raman spectroscopy studies. XPS, temperature‐dependent Raman spectroscopy, and thermal gravimetric mass spectrometry (TG‐MS) experiments revealed increased ambient stability of functionalized materials.…”

Covalent and non-covalent chemistry of 2D black phosphorus

“…Conceptually, this can be achieved by allowing the external molecules to bind the surface via non-covalent stacking interactions. 53,54 Since BP exposes lone pairs to the surface it is reasonable to assume that it will strongly interact with electron acceptors. Indeed, we demonstrated for the rst time that the treatment with electron-poor and polarizable polycyclic aromatic molecules provides considerable stabilization of exfoliated BP nanosheets.…”

“…In order to force the PDI peripheral moieties interact stronger with the surface of BP we have recently designed two PDI derivatives with increased number of p electrons as aromatic end-groups (namely benzene and naphthalene). 54 This strategy signicantly improved surface coating, allowing for a denser and more structured packing of the molecules thus increasing environmental and thermal stabilities of BP, as demonstrated by XPS, temperature-dependent Raman spectroscopy and TG-MS. Electronic properties of these hybrids were studied for the rst time by constructing PDI-BP eld effect transistors (FETs) showing a hysteretic charge balance behaviour where preservation of the electronic properties of BP is reected in the values of charge carrier mobilities comprised in the 130-140 cm 2 V À1 s À1 range. Similar strong non-covalent interactions were involved in the formation of adducts of BP with organoboron derivatives of a conjugated pyrene 55 and 1-pyrenebutyric acid.…”

A Novel Enzyme‐Free Biosensor for Hydrogen Peroxide Based on Black Phosphorus @Au‐Ag Nanohybrids

“…Electrochemical sensors are based on advanced nanomaterials [11] . Black phosphorus (BP) as a rising‐star two‐dimensional nanomaterial with high carrier mobility, tunable direct bandgap, and excellent in‐plane anisotropy, [12] has gained remarkable interest in the application of field‐effect transistors, [13] lithium‐and sodium‐ion batteries, [14] photovoltaics, [15] and gas sensors [16] . Due to its low cytotoxicity and good biocompatibility, black phosphorus is also regarded as a promising candidate for biosensor and biomedical sensors [17] .…”