Covalent Functionalization of Black Phosphorus with Conjugated Polymer for Information Storage

Abstract

Major disadvantages of blackphosphorus (BP) are its poor air-stability and poor solubility in common organic solvents.T he best wayt os olve this problem is to incorporate BP into ap olymer backbone or ap olymer matrix to form novel functional materials that can provide both challenges and opportunities for new innovationi no ptoelectronic and photonic applications.A sap roof-of concept application, we synthesized in situ the first highly soluble conjugated polymercovalently functionalizedB Pd erivative (PDDF-g-BP) which was used to fabricate ar esistive random access memory (RRAM) device with aconfiguration of Au/PDDF-g-BP/ITO. In contrast to PDDF without memory effect, PDDF-g-BPbased device exhibits anonvolatile rewritable memory performance,w ith at urn-on and turn-off voltages of + 1.95 Va nd À2.34 V, and an ON/OFF current ratio of 10 4 .T he current through the device in both the ON and OFF states is still kept unchanged even at 200th switching cycle.T he PDDF/BP blends show avery unstable memory performance with avery small ON/OFF current ratio.Asanovel two-dimensional layered material found in the post-graphene age,f ew-layer black phosphorus (BP) has found many potential applications in the fields of field-effect transistors,o ptical modulators,m ode-locked and Q-switched lasers,o ptical limiters,a nd others due to its unique and superior properties such as higher charge-carrier mobility (ca. 10 3 cm 2 V À1 S À1 ), thickness-depended and tunable direct band gap (0.3-1.5 eV), strong intrinsic in-plane anisotropy,a nd broadband nonlinear optical response. [1][2][3][4][5][6][7][8][9][10] Similar to C 60 , carbon nanotubes and graphene,B Ph as also very poor solubility in common organic solvents,l eading to great difficulty in fabricating BP-based thin film devices by using solution-processable techniques.M ore importantly,B Pw ill degrade rapidly in the presence of oxygen and moisture within the scope of hours.T oi mprove the environmental stability of few-layer BP,anumber of essential strategies, including encapsulation, [11] non-covalent functionalization, [12,13] covalent chemical modification [14] and high boiling solvent exfoliation, [15] have been employed to suppress the chemical degradation of exfoliated BP.It has been recognized that design and preparation of BPbased soluble organic/polymeric functional materials are ak ey issue for exploring more applications of BP,w hich would most likely be driven by breakthroughs in chemistry of BP that combine the economy of scale with function in near future.Ryder et al. are the first to report the organic chemical modification of few-layer BP,w hich was prepared by mechanically exfoliating bulk BP on Si/SiO 2 substrates,w ith 4-nitrobenzene-diazonium (4-NBD) and 4-methoxybenzenediazonium (4-MBD) tetrafluoroborate salts. [14] However,t he resultant material could not be directly used for fabrication of electronic devices by using traditional spin-coating technique due to its poorer solubility in organic solvents.Inthis work, by using 4-bromobenzene-diazonium( ...

Covalent functionalization of two-dimensional black phosphorus nanosheets with porphyrins and their photophysical characterization

“…The similar peaks were observed in the BPNSs-TPP along with clear vibrational signals corresponding to the fingerprint region of porphyrin molecules and a weak absorption at 870 cm -1 due to the P-C stretching vibration. 42,54 The presence of additional Please do not adjust margins Please do not adjust margins peaks in the BPNSs-TPP compared to the bare BPNSs and the P-C stretching further confirm the successful covalent modification of BPNSs with TPP. Morphology of exfoliated and functionalized BPNSs were studied using transmission electron microscopy (TEM) and high resolution TEM (HR-TEM).…”

“…In this context, hybrid materials of BPNSs with multifunctional properties are very few and are not well exploited. [41][42][43] Porphyrins are well known functional dyes with extraordinary physicochemical properties holding versatile applications in photomedicines, photovoltaic and optoelectronic devices. [44][45][46][47] Porphyrins have been chemically attached onto various nanomaterials including carbon nanotubes, graphene and MoS 2 to achieve novel functional hybrid materials.…”

“…. The P2p core-level XPS spectrum of BPNSs could be fitted to four peaks at 129.78, 130.61, 133.38 and 134.30 eV, assigned to P2p 3/2 , P2p 1/2 , P-O and P=O functionalities 42,53. After covalent functionalization of BPNSs with TPP, the P2p core level XPS spectrum showed five peaks centered at 129.90, 130.72, 131.16, 133.27 and 134.33 eV, respectively.…”

Recent Advances in Chemical Functionalization of 2D Black Phosphorous Nanosheets

“…In order to overcome the poor air stability and improve dispersibility of BPNSs, Chen and co‐workers synthesized a conjugated polymer derivative modified BPNSs, poly[(1,4‐diethynylbenzene)‐alt‐9,9‐bis(4‐diphenylaminophenyl)fluorene] (PDDF)‐covalently grafted BP (PDDF‐ g ‐BP), by using 4‐bromobenzene‐diazonium (4‐BBD) functionalized BP (4‐BBD–BP) ( Figure ) . Initially, BPNSs with an average thickness of 10.4 nm were prepared by liquid phase exfoliation in NMP and then the 4‐BBD moieties were covalently attached to the BPNSs surface using diazonium chemistry.…”

“…a) Pd[(PPh 3 ) 4 ], CuI, Et 3 N, dry acetonitrile, 80 °C, 72 h. b) N ‐methyl‐2‐pyrrolidone (NMP), ultrasonic radiation for 6 h (200 W). c) 4‐Bromobenzenediazonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, acetonitrile, room temperature (RT), 3 h. d) 1,4‐Diethynyl benzene, 9,9‐bis(4‐diphenylaminophenyl)‐2,7‐dibromofluorene, Pd[(PPh 3 ) 4 ], CuI, Et 3 N, dry acetonitrile, 80 °C, 72 h. Reproduced with permission . Copyright 2018, John Wiley and Sons.…”