Molecularly Engineered Black Phosphorus Heterostructures with Improved Ambient Stability and Enhanced Charge Carrier Mobility

Abstract

Overcoming the intrinsic instability and preserving unique electronic properties are key challenges for the practical applications of black phosphorus (BP) under ambient conditions. Here, it is demonstrated that molecular heterostructures of BP and hexaazatriphenylene derivatives (BP/HATs) enable improved environmental stability and charge transport properties. The strong interfacial coupling and charge transfer between the HATs and the BP lattice decrease the surface electron density and protect BP sheets from oxidation, resulting in an excellent ambient lifetime of up to 21 d. Importantly, HATs increase the charge scattering time of BP, contributing to an improved carrier mobility of 97 cm2 V‐1 s‐1, almost three times of the pristine BP films, based on noninvasive THz spectroscopic studies. The film mobility is an order of magnitude larger than previously reported values in exfoliated 2D materials. The strategy opens up new avenues for versatile applications of BP sheets and provides an effective method for tuning the physicochemical properties of other air‐sensitive 2D semiconductors.

Module‐Patterned Polymerization towards Crystalline 2D sp2‐Carbon Covalent Organic Framework Semiconductors

“…The enhanced charge carrier mobilities upon iodine doping can be traced to the increased scattering times, which may be due to passivation effect of iodine treatment. This reduces the momentum scattering by defects, and thus increases the charge carrier mobility [15] . Noticeably, the mobility of I 2 ‐sp 2 c‐COF is close to the mobility of 86.8 cm 2 V −1 s −1 predicted theoretically [16] …”

Scalable Van der Waals Encapsulation by Inorganic Molecular Crystals

“…[20,24] The van der Waals (vdW) encapsulation, which is nondestructive to 2D materials, turns out to be the most promising encapsulation approach. [25][26][27] Some efforts have been paid in this strategy, such as solvent stabilization in liquid exfoliation, [28][29][30] transferring robust 2D materials (graphene or h-BN. [31][32][33][34][35] ), or depositing organic layers.…”

Improving Harsh Environmental Stability of Few‐Layer Black Phosphorus by Local Charge Transfer

“…[32,33] In Figure 2e, the interplanar spacing of 0.266 nm can be ascribed to the (111) plane of BP crystals. [27] The SAED pattern of Au/FL-BP (Figure 2f) illustrates two sets of parallel diffraction spots. The (111) and (220) planes of BP crystals with distance of 0.266 and 0.186 nm are well parallel with the (111) and (220) planes of Au nanoparticles (fcc phase) with the distance of 0.235 and 0.144 nm, respectively.…”

“…The charge transport of Au/FL-BP FETs has no reduction after annealing at 573 K for 3, 6, and 9 h, including the parameters of mobility (µ), the ON-OFF ratio, and the saturation current (I ds max ). The photodetection performance of Au/FL-BP FET displays no degradation of photocurrent (I ds ), rise time (τ rise ), decay time (τ decay ), S2 (Supporting Information), indicates that the high reliability of our EI&ED method for preparing scalable, harsh environment stable FL-BP crystals, [14,16,17,27,[38][39][40][41][42][43] promising the implementation of FL-BP based terminal devices industrialization.…”

“…Doping of BP with certain elements can also improve its stability in bulk materials. [18] In contrast, the fabrication of charge transfer complexes between FL-BP and appendants such as metal ions (Ag + and Co 2+ ), [19][20][21][22] positive polymers, and organic molecules, [23][24][25][26][27][28] has shown competitive advantage to passivate FL-BP in large scale. The mechanism is that the lone-pair electrons in P atoms can be partially shifted to electron acceptor via the electrostatic interaction, and FL-BP ends up with a reduced reactivity.…”