Recent Progress on Stability and Passivation of Black Phosphorus

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Chemistry

Background:

• Black phosphorus (BP) is a 2D material with exceptional in-plane anisotropic electronic, optical, and vibrational properties, including a tunable band gap.
• The practical application of BP is severely hindered by its surface instability and rapid chemical degradation in ambient conditions, particularly in air.
• Previous research was significantly constrained by the susceptibility of black phosphorus surfaces to environmental degradation.

Purpose of the Study:

• To review the fundamental chemistry governing black phosphorus degradation.
• To highlight recent progress and robust strategies developed to mitigate BP surface degradation.
• To analyze the impact of degradation and passivation methods on BP's intrinsic anisotropic surface properties.

Main Methods:

• Comprehensive review of existing literature on black phosphorus degradation chemistry.
• Analysis of various passivation strategies employed to protect black phosphorus surfaces.
• Comparison of device performance between encapsulated and non-encapsulated black phosphorus.
• Examination of anisotropic photophysical surface properties, including excitons, surface plasmons/phonons, and topological/Dirac states.

Main Results:

• Significant advancements have been made in developing strategies to stabilize black phosphorus surfaces against ambient degradation.
• Encapsulation techniques have shown promise in preserving the performance of black phosphorus devices compared to non-encapsulated counterparts.
• Both environmental degradation and passivation methods can substantially alter the sensitive anisotropic surface properties of black phosphorus.

Conclusions:

• Novel strategies now enable researchers to overcome the instability issues of black phosphorus, paving the way for its technological applications.
• Understanding the interplay between degradation, passivation, and intrinsic surface properties is crucial for harnessing black phosphorus's full potential.
• Further research is needed to fully characterize and control the modifications of BP's unique surface states under various environmental conditions.