Towards Unveiling the Exact Molecular Structure of Amorphous Red Phosphorus by Single-molecule Studies
Song Zhang,a,+ Hu‐jun Qian,b,+ Zhonghua Liu,c Hongyu Ju,a Zhong‐yuan Lu,b Haiming Zhang,c Lifeng Chi,c,* Shuxun Cuia,*
a Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China
b State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
c Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, China
Since the discovery of amorphous red phosphorus (a‐red P) in 1847, a number of possible structures of a-red P have been proposed. However, the exact molecular structure of a-red P is not determined yet due to the amorphous nature. Here in this study, we utilize several methods to investigate some basic properties of a-red P, which are helpful to determine the structure. The experimental results from scanning tunneling microscopy (STM) and gel permeation chromatography (GPC) confirm that a‐red P is a linear inorganic polymer with a broad molecular weight distribution. The theoretical single‐molecule elasticities of the possible a‐red P structures are obtained by quantum mechanical (QM) calculations. It is found that the experimental single‐molecule elasticity of a‐red P measured by single‐molecule AFM matches with the theoretical result of the zig‐zag ladder structure, indicating that a‐red P may adopt this structure. Although this conclusion needs further validation in the future, this fundamental study represents a helpful attempt to solve the long-lasting riddle of red phosphorus. It is expected that the strategy utilized in this work can be applied to study other inorganic polymers.