Construction of Infrared Photosensitive Energetic Materials Based on π-π Conjugation

Lasers typically exhibit many advantages over conventional light sources, including the ability to produce monochromatic laser beams, small divergence angles, excellent coherence, and high output power. Therefore, investigating the application of laser ignition/initiation properties in the field of energetic materials is of great significance. In this study, two energetic coordination compounds (ECCs) were successfully synthesized: [Pb(Az-BTz)(H₂O)₃]_n, referred to as ECC-1 in this work, and [Pb(Az-BTz)(NO₃)(H₂O)₂]_n, referred to as ECC-2, where Az-BTz denotes 1,2-di(2'H-[1,5'-bitetrazol]-5-yl)diazene. Although ECC-1 shows a more pronounced red-shifted light absorption than ECC-2 does due to π-π stacking and charge transfer effects, it ultimately underperforms in practical applications because it fails to cover the widely adopted 808 nm band. By contrast, band structure calculation results indicate that ECC-2 features a narrower energy band gap, which significantly improves its light-to-heat conversion efficiency. Despite ECC-2 exhibiting relatively lower thermal stability than ECC-1─thus making it more susceptible to thermal initiation─this drawback is offset by its superior overall performance. Ultimately, laser initiation experiments further confirm the effectiveness of ECC-2, which demonstrates an impressive initiation time of 1.02 ms and an initiation energy below 5 mJ.