Structure-Induced Energetic Coordination Compounds as Additives for Laser Initiation Primary Explosives

Laser ignition of primary explosives presents more reliable alternative to traditional electrical initiation methods. However, the commercial initiator lead azide (LA) requires a high-power density laser to detonate, with the minimum laser initiation energy (E_min) of 2402 mJ. Currently, the laser-ignitable metal complex-based igniters still suffer from weak detonation capabilities and high E_min values. Here, the approach is first proposed to design laser ignition primary explosives within the high energy azide and tetrazole-based energetic coordination compounds (ECCs), [Co(N₃)(2-bmttz)(H₂O)]₂ 1 and [Co(N₃)(2-bmttz)(MeOH)]₂ 2 as additives to LA. Material 1e with 4 wt.% of 1 in LA, exhibits ultra-low laser initiation threshold (E_min = 1.6 mJ) and ultrafast corresponding time (T_min = 0.2 ms). Specially, compared to LA, the threshold of 1e is as low as 1/1500 of that of LA. Moreover, 30 mg 1e successfully detonates RDX with a laser energy of 1.6 mJ. Theoretical calculations and experiment results reveal that 1 exhibits the superior additive effect compared to 2, attributed to its more enhanced ability to generate free radicals and higher photothermal conversion efficiency under laser conditions. This work represents a paradigm shift, with the potential to develop a laser-driven micro-detonator combining powerful detonation capabilities with exceptionally low laser initiation energy.