Near-Infrared Light Triggered a High Temperature Utilizing Donor-Acceptor Cocrystals

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Current laser initiation systems for energetic materials are expensive and bulky.
• There is a need for compact, lightweight, and cost-effective initiation methods.

Purpose of the Study:

• To develop a suitable initiation system for energetic materials using low-power near-infrared lasers.
• To investigate the properties of molecularly tailored donor-acceptor (D-A) charge-transfer (CT) cocrystals for laser initiation.

Main Methods:

• Synthesized 1:1 donor-acceptor (D-A) charge-transfer (CT) cocrystals using N,N,N',N'-tetramethyl-p-phenylenediamine and tetrahalo-1,4-benzoquinones (TMPD-TXBQ).
• Characterized the cocrystals' absorption properties and self-assembly behavior.
• Irradiated TMPD-TXBQ cocrystals with a low-power 808 nm laser to assess photothermal conversion and thermal polymerization.

Main Results:

• TMPD-TXBQ cocrystals exhibited ultrabroad absorption (200-2500 nm) and fast self-assembly.
• The narrow highest occupied molecular orbital-lowest unoccupied molecular orbital gap facilitated efficient near-infrared light harvesting.
• Low-power laser irradiation (40 mJ, 260 mW·cm⁻²) induced efficient photothermal conversion and exothermic thermal polymerization, reaching 318.9 °C.

Conclusions:

• TMPD-TXBQ cocrystals demonstrate potential as compact, lightweight, and cost-effective near-infrared laser initiators.
• The high temperatures achieved are sufficient for initiating most common energetic materials.
• This D-A cocrystal system offers a promising advancement in laser-based initiation technologies.