Confined-Plume Chemical Deposition: Rapid Synthesis of Crystalline Coatings of Known Hard or Superhard Materials on Inorganic or Organic Supports by Resonant IR Decomposition of Molecular Precursors

Abstract

A one-step process for preparing microcrystalline coatings of known superhard, very hard, or ultraincompressible ceramic compositions on either inorganic or organic supports is reported. Midinfrared pulsed-laser irradiation of preceramic chemical precursors layered between IR-transmissive hard/soft supports under temporal and spatial confinement at a laser wavelength resonant with a precursor vibrational band gives one-step deposition of crystalline ceramic coatings without incurring noticeable collateral thermal damage to the support material. Reaction plume formation at the precursor/laser beam interface initiates confined-plume, chemical deposition (CPCD) of crystalline ceramic product. Continuous ceramic coatings are produced by rastering the laser beam over a sample specimen. CPCD processing of the Re-B single-source precursor, (B(3)H(8))Re(CO)(4), the dual-source mixtures, Ru(3)(CO)(12)/B(10)H(14) or W(CO)(6)/B(10)H(14), and the boron/carbon single-source precursor, o-B(10)C(2)H(12), confined between Si wafer or NaCl plates gives microcrystalline deposits of ReB(2), RuB(2), WB(4), or B(4)C, respectively. CPCD processing of Kevlar fabric wetted by (B(3)H(8))Re(CO)(4) produces an oriented, microcrystalline coating of ReB(2) on the Kevlar fabric without incurring noticeable thermal damage of the polymer support. Similarly, microcrystalline coatings of ReB(2) can be formed on IR-transmissive IR2, Teflon, or Ultralene polymer films.

Construction of a Semiconductor–Biological Interface for Solar Energy Conversion: p-Doped Silicon/Photosystem I/Zinc Oxide

“…Therefore, we employed a relatively new technique, CPCD, that has been used previously to rapidly deposit crystalline ReB 2 , RuB 2 , WB 4 , and B 4 C on various substrates without collateral thermal damage. 14 In CPCD (Figure 2), the irradiation of appropriate molecular precursors spatially confined between two support plates by a beam of pulsed infrared (IR) laser light leads to rapid precursor decomposition, the formation of a visible reaction plume under spatial and temporal confinement, and the deposition of crystalline ceramic material of high purity as the laser beam is rastered across the specimen. Pulse energy analysis reveals that 75−95% of the IR light energy is absorbed during precursor decomposition, thus permitting the use of either hard or soft support materials.…”

“…CPCD was performed following the same concept described by Ivanov and co-workers . Here, the ZnO precursor, Zn 5 (CO 3 ) 2 (OH) 6 (hydrozincite), was synthesized by a method similar to that of Wahab and co-workers .…”

“…CPCD was performed following the same concept described by Ivanov and co-workers. 14 Here, the ZnO precursor, Zn 5 (CO 3 ) 2 (OH) 6 (hydrozincite), was synthesized by a method similar to that of Wahab and co-workers. 23 Hydrozincite was suspended in benzene (10 mM) and drop cast onto the PSI-modified silicon electrode (10 μL).…”

“…In other words, one of the semiconductors will need to be deposited under mild conditions. We address this issue by employing a relatively new deposition technique known as confined-plume chemical deposition (CPCD) to fabricate PSI/ZnO bilayers which exhibit good electrical contact . These bilayers were then incorporated into a functional p-doped silicon/PSI/ZnO/ITO solid-state photovoltaic device.…”

Nucleophilic Substitution Reactions in the [B3H8]− Anion in the Presence of Lewis Acids

“…The high content of hydrogen [ 11 ] in some adducts determines their use as chemical accumulators of hydrogen [ 7 , 12 , 13 ]. In addition, substituted derivatives of the octahydrotriborate anion can act as ligands in complexes of transition metals [ 14 , 15 , 16 ], which does not exclude their use in the preparation of boride coatings [ 17 , 18 ], as was previously shown for some complexes of the octahydrotriborate anion [ 19 , 20 ]. Substituted [B 3 H 8 ] − derivatives can also be considered as precursors to substituted higher boron clusters (e.g., B 5 H 9 , B 4 H 10 ).…”