CO2 Laser Sintering of TiO2 Nanoparticles Thin Films for Improved Transmittance

CO2 laser additive manufacturing of multi-layer heterogeneous transparent films using TiO2 and SiO2 nanoparticles

“…% TiO2 and 1 𝑤𝑡. % SiO2 nanosuspensions 22 . These chemicals were purchased from US Research Nanomaterials, Inc. 1 𝑤𝑡.…”

“…13(b), XRD patterns of QS/TiO2/TiO2/TiO2 film shows several crystallin peaks corresponding to the crystalline planes of (101), ( 112), ( 200), ( 105), (211), and (213) localized at 2𝜃 = 25°, 37°, 48°, 53°, 55°, and 62°, respectively. These peaks are correlated to the anatase crystalline phase of TiO2 with a space group 𝐼4 1 /𝑎𝑚𝑑 (JCPDS78-2486) 8,10,22 . The heterogeneous QS/TiO2/SiO2/TiO2 and QS/SiO2/TiO2/SiO2 films show a few anatase peaks with low intensities, this is caused by the presence of TiO2 with SiO2 layer (Fig.…”

“…The temperature required to evaporate EG and subsequently sinter nanoparticles is estimated to be the temperatures at the laser-material interaction zone on the surface of the sample 10 . A heat conduction model was previously developed to predict the temperature as a function of the selected laser processing parameters 11,22 . It was reported 12 that the sintering temperature to prepare transparent SiO2 films is around 500°𝐶 − 544°𝐶.…”

“…L. Ye et al 30 demonstrated that the deposition of a highly transparent SiO2 film can be achieved at 500°𝐶. The processing parameters used in our study were also selected according to the effect of heating and cooling rates on the deposited films on quartz substrates, as we previously reported in 11,22 . The wet film of thickness 𝑑 𝑆𝐶 is evaporated at 0.85 − 1 𝑊 (𝑇 = 185 °𝐶) to dry/evaporate EG and then heated at 2 − 2.3 𝑊 (𝑇 = 350 °𝐶 − 400 °𝐶 for TiO2 and 544°𝐶 for SiO2) to accomplish sintering of NPs to form transparent films of a final thickness 𝑑 𝑆𝐼 (where 𝑑 𝑆𝐼 < 𝑑 𝑆𝐶 ).…”

“…Different techniques; for example, sol-gel spin-coating 5,6 , spray deposition 16 , and chemical vapor deposition 17 , followed by the sintering process in a furnace can be used to deposit transparent TiO2/SiO2 films. Among these method and complex laser printing techniques [18][19][20][21] , spin-coating wet deposition followed by laser sintering is suitable for depositing highly uniform and transparent thin films of NPs 22 . Also, laser processing (or sintering) allows localized heating at high temperatures without heating the entire substrate, whereas the entire substrate can be heated in the case of sintering in a furnace.…”