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The internal energy released by the fuel-oxidizer reaction in combustion sol-gel enables the precursor to be thermally converted at a much lower temperature compared to conventional metal oxide chemistries. Conversion to metal oxide using deep ultraviolet (DUV) light has been reported. While it is logical to assume that the requirement for thermal and radiant energy would be correlated, the relationship between thermal and DUV conversion has not been studied. In this work, indium(III) nitrate precursor formulations with various fuels—different concentrations of acetylacetone (AcAc), indium acetylacetone, acetic acid, and urea—are investigated. We demonstrate that the choice of fuel has a significant impact on the thermal decomposition temperature (Td) of the indium(III) nitrate precursor, as determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). We further test the hypothesis that fuel selection influences the DUV photosensitivity in accordance with their Td. Our results show no clear correlation between Td and DUV photosensitivity. These results are explained by performing Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) to understand the chemical composition of the films as they undergo DUV exposure. Atomic force microscopy (AFM) images reveal that these films are smooth, except for nanoscale protrusions present on some films. Finally, energy-dispersive X-ray spectroscopy (EDX) shows no loss of indium during the DUV conversion, regardless of the fuel used. This study highlights the limitations of extrapolating thermal results to combustion sol-gel conversion using other energy sources. 

Article“Green” Fabrication of High-performance Transparent Conducting Electrodes by Blade Coating and Photonic Curing on PET for Perovskite Solar CellsJustin C. Bonner 1,†, Robert T. Piper 1,†, Bishal Bhandari 2, Cody R. Allen 2, Cynthia T. Bowers 3,4, Melinda A. Ostendorf 3,4, Matthew Davis 5, Marisol Valdez 6, Mark Lee 2 and Julia W. P. Hsu 1,∗1 Department of Materials Science and Engineering, University of Texas at Dallas, 800 W Campbell Road, RL-10, Richardson, TX 75080, USA2 Department of Physics, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA3 Materials Characterization Facility at the Air Force Research Laboratory, 2941 Hobson Way, WPAFB, OH 45433, USA4 UES, Inc., a BlueHalo Company, 4401 Dayton-Xenia Rd, Dayton, OH 45432, USA5 Energy Materials Corporation, 1999 Lake Ave B82 Ste B304, Rochester, NY 14650, USA6 Department of Chemistry, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA* Correspondence: jwhsu@utdallas.edu† These authors contributed equally to this work.Received: 30 September 2024; Revised: 25 October 2024; Accepted: 30 October 2024; Published: 5 November 2024Abstract: This study presents an innovative material processing approach to fabricate transparent conducting electrodes (TCEs) on polyethylene terephthalate (PET) substrates using blade coating and photonic curing. The hybrid TCEs consist of a multiscale Ag network, combining silver metal bus lines and nanowires, overcoated by an indium zinc oxide layer, and then photonically cured. Blade coating ensures film uniformity and thickness control over large areas. Photonic curing, a non-thermal processing method with significantly lower carbon emissions, enhances the conductivity and transparency of the coated layers. Our hybrid TCEs achieve an average transmittance of (81 ± 0.4)% referenced to air ((90 ± 0.4)% referenced to the PET substrate) in the visible range, an average sheet resistance of (11 ± 0.5) Ω sq−1, and an average surface roughness of (4.3 ± 0.4) nm. We benchmark these values against commercial PET/TCE substrates. Mechanical durability tests demonstrate <3% change in resistance after 2000 bending cycles at a 1 in radius. The scalable potential of the hybrid TCE fabrication method is demonstrated by high uniformity and excellent properties in 7 in × 8 in large-area samples and by performing the photonic curing process at 11 m min−1. Furthermore, halide perovskite solar cells fabricated on these hybrid TCEs achieve average and champion power conversion efficiencies of (10.5 ± 1.0) % and 12.2%, respectively, and significantly outperform devices made on commercial PET/TCEs. This work showcases our approach as a viable pathway for high-speed “green” manufacturing of high-performance TCEs on PET substrates for flexible optoelectronic devices.