Synthesis, Crystal Structures, and Nonlinear Optical Properties of Chalcone Doped by Titanium Dioxide Nanoparticles for Solar Cell Application

Abstract

In this work, we investigate the effects of titanium dioxide (TiO2) nanoparticle percentages on the optical and electrical properties of 3-(4-(dimethyl-amino)phenyl)-1-phenyl-(2E)-propen-1-one (DAAP). In order to achieve thin films, DAAP was dissolved in acetone and doped with different ratios of TiO2. The pure and composite mixtures were spin-coated onto a glass substrate. We investigated the influence of TiO2 on XRD patterns, absorption, energy band gaps, refractive indices, sheet resistance, resistivity, and Hall coefficients. We used the XRD technique to study the structure of DAAP pre- and post-doping with TiO2 nanoparticles. It was evident from the XRD patterns that the composite transformed from an amorphous to a polycrystalline nature and behaved similarly to titanium oxide crystals. The pure sample exhibited an absorption band of 409 nm. With the addition of TiO2, the whole absorption spectrum shifted to the blue region. For example, with a dopant percentage of 15%, the spectrum shifted to a wavelength of 368 nm. The energy band gap values increased with a dopant concentration from 2.65 eV of pure DAAP to 2.91 eV of maximum dopant percentage (15%). The refractive index decreased to its lowest value of 2.47 with the increase in TiO2 concentration. The impact of increasing TiO2 percentage highly improved electrical characteristics by reducing the sheet resistance and resistivity to 905 k(Ω/sq) and 230 k on the (Ω · cm), respectively. An optimized DAAP doped with 15% TiO2 has been used as an n-type layer on a p-type monocrystalline silicon wafer (Si (111)) to fabricate η = 0.23% efficient solar cells. On the other hand, the amplified spontaneous emission (ASE) of the DAAP and dopant mixture was excited by the third harmonic generation (λex = 355 nm). The pure DAAP exhibits an ASE peak at 535 nm. The intensity decreased rapidly with increased dopant concentration, whereas the full width at half-maximum (FWHM) increased slightly.