Chloro-substituted metallo-phthalocyanines (TiPcCl₂, MnPcCl, InPcCl, AlPcCl) applied to organic devices

Chlorinated phthalocyanines—TiPcCl₂, MnPcCl, InPcCl, and AlPcCl—were studied as organic semiconductors and, in this framework, their behavior as a buffer layer. Initially, these metallophthalocyanines were characterized in solution using UV–visible spectroscopy to determine their optical band gaps, with results compared to density functional theory (DFT) calculations. The phthalocyanines were subsequently deposited as films via high-vacuum sublimation, and optically characterized to assess their reflectance and band gaps using the Kubelka-Munk function, with the lowest band gap for MnPcCl of 1.67 eV. Morphological and mechanical characterization revealed the Knoop hardness in the range of 10–15 HK for all films, and a tensile strength highest for the InPcCl film, of 9.3x10⁻³ Pa. Fluorescence analysis revealed peak emission around 438 nm, corresponding to blue light. Among the compounds, InPcCl exhibited the highest emission intensity, followed by TiPcCl₂, AlPcCl, and MnPcCl. The metal at the center of chlorinated phthalocyanines was found to exert a determining effect on the properties of semiconductor films. Finally, single-layer devices were fabricated and examined under various illumination conditions to analyze their current-voltage (I-V) and power-voltage (P-V) characteristics and their electrical conductivity across different temperatures. The highest power obtained in the devices was 2.78 mW, while the highest electrical conductivity was 6.6x10⁻² S/cm, which suggests the potential employment of these films for use in organic optoelectronics as semiconductors and buffer layers.