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.