Fabrication of Hybrid Photovoltaic Cell Using Atomic Layer Deposited TiO₂ Thin Film on CuPc Layer

In this work, light-to-current conversion efficiency of a solar cell having the device structure of indium tin oxide (ITO) anode/copper phthalocyanine (CuPc, 50 nm)/titanium dioxide (TiO₂) (80 nm)/aluminum (Al) (150 nm) electrode is reported. The TiO₂ layer was fabricated by atomic layer deposition (ALD) method onto the CuPc layer. The light-to-current conversion efficiency of the photovoltaic (PV) cell was found to be 3.7 × 10⁻⁴% with the fill factor 0.14. The analysis of atomic force microscopy (AFM) and alternative current (A.C) impedance suggest that the enhancement of the light-to-current conversion efficiency is raised from the lower value of charge transfer resistance of the cell. Under the standard air mass (AM) 1.5 condition of 20 mW/cm² irradiation intensity, the open circuit voltage (V_oc), short circuit current (J_sc), maximum power voltage (V_mp), and maximum power current (J_mp) of the PV device were 0.64 V, 0.83 A/cm², 0.2 V, and 0.38 A/cm², respectively.