Improved performance of P3HT：PCBM solar cells by both anode modification and short-wavelength energy utilization using Tb(aca)₃phen

The performance of P3HT:PCBM solar cells was improved by anode modification using spin-coated Tb(aca)₃phen ultrathin films. The modification of the Tb(aca)₃phen ultrathin film between the indium tin oxide (ITO) anode and the PEDOT:PSS layer resulted in a maximum power conversion efficiency (PCE) of 2.99% compared to 2.66% for the reference device, which was due to the increase in the short-circuit current density (J_sc). The PCE improvement could be attributed to the short-wavelength energy utilization and the optimized morphology of the active layers. Tb(aca)₃phen with its strong down-conversion luminescence properties is suitable for the P3HT:PCBM blend active layer, and the absorption region of the ternary blend films is extended into the near ultraviolet region. Furthermore, the crystallization and the surface morphology of P3HT:PCBM films were improved with the Tb(aca)₃phen ultrathin film. The ultraviolent-visible absorption spectra, atomic force microscope (AFM), and X-ray diffraction (XRD) of the films were investigated. Both anode modification and short-wavelength energy utilization using Tb(aca)₃phen in P3HT:PCBM solar cells led to about a 12% PCE increase.