The investigation of dependence of optoelectronic properties of P^HT:PCBM based organic solar cells on layer thicknesses

This paper presents the production and results of optoelectronic characterization process for ITO/PEDOT:PSS/P3HT:PCBM/Al organic solar cells (OSC). OSCs were produced in open air environment with various P3HT:PCBM active layer thicknesses of 70, 110, 140, 175 and 190 nm. The diode properties of the solar cells in the dark have been investigated by using current-voltage (I-V) measurements. Using the results of the measurements, diode ideality factors for all cells were calculated to be 3.96, 3.89, 3.43, 3.31, and 3.29, respectively. The absorption characteristics have been investigated by using transmission spectroscopy, and optical band gap energy (Eg) for each sample has been calculated to be 1,71; 1,71; 1,70; 1,69 ve 1,67 eV, respectively. The cell parameters for each solar cell were analyzed by using current density-voltage (J-V) measurements under AM 1.5 solar radiation. Some important solar cell parameters such as open circuit voltage (Voc), short circuit current density (Jsc), maximum cell power (Pmax), fill factor (FF) and power conversion efficiency (PCE) were calculated by using the data obtained from the measurements. As a result of the calculations, % PCE values of the cells were found to be 0.39; 0.53; 0.59; 0.54 and 0.51, respectively. It was observed that fill factor (FF) value of the solar cells increase between 0,3239 and 0,3409 with decreasing n value. The highest value of PCE was found to be 0,59, which belongs to the cell having 140 nm P3HT:PCBM thickness.