The Research Of Polymer Solar Cells By Air-brush Spraying

This paper used polymer solar cells’common materials such as PEDOT:PSS, P3HT and PCBM as samples, analysed the regularity of polymer films by air-brush spraying and studied the performance of relevant polymer solar cells, summarized the rules of influence on polymer solar cells with air-brush spraying at different substrate temperature and different annealing time.First of all, the buffer layer PEDOT:PSS films and the active layer P3HT:PCBM films are deposited with air-brush at different substrate temperatures respectively. We make research of the effect of substrate temperature on PEDOT:PSS films and P3HT:PCBM films. The experimental results show that, deposition process of air-brush spraying is composed of the accumulation by several dried micron droplet on the substrate, and the individual droplet height difference can be controled by the substrate temperature. When the substrate temperature is lower, the height difference of individual droplet is smaller, and the film roughness is smaller; otherwise the film roughness will increase.Then we make research of the effect of substrate temperature on polymer solar cells and its modification mechanism. Substrate temperature is the major fact that influences the droplet’s evaporation rate when reaching the substrate, thus it has a direct effect on the solute crystallization process. As the substrate temperature increases, the surface roughness of the films will increase, thus it increases the contact area with the bulk hetero-junction and improves the carrier transmission and collection efficiency. The experiment of air-brush spraying PEDOT:PSS film in polymer solar cells indicates that when substrate temperature is130℃, the short circuit current(Isc), open circuit voltage(Voc), the fill factor (FF), efficiency (PCE)are:11.51mA/cm2,0.57V,28.69%,1.87%.In the end, we make a comparison of films annealed at different time. It is indicated that when the films annealed at140℃for30minutes, device short-circuit current was increased from4.39mA/cm2to5.79mA/cm2, while the conversion efficiency is only about0.49%. But we can improve the performance of devices by different aspects such as joining the anode buffer layer or changing the device structure.