Thermally stimulated infrared spectroscopy and its application to molecular structure analysis of carrier traps in organic semiconductor thin films

研究了有机薄膜太阳能电池活性材料PEDOT:PSS/P3HT:PCBM薄膜在532 nm光照射下的红外光谱变化。照射60 min后观察光谱变化。观察到的光谱可能是由于P3HT中捕获的正极化子和光照射产生的化学物质导致的能带重叠。它们在室温下是稳定的。随着温度的升高，光谱发生了较大的变化，这与PEDOT:PSS的光谱变化有关。因此，很难获得捕获极化子的活化能。我们将通过测量不同温度下的反应速率来得到活化能。

We have studied infrared spectral changes of PEDOT:PSS/P3HT:PCBM films, which are active materials of organic thin film solar cells, upon irradiation of 532 nm light. Spectral changes were observed upon 60 min irradiation. The observed spectra are likely attributed to the overlaps of the bands due to trapped positive polarons in P3HT and chemical species generated by light irradiation. They are stable at room temperature. Large spectral changes were observed with increasing temperature, which are attributed to the changes of spectrum of PEDOT:PSS. Thus, it is difficult to obtain the activation energy of the trapped polarons. We will obtain the activation energy by measuring the rate of the reactions at several temperatures.