单光子计数法对光生载流子寿命的测量与分析

Measurement and Analysis on the Lifetime of Optical Carriers by Time Correlated Single Photon Counting

采用单光子计数法(Time Correlated Single Photon Counting,TCSPC)测量了MEH-PPV和CdS共混薄膜退火处理前后受到超短脉冲激光激发及光生载流子的瞬态衰减过程,得到了MEH-PPV:CdS共混薄膜材料的光生载流子寿命。分析表明,退火处理后MEH-PPV:CdS共混薄膜材料的光生载流子寿命更长,相应的光伏器件(结构为ITO/PEDOT:PSS/MEH-PPV:CdS/Al的有机薄膜光伏器件)也具有较高的光电转换效率。

Photogenerated carrier lifetime is one of the key and difficult points in the teaching of semiconductor physics. In order to make students understand this abstract concept better, time correlated single photon counting(TCSPC) technique is used to measure the transient decay process of photogenerated carriers in the blend films of MEH-PPV and CdS. The results show that the photogenerated carrier life of the annealed MEH-PPV: CdS blend film is longer than that of unannealed one, and the corresponding photovoltaic devices(organic film photovoltaic devices with ITO/PEDOT: PSS/MEH-PPV: CdS/Al structure) also have higher photoelectric conversion efficiency. Through the measurement of photocarrier lifetime by TCSPC technology, namely the practical application of TCSPC technology in the research of organic thin film solar cells, it is helpful for students to understand the concept of photogenerated carrier lifetime and master the principle of TCSPC technology and the experimental method of transient fluorescence spectrum.