时间分离的光致发光of organic solar cells

时间分离的光致发光

TR-PL是一种强大的技术，用于探测半导体材料内的激发力转变的动态，例如基于薄膜的光伏的光伏。

恩里科·德·科莫博士和同事Ludwig-Maximilians- University Munich, Germany, are using the technique to investigate the efficiency of organic solar cells. Organic solar cells may offer key benefits such as high efficiencies, low costs and ease of production. Such cells typically consist of thin films of conjugated polymer with a fullerene layer. They rely upon photo-induced charge transfer occurring between the light harvesting conjugated polymer and the strong acceptor fullerene layer. The charge transfer excitons (CTEs) formed in this process have a limited lifetime. Photoluminescence from de-excitation of excitons is one of the most important recombination mechanisms that occurs; recombination impacts directly on the efficiency of such structures.

图1：用新的ISTAR模型DH340T-18U-03拍摄的PL光谱系列，安装在三叶草500i上。激光激发来自脉冲激光器。

通过用耦合到三叶草500i光谱仪的ISTAR ICCD摄像机分析光致发光来研究细胞CTE的衰减动态。使用脉冲激光（Ti-Sapphire，540nm，Rep率90 kHz）激发样品并触发ISTAR。图2示出了由可见区域中的光致发光光谱的DH340T-18U-03相机捕获的动力学系列。每个光致发光光谱都有5 ns门宽和5 ns的线性步延迟。每个延迟的信号被累积在激光器中的频率I. 90 kHz。通过考虑通过型材的一馏分的集成强度，可以绘制衰减特性和从电力法模型确定的寿命。在此实验期间测量20ns和40 ns之间的衰减时间。