Study of energy loss mechanisms in organic thin film solar cells by using quantum beam based analytical techniques

在本研究中，我们用紫外光电子能谱研究了电极缓冲层的电学性质，用光电子能谱和芯-空穴钟谱研究了分子/电极界面的电荷转移速度，发现金属到分子的电子掺杂导致了有效的电极接触，即在电极界面发生了小于10fs的高速电荷转移。此外，很明显，电子掺杂影响了两个或更多有机层的能级排列。因此，控制有机/金属界面的电子掺杂对于选择最佳的器件结构是不可或缺的，这显然成为实现高效OSCS的关键。

In this research, we have investigated(1) electronic properties of electrode buffer layers by means of ultraviolet photoelectron spectroscopyand (2) the charge transfer speed at molecule/electrode interfaces by means of photoelectron spectroscopy and core-hole clock spectroscopy.It was found that electrondoping from metal to molecule results in effective electrode contact; that is, the high speed charge transfer of less than 10 fs happens at electrode interfaces. Moreover, it became clear that the electrondoping affected energy level alignment of two or more organic layers. Thus, control of electron doping at organic/metal interface is indispensable to selection of the optimal device structure, and it became clear to become a key to highly efficient OSCs.