Wagner Lukas, Mundt Laura E, Mathiazhagan Gayathri, Mundus Markus, Schubert Martin C, Mastroianni Simone, Würfel Uli, Hinsch Andreas, Glunz Stefan W
Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, D-79110, Freiburg, Germany.
Freiburg Materials Research Center FMF, Albert-Ludwigs-University Freiburg, Stefan-Meier-Straße 25, D-79140, Freiburg, Germany.
Sci Rep. 2017 Nov 2;7(1):14899. doi: 10.1038/s41598-017-13855-6.
Relating crystallization of the absorber layer in a perovskite solar cell (PSC) to the device performance is a key challenge for the process development and in-depth understanding of these types of high efficient solar cells. A novel approach that enables real-time photo-physical and electrical characterization using a graphite-based PSC is introduced in this work. In our graphite-based PSC, the device architecture of porous monolithic contact layers creates the possibility to perform photovoltaic measurements while the perovskite crystallizes within this scaffold. The kinetics of crystallization in a solution based 2-step formation process has been analyzed by real-time measurement of the external photon to electron quantum efficiency as well as the photoluminescence emission spectra of the solar cell. With this method it was in particular possible to identify a previously overlooked crystallization stage during the formation of the perovskite absorber layer. This stage has significant influence on the development of the photocurrent, which is attributed to the formation of electrical pathways between the electron and hole contact, enabling efficient charge carrier extraction. We observe that in contrast to previously suggested models, the perovskite layer formation is indeed not complete with the end of crystal growth.
将钙钛矿太阳能电池（PSC）中吸收层的结晶与器件性能相关联，对于这类高效太阳能电池的工艺开发和深入理解而言是一项关键挑战。本文介绍了一种新颖的方法，该方法能够使用基于石墨的PSC进行实时光物理和电学表征。在我们基于石墨的PSC中，多孔整体接触层的器件结构使得在钙钛矿在该支架内结晶时进行光伏测量成为可能。通过实时测量外部光子到电子的量子效率以及太阳能电池的光致发光发射光谱，分析了基于溶液的两步形成过程中的结晶动力学。使用这种方法，特别有可能识别出在钙钛矿吸收层形成过程中一个先前被忽视的结晶阶段。这个阶段对光电流的发展有重大影响，这归因于电子和空穴接触之间形成了电通路，从而实现了有效的电荷载流子提取。我们观察到，与先前提出的模型相反，钙钛矿层的形成在晶体生长结束时确实并未完成。
