Perovskite solar cells with graphite electrodes: Advanced interfaces for highest performance and stability (PeroGAIN)

在PeroGAIN项目中，将评估基于碳-石墨电极的钙钛矿太阳能电池(PSC)中的界面和相关的损耗机制。与基于金属电极的器件相比，这种类型的PSC已经显示出卓越的器件稳定性，并具有在环境条件下生产全印刷光伏组件的前景，从而实现最低的生产成本和二氧化碳排放量。碳基设备的最高稳定性是使用需要在高温(HT)下烧结的碳糊来实现的，这限制了工艺和设备架构方面的灵活性。采用低温碳(LT-C)浆料，可以获得更高的功率转换效率值。然而，与金属电极PSC相比，这些器件的效率仍有很大差距，而且还没有达到与相关HT-C器件类似的高稳定值。同时，到目前为止，关于LT-C PSC稳定性的研究还很有限。PeroGAIN旨在通过先进的表征和建模，加深对LT-C PSC界面性能损失和退化机理的了解，找出阻碍器件效率和稳定性的关键因素。为此，将分析单独的功能层、层组合和完整的器件堆栈的物理特性以及钙钛矿、碳电极和相邻接触层之间的界面形成。此外，LT-C PSC的稳定性将在相关的加速老化试验和户外运行中进行评估。先进的光电子器件表征与再现实验行为的数值器件模拟相结合，将有助于加深对完整太阳能电池堆栈中多个界面处潜在物理的理解，并阐明吸收层/碳界面处非理想接触形成的影响。从所获得的知识中，将衍生出释放LT-C PSC全部潜力的策略。这将允许通过钝化、掺杂或引入额外的电荷选择层来修改界面，并评估其对器件效率和稳定性的影响。如此一来，上述损耗将得到缓解，并产生稳定的器件，从而有效地缩小与金属电极PSC的差距。

In the PeroGAIN project, interfaces and associated loss mechanisms in perovskite solar cells (PSC) based on carbon-graphite electrodes will be assessed. This type of PSC has already shown superior device stability in comparison to metal-electrode based devices and features the prospect of producing fully printed PV modules at ambient conditions, enabling lowest production cost and CO2 footprint. Highest stabilities of carbon-based devices have been reached with carbon pastes which require sintering at high temperatures (HT), limiting the flexibility with regards to processing and device architecture. Employing low temperature carbon (LT-C) pastes, higher power conversion efficiency values could be reached. However, there is still a significant efficiency gap of these devices when compared to metal-electrode PSC, and similarly high stability values as for the related HT-C devices have not been achieved. At the same time, only a limited number of studies focusing on the stability of LT-C PSC has been performed until now.PeroGAIN aims to deepen the understanding of the interfaces in LT-C PSC with respect to both performance loss as well as degradation mechanisms by advanced characterization and modelling, identifying key factors that hinder device efficiency and stability. To this end, individual functional layers, layer combinations and full device stacks will be analysed with respect to their physical properties and interface formation between perovskite, carbon electrode and adjacent contact layers. Furthermore, the stability of LT-C PSC will be assessed in relevant accelerated aging tests and outdoor operation. Advanced optoelectronic device characterization combined with numerical device simulations for reproduction of experimental behavior will lead to an increased understanding of underlying physics at the multiple interfaces in complete solar cell stacks and elucidate the impact of non-ideal contact formation at the absorber/carbon interface.From the gained knowledge, strategies to unlock the full potential of LT-C PSC will be derived. This will allow interface modification by passivation, doping or introduction of additional charge selective layers and assessment of its effect on device efficiency and stability. By this, aforementioned losses will be mitigated and result in stable devices with efficiencies closing the gap to metal-electrode based PSC.