Redondo-Obispo C, Serafini P, Climent-Pascual E, Ripolles T S, Mora-Seró I, de Andrés A, Coya C
Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
Institute of Advanced Materials (INAM), Universitat Jaume I, 12071 Castelló, Spain.
ACS Appl Energy Mater. 2021 Dec 27;4(12):13943-13951. doi: 10.1021/acsaem.1c02738. Epub 2021 Nov 17.
The relatively low stability of solar cells based on hybrid halide perovskites is the main issue to be solved for the implementation in real life of these extraordinary materials. Degradation is accelerated by temperature, moisture, oxygen, and light and mediated by halide easy hopping. The approach here is to incorporate pristine graphene, which is hydrophobic and impermeable to gases and likely limits ionic diffusion while maintaining adequate electronic conductivity. Low concentrations of few-layer graphene platelets (up to 24 × 10 wt %) were incorporated to MAPbI films for a detailed structural, optical, and transport study whose results are then used to fabricate solar cells with graphene-doped active layers. The lowest graphene content delays the degradation of films with time and light irradiation and leads to enhanced photovoltaic performance and stability of the solar cells, with relative improvement over devices without graphene of 15% in the power conversion efficiency, PCE. A higher graphene content further stabilizes the perovskite films but is detrimental for in-operation devices. A trade-off between the possible sealing effect of the perovskite grains by graphene, that limits ionic diffusion, and the reduction of the crystalline domain size that reduces electronic transport, and, especially, the detected increase of film porosity, that facilitates the access to atmospheric gases, is proposed to be at the origin of the observed trends. This work demonstrated how the synergy between these materials can help to develop cost-effective routes to overcome the stability barrier of metal halide perovskites, introducing active layer design strategies that allow commercialization to take off.
基于混合卤化物钙钛矿的太阳能电池相对较低的稳定性是这些非凡材料在实际应用中需要解决的主要问题。温度、湿度、氧气和光照会加速降解，卤化物的易跳跃介导了这种降解。这里的方法是引入原始石墨烯，它具有疏水性且对气体不可渗透，可能会限制离子扩散，同时保持足够的电子导电性。将低浓度的几层石墨烯薄片（高达24×10 wt%）掺入MAPbI薄膜中，进行详细的结构、光学和传输研究，然后将研究结果用于制造具有石墨烯掺杂活性层的太阳能电池。最低的石墨烯含量可延缓薄膜在时间和光照下的降解，并提高太阳能电池的光伏性能和稳定性，与不含石墨烯的器件相比，功率转换效率（PCE）相对提高了15%。较高的石墨烯含量进一步稳定了钙钛矿薄膜，但对运行中的器件不利。有人提出，石墨烯对钙钛矿晶粒可能的密封作用（限制离子扩散）与晶体域尺寸减小（降低电子传输）之间的权衡，特别是检测到的薄膜孔隙率增加（便于大气气体进入），是观察到的趋势的根源。这项工作展示了这些材料之间的协同作用如何有助于开发经济高效的途径来克服金属卤化物钙钛矿的稳定性障碍，引入了能够推动商业化发展的活性层设计策略。
