Nanospacer‐Supported Carbon Nanotube Hybrid Electrode for Efficient and Stable Carbon‐Based Perovskite Solar Cells

Abstract Device production costs must be reduced to achieve commercializatio hybrid perovskite solar cells (PSCs). Carbon‐based materials are promising alternatives to conventional noble metal top electrodes and offer cost‐effective solutions. However, the performance of PSCs employing carbon‐based top electrodes is inferior to that using gold electrodes, primarily because of suboptimal interfacial design. In this study, an inorganic nanospacer (NS) is introduced at the interface between a perovskite and hole‐transporting material (HTM)‐infiltrated carbon nanotubes (CNTs). The NS reduces nonradiative recombination by preventing direct contact between the perovskite and CNTs while also facilitating efficient hole transport from the perovskite to the CNTs. Consequently, a solar cell using a CNT‐HTM hybrid electrode achieves a power conversion efficiency of 22.6% (certified efficiency: 22.5%). The device maintains its efficiency after 1200 h of continuous operation at room temperature. Furthermore, after an additional 500 h of operation at 60 °C, it retains over 80% of its initial efficiency. In addition, a photocapacitor integrating this solar cell with a supercapacitor exhibits an overall efficiency of 16.9%, which is comparable to those of GaAs and multijunction solar cell‐based photocapacitor systems.