Low-temperature carbon-based counter electrodes for hole transport free perovskite solar cells fabricated in ambient conditions

Abstract

Perovskite solar cells are the much talked about and researched devices in the photovoltaic community. Most high-efficiency solar cells are prepared using an expensive hole transport layer which is unstable in ambient atmosphere, and an energy consuming method of depositing the cathode to complete the cell. Herein, following recommendations from literature, carbon-based nanomaterials are utilized in the fabrication of Perovskite solar cells, and its effects on the efficiency, fill factor, open circuit voltage, short circuit density, and hysteresis is analyzed. The Perovskite solar cells and carbon counter electrodes fabricated at low temperature (~100 degrees Celsius) and in room temperature conditions. Multi-walled carbon nanotubes based devices exhibited an efficiency of ~7%. This endeavor further buttresses the fact that carbon nanomaterials - especially MWCNTs are promising candidates for the future of low cost, high performance and scalable production of Perovskite solar cells. Thus, expensive hole transport materials and complex vacuum deposition of cathodes to complete the cells might be eliminated. The difference factors of average efficiencies from the different scan directions appear to show that hysteresis effect is minimal in the MWCNT based devices.