Ultrafast Photogenerated Hole Extraction/Transport Behavior in a CH₃ NH₃ PbI₃ /Carbon Nanocomposite and Its Application in a Metal-Electrode-Free Solar Cell

Aligned and flexible electrospun carbon nanomaterials are used to synthesize carbon/perovskite nanocomposites. The free-electron diffusion length in the CH₃ NH₃ PbI₃ phase of the CH₃ NH₃ PbI₃ /carbon nanocomposite is almost twice that of bare CH₃ NH₃ PbI₃ , and nearly 95 % of the photogenerated free holes can be injected from the CH₃ NH₃ PbI₃ phase into the carbon nanomaterial. The exciton binding energy of the composite is estimated to be 23 meV by utilizing temperature-dependent optical absorption spectroscopy. The calculated free carriers increase with increasing total photoexcitation density, and this broadens the potential of this material for a broad range of optoelectronics applications. A metal-electrode-free perovskite solar cell (power conversion efficiency: 13.0 %) is fabricated with this perovskite/carbon composite, which shows great potential for the fabrication of efficient, large-scale, low-cost, and metal-electrode-free perovskite solar cells.