Single-walled carbon nanotube as hole transport layer in perovskite solar cell: Efficiency enhancement

We propose a new hole transport layer (HTL) in a perovskite solar cell (PSC) using single-walled carbon nanotube (SWCNT) achieving a power conversion efficiency (PCE) up to 19.98%, for the first time. Owing to its exceptional quantum properties, this one-dimensional (1D) element is utilized in order to facilitate hole transport inside the cell structure. Using (6, 5) SWCNT as the HTL and the MAPbI3 perovskite material on top of it as the main adsorbent layer, while colloidal quantum dots (CQDs) of lead sulfide (PbS-CQDs) with excellent absorption in the wavelength range of 500–1100 nm fills the space around the SWCNTs in each unit cell as the second adsorbent layer, we achieved excellent performance. Also, we observe a 49.7% increase compared to when the space around the HTL is filled with perovskite material. The proposed PSC arrangement, due to its brilliant electrical and mechanical properties besides excellent stability of SWCNTs, gives significantly superior cell stability in addition to a high PCE. Finally, we hope that utilizing this novel structure can be extended in the industry along with solving problem of perovskite stability.