p-Spiro-OMeTAD/Sb-doped n-CsPbBr3 heterojunction perovskite solar cell without electron transport layer

The development of simplified, stable, and efficient device architectures is crucial for advancing perovskite solar cells (PSCs) toward commercialization. Herein, we report an electron transport-layer-free (ETL-free) all-inorganic PSC based on a p-Spiro-OMeTAD/n-Sb-doped CsPbBr 3 heterojunction. By employing SbBr 3 as the dopant, high-quality n-type Sb-doped CsPbBr 3 perovskite films are successfully prepared via pulsed laser deposition (PLD) method. Comprehensive analyses using ultraviolet photoelectron spectroscopy (UPS) and Hall effect measurements confirm that Sb 3+ doping converts the conductivity type of the CsPbBr 3 film from quasi-intrinsic weak p-type to clear n-type, accompanied by a significant enhancement in electrical conductivity. The CsPbBr 3 :Sb film serves as both the light-absorption layer and ETL, and forms a p-n heterojunction with p‑type Spiro‑MeOTAD. This heterojunction structure with proper interface band bending facilitates both hole extraction and electron blocking. The final device has a power conversion efficiency (PCE) of 9.05%, and exhibits excellent long-term environmental stability (after 500 hours of continuous operation, the efficiency remains above 90% of the initial efficiency). This work establishes a viable pathway for the development of efficient, stable, and simplified all-inorganic perovskite photovoltaics. • SbBr 3 as the dopant and high-quality Sb-doped CsPbBr 3 (CsPbBr 3 :Sb) perovskite films were successfully grown by pulsed laser deposition (PLD) method. • The conductivity type of the CsPbBr 3 film is transformed from a quasi-intrinsic weak p-type to a clear n-type upon Sb 3+ doping. • The devices based on n-CsPbBr 3 :Sb/p-spiro-MeOTAD heterojunction achieved an efficiency of 9.05%, which is higher than that of the undoped devices.