Interface Modulator of Ultrathin Magnesium Oxide for Low‐Temperature‐Processed Inorganic CsPbIBr₂ Perovskite Solar Cells with Efficiency Over 11%

Abstract

Although the power conversion efficiency (PCE) of thermally stable inorganic CsPbIBr2 perovskite solar cells (PSCs) is over 10%, the severe interfacial and nonradiative recombination deteriorates the open‐circuit voltage (Voc). Herein, an ultrathin wideband MgO is mediated between the SnO2 electron transport layer (ETL) and the CsPbIBr2 photoabsorber to passivate the undesirable recombination, thereby enhancing the Voc. Meanwhile, the δ‐phase perovskite located at the interface between SnO2 ETL and CsPbIBr2 film is reduced after MgO modification, because the MgO layer provides a substrate for perovskite growth and reduces vacancy. Moreover, the tunneling effect and better band alignment effectively block holes and accelerate electrons to the electrode. Consequently, for optimal MgO‐modified devices, a shining improvement of Voc from 1.25 to 1.36 V without short‐circuit current losses boosts the champion CsPbIBr2 PSCs to obtain a PCE of 11.04%, which is the highest value among the pure‐CsPbIBr2 PSCs. However, the MgO layer significantly reduces severe hysteresis and increases device stability.

High‐Efficiency Carbon‐Based CsPbIBr2 Solar Cells with Interfacial Energy Loss Suppressed by a Thin Bulk‐Heterojunction Layer

“…The increased V bi can promote faster dissociation of photogenerated carriers and form a wide depletion region to inhibit recombination. [41,42] In addition, the donor density (N d ) of the corresponding device can also be obtained from the Mott-Schottky curves with Equation (5) [43] 1…”

Interface Engineering for All‐Inorganic CsPbIBr2 Perovskite Solar Cells with Enhanced Power Conversion Efficiency over 11%

“…When the currents increase out of control, the device shows a trap‐filled limit (TFL) response, and the corresponding voltage of the kink point is determined as the trap‐filling limited voltage ( V TFL ). [ 77 ] Therefore, the defect density ( N ) of each film could be obtained from the equation: V TFL = , wherein e is the elementary charge, L is the film thickness, and ε and ε 0 represent relative dielectric constant and the permittivity of vacuum, respectively. [ 78,79 ] The values of N in the SnO 2 ‐based CsPbIBr 2 and the SnO 2 /PEIE‐based CsPbIBr 2 film were calculated to be 1.11 × 10 16 and 8.84 × 10 15 cm −3 , respectively.…”

p‐Type Charge Transfer Doping of Graphene Oxide with (NiCo)1−yFeyOx for Air‐Stable, All‐Inorganic CsPbIBr2 Perovskite Solar Cells

“…However, an inevitable compromise between efficiency and long‐term stability persists upon changing the halogen content, leading to the best environment tolerance for CsPbBr 3 perovskite [10] and the highest PCE for CsPbI 3 perovskite [11] . By balancing the efficiency and stability, the mixed halide CsPbIBr 2 perovskite is regarded as a potential material in real application especially in tandem photovoltaics [12–15] . In comparison to the state‐of‐the‐art hybrid PSCs, the best efficiency of CsPbIBr 2 PSCs is still far from their theoretical limit, which is mainly attributed to the substantial charge recombination at grain boundaries and/or interfaces [16, 17] .…”