Controlled n‐Doping in Air‐Stable CsPbI₂Br Perovskite Solar Cells with a Record Efficiency of 16.79%

Abstract

Cesium‐based inorganic perovskites, such as CsPbI2Br, are promising candidates for photovoltaic applications owing to their exceptional optoelectronic properties and outstanding thermal stability. However, the power conversion efficiency of CsPbI2Br perovskite solar cells (PSCs) is still lower than those of hybrid PSCs and inorganic CsPbI3 PSCs. In this work, passivation and n‐type doping by adding CaCl2 to CsPbI2Br is demonstrated. The crystallinity of the CsPbI2Br perovskite film is enhanced, and the trap density is suppressed after adding CaCl2. In addition, the Fermi level of the CsPbI2Br is changed by the added CaCl2 to show heavy n‐type doping. As a result, the optimized CsPbI2Br PSC shows a highest open circuit voltage of 1.32 V and a record efficiency of 16.79%. Meanwhile, high air stability is demonstrated for a CsPbI2Br PSC with 90% of the initial efficiency remaining after more than 1000 h aging in air.

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

“…The burgeoning organic halide perovskite solar cells (PSCs) with the skyrocketing power conversion efficiency (PCE) from 3.8% to 25.2% have been regarded as the promising candidate for next-generation solar cells. [1][2][3][4][5][6][7][8][9] However, the most commonly used organic cations, such as methylammonium (MA) and formamidinium (FA), are volatile and vulnerable to photo, thermal, and moisture stresses.…”

“…[23,24] To the best of our knowledge, CsPbI 2 Br with a bandgap of 1.92 eV possesses a highest PCE of 16.79% by n-type doping strategy. [25] However, the air stability of the CsPbI 2 Br PSCs is still unsatisfied. [26] Intriguingly, CsPbIBr 2 with a wider bandgap of 2.08 eV and prolonged thermal stability has been integrated into the photovoltaic application.…”

Effective Surface Treatment for High-Performance Inverted CsPbI2Br Perovskite Solar Cells with Efficiency of 15.92%

“…Among them, endowed with good phase stability and appropriate light absorption (1.81-1.92 eV), CsPbI 2 Br reveals the most promising for photovoltaic application like top cell of tandem cells [7,8]. To date, a high efficiency of 16.79% has been realized with a regular structure (n-i-p) CsPbI 2 Br perovskite solar cells (PSCs) [9]. However, as universally used HTL materials, the 2,2′,7,7′-tetrakis (N,N-dipmethoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) and poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA) always need additional dopant of hygroscopic bis(trifluoromethanesulfonyl)imide lithium salt (Li-TFSI) and low-boil-point tert-butylpyridine (t-BP) to increase holes mobility [10][11][12][13][14].…”

Unravelling the theoretical window to fabricate high performance inorganic perovskite solar cells

“…The most efficient CsPbI2Br based PSCs yielded PCE of 16.79 % with an Voc of 1.32 V, i.e. Eloss = 0.59 eV 22 . The toxicity of the lead (Pb) metal is visualized as a barrier for commercial success of inorganic PSCs.…”