Recent Progresses on Defect Passivation toward Efficient Perovskite Solar Cells

Organic-inorganic hybrid perovskite materials are receiving increasing attention and becoming star materials on account of their unique and intriguing optical and electrical properties, such as high molar extinction coefficient, wide absorption spectrum, low excitonic binding energy, ambipolar carrier transport property, long carrier diffusion length, and high defects tolerance. Although a high power conversion efficiency (PCE) of up to 22.7% is certified for perovskite solar cells (PSCs), it is still far from the theoretical Shockley-Queisser limit efficiency (30.5%). Obviously, trap-assisted nonradiative (also called Shockley-Read-Hall, SRH) recombination in perovskite films and interface recombination should be mainly responsible for the above efficiency distance. Here, recent research advancements in suppressing bulk SRH recombination and interface recombination are systematically investigated. For reducing SRH recombination in the films, engineering perovskite composition, additives, dimensionality, grain orientation, nonstoichiometric approach, precursor solution, and post-treatment are explored. The focus herein is on the recombination at perovskite/electron-transporting material and perovskite/hole-transporting material interfaces in normal or inverted PSCs. Strategies for suppressing bulk and interface recombination are described. Additionally, the effect of trap-assisted nonradiative recombination on hysteresis and stability of PSCs is discussed. Finally, possible solutions and reasonable prospects for suppressing recombination losses are presented.

Causes and Solutions of Recombination in Perovskite Solar Cells

The power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) are already higher than that of other thin film technologies, but laboratory cell-fabrication methods are not scalable. Here, we report an additive strategy to enhance the efficiency and stability of PSCs made by scalable blading. Blade-coated PSCs incorporating bilateral alkylamine (BAA) additives achieve PCEs of 21.5 (aperture, 0.08 cm2) and 20.0% (aperture, 1.1 cm2), with a record-small open-circuit voltage deficit of 0.35 V under AM1.5G illumination. The stabilized PCE reaches 22.6% under 0.3 sun. Anchoring monolayer bilateral amino groups passivates the defects at the perovskite surface and enhances perovskite stability by exposing the linking hydrophobic alkyl chain. Grain boundaries are reinforced by BAA and are more resistant to mechanical bending and electron beam damage. BAA improves the device shelf lifetime to >1000 hours and operation stability to >500 hours under light, with 90% of the initial efficiency retained.

Bilateral alkylamine for suppressing charge recombination and improving stability in blade-coated perovskite solar cells.

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

Multifunctional Enhancement for Highly Stable and Efficient Perovskite Solar Cells

NbF5: A Novel α-Phase Stabilizer for FA-Based Perovskite Solar Cells with High Efficiency

Research on the addition of suitable materials into perovskite film for improved quality is important to fabricate efficient and stable perovskite solar cells An attempt to enhance the quality of perovskite is performed by incorporation of a bifunctional hydroxylamine hydrochloride (HaHc) into pristine perovskite solution On the one hand, the chloride ion in HaHc changes the crystallization kinetic and defect state of the perovskite film and a high-quality perovskite film with larger grain size and lower defect density is obtained Perovskite solar cell (PSC) with HaHc additive exhibit a power conversion efficiency (PCE) of 1869% with less hysteresis, which is obviously higher than that of pristine cells (1685%) On the other hand, the hydroxyl group in HaHc can form a strong hydrogen bond with iodide ion in perovskite film to impede the decomposition of the film when under thermal annealing or storing in air As a result, the PSCs with HaHc additive show superior thermal and air stability to the pris

Qiang Wang

Papers

NbF5: A Novel α-Phase Stabilizer for FA-Based Perovskite Solar Cells with High Efficiency

Bifunctional Hydroxylamine Hydrochloride Incorporated Perovskite Films for Efficient and Stable Planar Perovskite Solar Cells