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

Abstract

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.

Reducing Detrimental Defects for High‐Performance Metal Halide Perovskite Solar Cells

“…On the basis of our survey (Table S2), another key message is that none of the passivation strategies can eliminate the defects completely and they can only reduce the defect density to a certain degree (1 to 2 orders of magnitude lower) –. In all of these studies, the TAS technique was the main technique employed to compare the defect densities before and after the passivation.…”

“…The subsequent larger number of publications deals on 2) negatively charged Pb–I anti‐sites (PbI 3 − ) or halide‐excess (16 out of 72), followed by 3) cation vacancies surface termination (e.g., Cs + , MA + ; 6 out of the 72 studies surveyed in this Review), 4) mobile or volatile iodine and MA + cation (4 out of the 72 studies surveyed in this Review), 5) metallic lead (Pb 0 ) surface terminated (3 out of the 72 studies surveyed in this Review), and 6) I 0 (I 2 ) defects (2 out of the 72 studies surveyed in this Review). Because multiple different types of defects are present, it is important to adopt passivating molecules that have dual functions of Lewis base and Lewis acid to passivate effectively both types of positively and negatively charged defects simultaneously (Figure ) –. However, for instance, even though a perovskite surface “free” of charged defects is attained, there is evidence that halides located at the grain boundaries are mobile under an electric field.…”

Comparative studies of optoelectrical properties of prominent PV materials: Halide perovskite, CdTe, and GaAs

“…MAPbI3 samples from three different sources are used in this study: (1) Polycrystalline thin films of University of North Carolina at Chapel Hill group [41]: one consists of ~200 nm size grains under SEM but with smooth surface morphology under optical microscope (referred to as "UNC"), and another consists of ~250 nm size grains under SEM and 50 m domains under optical microscope, both being about 500 nm in thickness. The second sample has an oxysalt protection layer on top for the purpose of surface passivation and protection ("UNC-passivated") [42].…”

Metal Halide Perovskites for Solar‐to‐Chemical Fuel Conversion

“…For photocatalyst particle‐suspension systems, water/moisture instability issues associated with halide perovskites must be considered. Halide perovskites generally cannot resist water, even though some strategies can render them stable against a certain percentage of humidity . To this end, researchers have expended great efforts by developing water‐stable perovskite and structures, discovering proper proton sources (e.g., hydrogen iodide, HI) other than water, and dispersing halide perovskite in non‐aqueous solutions for CO 2 reduction.…”