Cesium Lead Halide Perovskites with Improved Stability for Tandem Solar Cells

Abstract

A semiconductor that can be processed on a large scale with a bandgap around 1.8 eV could enable the manufacture of highly efficient low cost double-junction solar cells on crystalline Si. Solution-processable organic-inorganic halide perovskites have recently generated considerable excitement as absorbers in single-junction solar cells, and though it is possible to tune the bandgap of (CH3NH3)Pb(BrxI1-x)3 between 2.3 and 1.6 eV by controlling the halide concentration, optical instability due to photoinduced phase segregation limits the voltage that can be extracted from compositions with appropriate bandgaps for tandem applications. Moreover, these materials have been shown to suffer from thermal degradation at temperatures within the processing and operational window. By replacing the volatile methylammonium cation with cesium, it is possible to synthesize a mixed halide absorber material with improved optical and thermal stability, a stabilized photoconversion efficiency of 6.5%, and a bandgap of 1.9 eV.

Methodologies toward Efficient and Stable Cesium Lead Halide Perovskite‐Based Solar Cells

“…The solar cells based on this material exhibited a champion PCE of 9.8%, which was the highest record at that time (Figure 2a, right). At a similar time, same experimental result was reported by Beal et al22 …”

“…It was verified that a moderate annealing temperature significantly reduced the surface and bulk defect sites (metallic Pb and halide vacancy) and preserved the cationic charge of Pb cations, thereby enhancing the photovoltaic performance as well as the phase stability. The optimized solar cell exhibited a PCE of 10.7%, and in particular, the V OC of this device was 1.23 eV, which far outperformed that of the earlier reported devices 21, 22, 23. Overall, thanks to the high structural stability and moderate optical absorption of CsPbI 2 Br, the emergence of this material has led to remarkable efficiency records above 10% and accelerated subsequent studies in the field of all‐inorganic perovskite‐based photovoltaics.…”

“…Concerns about this stability issue have stimulated research motivation for all‐inorganic perovskites. Since 2015, high‐performance cesium lead halide (CLH) perovskite‐based solar cells have begun to be reported 20, 21, 22, 23, 24, 25, 26, 27, 28, 29. Tailored composition and additive studies have led to a high photovoltaic efficiency as well as improved structural stability.…”

Alkali Metal Doping for Improved CH3NH3PbI3 Perovskite Solar Cells

“…and X is a monovalent anion (Cl − , Br − , I − , SCN − etc.) have attracted great attention owing to their superior photoelectronic properties 1, 2, 3, 4, 5. As a type of star material in the photovoltaic field, the performance of perovskite‐based thin film solar cells have gone through tremendous advance, almost caught up with or even gone beyond the efficiency of crystalline silicon, CIGSe (copper–indium–gallium diselenide) and CdTe solar cells only in a few years 1, 6, 7, 8, 9, 10.…”

Фотолюминесценция нанокристаллов перовскитов CsPbX-=SUB=-3-=/SUB=- (X=Cl, Br, I) и твердых растворов на их основе

“…В гибридном перов-ските CH 3 NH 3 PbI 3 позицию A занимает положительно заряженная группа метиламмония CH 3 NH + 3 , B -ион свинца Pb 2+ , X -ион иода I − или, в общем случае, ион другого галогена. Для повышения температурной и химической стабильности структуры органическую группу в позиции A можно заменить на крупный катион, например цезий Cs + [6], перейдя, таким образом, к неорганическому материалу.…”