Meso-Superstructured Perovskite Solar Cells: Revealing the Role of the Mesoporous Layer

Abstract

While perovskite solar cells (PSCs) have been developed with different device architectures, mesoporous devices have provided the highest power conversion efficiencies. In this work, the working mechanism of both positive-intrinsic-negative (p-i-n) and negative-intrinsic-positive (n-i-p) meso-superstructured (MSSC) PSCs, which include a thin interlayer of porous alumina at the bottom electrode, is explored. Interestingly, for both p-i-n and n-i-p architecture, the mesoporous configuration was more efficient than its planar counterpart. For MSSC SnO 2 -based n-i-p devices, that result was primarily due to an increase in V oc and J sc , resulting from improved band alignment and filling of the electron trap states (n-doping at the SnO 2 /perovskite interface), which led to devices with 21.0% efficiency and 20.3% stabilized power output (SPO). Although MSSC NiO x -based p-i-n meso-superstructured devices were less efficient due to lower V oc , a slightly higher J sc and fill factor improvement was achieved by the Al 2 O 3 mesoporous layer, resulting in devices with 16.9% efficiency. Importantly, the electronic nature of the perovskite is dependent upon its physical confinement within a mesoporous scaffold. Therefore, either p-or n-type semiconductor/perovskite interfaces can be engineered by selectively modifying the semiconductor behavior with the introduction of an insulating mesoporous scaffold interlayer.

Interfacial charge-transfer doping of metal halide perovskites for high performance photovoltaics

“…The decrease in conductivity which occurs at the highest concentration could be due to two factors: increased cluster formation of the dopant on the surface, which may result in increased recombination, with clusters of unreacted dopant acting as trapping sites, or through making the perovskite material too strongly p-type, which has been shown to result in decreased carrier diffusion lengths, through reducing carrier lifetime. 52 Based on both the size of the dopant molecule, as well as the relatively modest change in the dark conductivity, we can presume that the dopant molecules primarily remain on the surface of the perovskite film, and hence, produce a surface doping effect whereby only the perovskite surface effectively becomes more p-type. S3c is approximately 0.67 eV.…”

Elucidating the Role of a Tetrafluoroborate‐Based Ionic Liquid at the n‐Type Oxide/Perovskite Interface

“…These results are consistent with the observation by Ramirez et al, who have demonstrated that the doping character of the perovskite has a strong influence on its optoelectronic properties. [54] At this point it is worth summarizing the effects of the IL on the substrate and on the perovskite. [54] At this point it is worth summarizing the effects of the IL on the substrate and on the perovskite.…”

Oxidative Passivation of Metal Halide Perovskites

“…This perovskite composition has also proved to be more stable in thin-film solar cells with reported device efficiencies that surpass 20%. 32,33 First, we use PL spectroscopy to investigate the effects of the H 2 O 2 post-treatments on the optoelectronic properties of the perovskite films. In Figures 1A and 1B, we show steady-state and time-resolved PL measurements of thin films of FA 0.83 Cs 0.17 Pb(I 0.83 Br 0.17 ) 3 treated via the wet method.…”