1,8‐Octanediamine Dihydroiodide‐Mediated Grain Boundary and Interface Passivation in Two‐Step‐Processed Perovskite Solar Cells

Abstract

Two‐step‐processed perovskite solar cells show superior reproducibility in terms of stepwise crystallization management. However, the device performance is limited due to the buried‐interface defects that are highly dependent on the diffusion process of organic salts into PbI2. Herein, 1,8‐octanediamine dihydroiodide (ODADI) is adopted to develop an alkylammonium predeposition strategy for the high‐quality perovskite film. It is found that the pre‐deposited ODADI layer not only facilitates the diffusion of organic salts via interaction with PbI2, but also passivates the buried‐interface defects, resulting in a perovskite film with low defect density, high crystallinity, and superior electronic properties. Consequently, the fabricated devices deliver a significant enhancement on power conversion efficiency (PCE) from 19.87 to 22.07%. In addition, a superior long‐term stability in glovebox atmosphere, maintaining 96% of the initial PCE after 1000 h, is demonstrated.

Predeposited Multifunctional Carbon Nanotube:SnO2 on the PbI2 Film for Efficient and Stable Two‐Step‐Processed Perovskite Solar Cells

“…A similar phenomenon can also be observed in large-scale films (Figure S1d,e, Supporting Information), which indicates that the crystallinity and compactness of the perovskite film were improved, followed by fewer defects on the perovskite crystal surface and grain boundary. [27] Atomic force microscope (AFM) characterization further confirmed these results, as shown in Figure 3d,e. The films containing CNT:SnO 2 exhibit lower surface roughness and larger grain size.…”

“…In addition, there are two small peaks before the characteristic peak in the Pb 4 f spectrum (Figure S2b, Supporting Information), which have been attributed to a kind of nonradiative recombination center deteriorating the device performance. [ 27 ] Obviously, the peak intensity decreased after the incorporation of CNT:SnO 2 , indicating that CNT:SnO 2 suppressed the nonradiative charge recombination in perovskite film.…”

Molecularly Tailored Surface Defect Modifier for Efficient and Stable Perovskite Solar Cells

“…[50] According to previous reports, a high potential represents a low work function, and the results of KPFM are consistent with UPS measurements. [51,52] Using TMBAI to modify the HTL/Perovskite interface can adjust the work function of perovskite and enhance the photogenerated hole extraction and transport properties of HTL, which is crucial for improving the device performance of PSCs. [53] To investigate the effect of TMBAI on the performance of complete PSCs devices, devices with/without TMBAI were fabricated for the comparative study.…”

Defect Management and Ion Infiltration Barrier Enable High-Performance Perovskite Solar Cells

“…As previously discussed (Figure c), this enhancement is mainly attributed to PHPA’s ability to modulate crystallization and passivate defects. Besides, the PHPA+PFOA device demonstrates a more significant improvement in device efficiency compared to PHPA device, delivering a champion PCE as high as 25.1% with a significant V oc of 1.189 V. This impressive enhancement on device efficiency and V oc is mainly attributed to the PFOA modification which can further passivate the surface defects of the perovskite film, as supported by the PL and TRPL analysis (Figure S14). Figure b presents the external quantum efficiency (EQE) curves of the devices.…”