Surface passivation engineering strategy to fully-inorganic cubic CsPbI3 perovskites for high-performance solar cells

Abstract

Owing to inevitable thermal/moisture instability for organic-inorganic hybrid perovskites, pure inorganic perovskite cesium lead halides with both inherent stability and prominent photovoltaic performance have become research hotspots as a promising candidate for commercial perovskite solar cells. However, it is still a serious challenge to synthesize desired cubic cesium lead iodides (CsPbI 3 ) with superior photovoltaic performance for its thermodynamically metastable characteristics. Herein, polymer poly-vinylpyrrolidone (PVP)-induced surface passivation engineering is reported to synthesize extra-long-term stable cubic CsPbI 3 . It is revealed that acylamino groups of PVP induce electron cloud density enhancement on the surface of CsPbI 3 , thus lowering surface energy, conducive to stabilize cubic CsPbI 3 even in micrometer scale. The cubic-CsPbI 3 PSCs exhibit extra-long carrier diffusion length (over 1.5 μm), highest power conversion efficiency of 10.74% and excellent thermal/moisture stability. This result provides important progress towards understanding of phase stability in realization of large-scale preparations of efficient and stable inorganic PSCs.

CsI‐Antisolvent Adduct Formation in All‐Inorganic Metal Halide Perovskites

“…These values correlate well with the relative J SC for each antisolvent, demonstrating that the band edge absorption is mainly limiting the J SC . Although CsPbI 3 device operational stability is outside of the scope of this work, there are many methods used to improve stability which could synergistically be combined with this work to further improve stability …”

Synergy of Hydrophobic Surface Capping and Lattice Contraction for Stable and High‐Efficiency Inorganic CsPbI2Br Perovskite Solar Cells

“…Huang et al used sulfobetaine zwitterions to develop PSCs that exhibited a PCE of 11.4% without efficiency degradation after being exposed to air with ≈85% humidity for over 30 days . Using a polymer additive (polyvinylpyrrolidone), Yin et al prepared CsPbI 3 a PSC with good moisture stability . More recently, inorganic quasi‐2D CsPbX 3 (X = halide) emerged, was systematically studied, and delivered a PCE of 12.4% for a CsPbI 3 PSC with greatly improved stability .…”

A Dopant‐Free Polymeric Hole‐Transporting Material Enabled High Fill Factor Over 81% for Highly Efficient Perovskite Solar Cells

“…However, the negative charges in PBT1-C were mainly concentrated on the carbonyl (CO) groups, which can act as a Lewis base to passivate the under-coordinated Pb atoms. [32,[45][46][47] In order to investigate the charge transfer dynamics from the perovskite to HTMs, steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) were measured by depositing different HTM onto perovskite films. In Figure 2b, the pure PBT1-C exhibited a peak of CO bond at 1660 cm −1 in the FTIR spectrum, however, the blend sample of PBT1-C:PbI 2 showed a blue-shifted peak of 1648 cm −1 .…”