Spontaneously Self‐Assembly of a 2D/3D Heterostructure Enhances the Efficiency and Stability in Printed Perovskite Solar Cells

Abstract

As perovskite solar cells (PSCs) are highly efficient, demonstration of high‐performance printed devices becomes important. 2D/3D heterostructures have recently emerged as an attractive way to relieving the film inhomogeneity and instability in perovskite devices. In this work, a 2D/3D ensemble with 2D perovskites self‐assembled atop 3D methylammonium lead triiodide (MAPbI3) via a one‐step printing process is shown. A clean and flat interface is observed in the 2D/3D bilayer heterostructure for the first time. The 2D perovskite capping layer significantly suppresses nonradiative charge recombination, resulting in a marked increase in open‐circuit voltage (VOC) of the devices by up to 100 mV. An ultrahigh VOC of 1.20 V is achieved for MAPbI3 PSCs, corresponding to 91% of the Shockley–Queisser limit. Moreover, notable enhancement in light, thermal, and moisture stability is obtained as a result of the protective barrier of the 2D perovskites. These results suggest a viable approach for scalable fabrication of highly efficient perovskite solar cells with enhanced environmental stability.

Fabrication Strategy for Efficient 2D/3D Perovskite Solar Cells Enabled by Diffusion Passivation and Strain Compensation

“…[ 17,18 ] Therefore, lattice matching is considered to be one of the primary advantages of 2D/3D perovskites heterostructures. [ 19,20 ] The unit cell parameters of PEA 2 PbI 4 ( a = b = 8.74 Å, c = 33.00 Å) have a better structure match with MAPbI 3 ( a = b = 8.87 Å, c = 12.52 Å) [ 21 ] than the commonly used charge transport materials, such as SnO 2 ( a = b = 4.73 Å, c = 3.18 Å) [ 22 ] and TiO 2 ( a = 18.92 Å, b = 30.72 Å). [ 23 ] However, the understanding of residual strain and their effects on 2D/3D perovskites heterostructure is still limited.…”

Hydrophobic 2D Perovskite‐Modified Layer with Polyfunctional Groups for Enhanced Performance and High Moisture Stability of Perovskite Solar Cells

“…The ─SH with a lone pair of electrons in sulfur atom could coordinate with Pb 2þ at the perovskite surface, thus significantly enhancing the anchoring strength. [33] The high affinity of the organic molecule CME toward binding to the inorganic framework PbI 6 could improve the inherent moisture stability. [34] To better understand the influence of CME on perovskite morphology, we measured the scanning electron microscope (SEM) images of pristine and CME films with different concentrations.…”

“…Hu et al incorporated S-benzyl-L-cysteine with amine and carboxyl groups to the 2D/3D heterostructure perovskite and impressively obtained high-quality PSCs. [30] Nevertheless, the interaction between passivators with undercoordinated ions is quite week, resulting in the fact that passivation effect is not very stable. [31,32] The passivation ability of the 2D perovskite layers can been improved by introducing new types of polyfunctional groups.…”

Tailoring organic bulk-heterojunction for charge extraction and spectral absorption in CsPbBr3 perovskite solar cells

“…Fig. S4 presents the TRPL plots and the corresponding carrier decay lifetimes (Table S1) The longer PL lifetime means suppressed charge nonradiative recombination by setting BHJ layer and indicates the small molecules or polymers in the BHJ film can effectively reduce the defect, which can be also cross-checked by the blue-shift of the PL peak [43,44]. The mechanism behind this phenomenon is mainly attributed to the strong interaction between -C=O group in PCBM and the unsaturated Pb atom in the perovskite, which will be discussed in the following part.…”