Interpenetrating interfaces for efficient perovskite solar cells with high operational stability and mechanical robustness

Abstract

The perovskite solar cell has emerged rapidly in the field of photovoltaics as it combines the merits of low cost, high efficiency, and excellent mechanical flexibility for versatile applications. However, there are significant concerns regarding its operational stability and mechanical robustness. Most of the previously reported approaches to address these concerns entail separate engineering of perovskite and charge-transporting layers. Herein we present a holistic design of perovskite and charge-transporting layers by synthesizing an interpenetrating perovskite/electron-transporting-layer interface. This interface is reaction-formed between a tin dioxide layer containing excess organic halide and a perovskite layer containing excess lead halide. Perovskite solar cells with such interfaces deliver efficiencies up to 22.2% and 20.1% for rigid and flexible versions, respectively. Long-term (1000 h) operational stability is demonstrated and the flexible devices show high endurance against mechanical-bending (2500 cycles) fatigue. Mechanistic insights into the relationship between the interpenetrating interface structure and performance enhancement are provided based on comprehensive, advanced, microscopic characterizations. This study highlights interface integrity as an important factor for designing efficient, operationally-stable, and mechanically-robust solar cells.

Precursor Engineering of the Electron Transport Layer for Application in High‐Performance Perovskite Solar Cells

“…[35] Although perovskite precursors have proven effective in optimizing the performance of optically active layers, their application in SnO 2 ETLs has been rarely reported in the literature. [41] Herein, we report a facile and effective process for ETL modification through the addition of a perovskite precursor. Initially, two predetermined precursor compositions, specifically MACl and FACl, were introduced into the SnO 2 layers.…”

A Review on Emerging Barrier Materials and Encapsulation Strategies for Flexible Perovskite and Organic Photovoltaics

“…The mechanical durability of OPVs and PSCs has improved remarkably with some unencapsulated devices showing minimal performance losses after thousands of bending cycles. [ 168–175 ] In many cases, these tests are performed in an inert environment to mitigate the extrinsic degradation effects (i.e., moisture and oxygen) mentioned in the previous section. A typical bending apparatus is shown in Figure 6 a, indicating a bending radius of 4 mm.…”

Trifluoromethyl‐Group Bearing, Hydrophobic Bulky Cations as Defect Passivators for Highly Efficient, Stable Perovskite Solar Cells

“…Several innovative strategies, such as compositional engineering, [10] antisolvent engineering, [11] additive engineering, [12,13] interfacial engineering, [14] surface passivation, [15,16] and heat treatment, [17,18] have been proposed to tailor the defects of the perovskite films. The surface passivation approach is particularly effective because the perovskite surface typically accommodates the most defects and grain boundaries.…”