Novel Interfacial Engineering Achieves 21.34% Efficiency and Superior Defect Passivation in Inverted Perovskite Solar Cells

September 6, 2026

ACS Publications USA

Overview

A new interfacial engineering strategy has been developed to radically improve the performance of inverted perovskite solar cells (IPSCs) at the NiOX/perovskite interface. By incorporating phenethylammonium bromide (PEABr) into an aluminum oxide (Al2O3) matrix, a multifunctional composite interlayer was constructed, simultaneously enabling defect passivation and energy level alignment optimization. This innovative approach allowed IPSCs to achieve a peak power conversion efficiency of 21.34%, facilitating concurrent control over interfacial chemical defects and electronic properties.

In Depth

Key Findings

A groundbreaking interfacial engineering strategy has been developed to significantly enhance the performance of inverted perovskite solar cells (IPSCs), specifically targeting the NiOX/perovskite interface. In this study, a multifunctional composite interlayer was meticulously constructed by incorporating phenethylammonium bromide (PEABr) into a mesoporous aluminum oxide (Al2O3) matrix. This interlayer concurrently achieved two critical functions: defect passivation and optimization of energy level alignment. As a result of this synergistic approach, IPSCs demonstrated a high power conversion efficiency of 21.34%, unequivocally proving the ability to precisely control both the chemical defects and electronic properties at the interface.

Technical & Clinical Details

The efficiency of IPSCs heavily relies on the quality of the interface between the electron transport layer (NiOX) and the perovskite active layer. Defects at this interface act as non-radiative recombination centers, significantly degrading device performance. The developed PEABr and Al2O3 composite interlayer effectively passivates defect sites by forming a quasi-2D/3D perovskite heterostructure at the interface with PEABr. The long-chain alkylammonium cation of PEABr passivates surface defects in the perovskite crystal (particularly uncoordinated lead ions and halide vacancies), suppressing non-radiative recombination of charge carriers. Simultaneously, the Al2O3 matrix optimizes electron transport pathways and improves energy level alignment, thereby enhancing charge extraction efficiency. This synergy strengthens the internal electric field and extends carrier lifetime, leading to improved open-circuit voltage (Voc) and fill factor (FF), ultimately achieving the high efficiency of 21.34%.

Background & Context

Research and development in perovskite solar cells are rapidly advancing in both efficiency and stability, yet controlling interfacial defects remains a critical determinant of device performance. Inverted IPSCs, in particular, attract attention due to specific advantages such as low-temperature processing and adaptability to flexible substrates, but interfacial defects with hole transport layers like NiOX have been a bottleneck for efficiency improvement. The multifunctional composite interlayer proposed in this study offers an effective solution to this interfacial problem, providing new design guidelines for enhancing the overall efficiency and reliability of perovskite solar cells. This marks a crucial step in accelerating the commercialization of next-generation solar cells.

Strategic Significance & Outlook

This interfacial engineering strategy paves a significant path for further performance enhancement and long-term stability assurance in IPSCs. In the future, by further optimizing the composition and structure of this composite interlayer, achieving conversion efficiencies of 25% or more becomes a tangible goal. This technology is also compatible with large-scale production processes; combining it with manufacturing techniques such as slot-die coating and inkjet printing could expand the potential for low-cost, high-efficiency IPSC manufacturing. The evolution of interfacial control technology is expected to boost the commercial competitiveness of perovskite solar cells and accelerate their application in diverse fields, including building-integrated photovoltaics (BIPV), flexible electronics, and transparent solar cells. This research lays an important foundation for perovskite solar cells to realize their full potential as a sustainable energy source.

Source: https://pubs.acs.org/aamick/article/doi/10.1021/acsami.6c13869/5399041/Defect-Passivation-of-Mesoporous-Al2O3-Based

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