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Updated: Jun 2, 2026
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Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance
Published on: February 27, 2017
Strategic Modulation of Phenothiazine-Based Self-Assembled Monolayers for Optimized Energy-Level Alignment and
Hung Van Tran1,2, Hyojin Cho3, Min Thein Kyaw4
1Photovoltaic Laboratory, Renewable Energy Institute, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 34125, Republic of Korea.
ACS Applied Materials & Interfaces
|June 1, 2026
Summary
Researchers engineered phenothiazine-based self-assembled monolayers (SAMs) for perovskite solar cells (PSCs). They found a balance between high efficiency and stability, crucial for advancing photovoltaic technology.
Area of Science:
- Materials Science
- Renewable Energy
- Photovoltaics
Background:
- Perovskite solar cells (PSCs) are a promising photovoltaic technology.
- Effective hole-selective contacts are crucial for PSC performance and stability.
- Self-assembled monolayers (SAMs) are commonly used as hole-selective contacts.
Purpose of the Study:
- To engineer phenothiazine-based SAMs with tunable properties for PSCs.
- To investigate the relationship between SAM molecular structure, interfacial energetics, and device performance.
- To identify optimal SAM design principles for high-efficiency and stable PSCs.
Main Methods:
- Systematic engineering of five phenothiazine-based SAMs (MeO- to CN-2EPT) with varied terminal substituents.
- Tuning of molecular dipole moments and highest occupied molecular orbital (HOMO) energy levels.
- Characterization of interfacial energetics, charge extraction efficiency, recombination losses, and device stability.
Main Results:
- Br-2EPT achieved optimal energetic alignment with the perovskite valence band maximum (VBM = -5.68 eV), resulting in the highest power conversion efficiency (PCE) of 19.9% and minimal recombination.
- CN-2EPT exhibited strong defect passivation due to its cyano functionality, leading to excellent long-term stability (97.8% PCE after 100 h, 95% after 70 days).
- CN-2EPT's deeper HOMO energy level created a hole-extraction barrier, limiting fill factor and overall efficiency.
Conclusions:
- A critical trade-off exists between charge extraction efficiency and stability in SAMs for PSCs.
- Interfacial dipole engineering in SAMs is vital for controlling device performance.
- Future hole-selective layer design should combine strong passivating groups with HOMO levels matching the perovskite VBM for optimal efficiency and durability.
