STAR Lab - Research

Research Areas

Perovskite Photovoltaics

Solar cells based on halide perovskite materials are currently the fastest-growing photovoltaic (PV) technology in research and development. Our work focuses on (1) developing (design and synthesis) low-cost organic and inorganic charge transport layers (CTLs) and (2) understanding their interface with perovskites in terms of crystallization dynamics and charge transport behaviour. For this, we employ device engineering concepts including solution chemistry, optical, electrical, and photoemission spectroscopy to optimize these materials for large-area single-junction perovskite solar cells (1 cm²) as well as silicon-perovskite and organic-perovskite tandem solar cells.

Additionally, we are working on synthesizing and stabilizing all-inorganic perovskite materials for semitransparent and indoor photovoltaic applications (e.g., IoT devices) while improving their thermal stability. We are also exploring lead-free and low-lead (PbSn) low-bandgap (Eg = 1.2 eV) perovskite materials, investigating their degradation pathways, and developing strategies to enhance their overall performance and stability.

We also fabricate perovskite solar cells by focusing on compositional engineering and tuning the energy level alignment with the neighbouring CTL for efficient charge transport with suppressed charge carrier recombination at the interface.

Understanding the crystallization of perovskite on organic charge transport layer

Advanced Functional Materials, 2023, 33, 2305812

Understanding the charge transport properties in between the perovskite and charge transport layer

Advanced Energy Materials, 2023, 13, 2300448

Understanding the degradation pathways and developing strategies to improve the stability.

Energy and Environmental Science, 2025, 18, 1920

Solar RRL, 2021, 5, 2100077

Silicon-Perovskite Tandem Photovoltaics

Silicon-perovskite tandem solar cells have emerged as one of the most promising advancements in photovoltaic technology, offering the potential to surpass the efficiency limits of conventional single-junction silicon solar cells. By integrating a perovskite solar cell as the top absorber and a silicon solar cell as the bottom absorber, this tandem architecture effectively utilizes a broader range of the solar spectrum. The perovskite top cell, with a tunable wide bandgap (~1.65–1.75 eV), efficiently absorbs high-energy photons (blue and green light), while the silicon bottom cell captures lower-energy photons (red and near-infrared light). This reduces thermalization losses and maximizes power conversion efficiency, making tandem solar cells an attractive candidate for next-generation photovoltaics.

Our research focuses on optimizing the perovskite top cell by engineering materials with high efficiency and long-term stability. We investigate various compositions, additives, and interfacial modifications to enhance charge transport, reduce recombination losses, and mitigate ion migration—one of the key degradation mechanisms in perovskite materials. Additionally, we explore advanced passivation strategies, including self-assembled monolayers (SAMs) and defect engineering, to improve interfacial quality and minimize voltage losses.

Scalability and commercial viability are critical aspects of our research. We are working on developing cost-effective, scalable fabrication methods, such as slot-die coating and blade coating, to transition from small-area laboratory cells to large-area tandem modules. Additionally, we focus on encapsulation techniques and environmental stability studies to ensure that these devices can withstand real-world operating conditions, including heat, moisture, and UV exposure. Through these efforts, we aim to bridge the gap between lab-scale efficiency records and real-world commercial applications of silicon-perovskite tandem solar cells.

Silicon-perovskite Tandem Solar Cells

Schematic illustration of silicon-perovskite tandem solar cells

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