Why in the News?

Researchers at IIT Bombay have developed a high efficiency tandem solar cell with power conversion efficiency of approximately 30 per cent compared with around 20 per cent now.

What’s in Today’s Article?

• About the Innovation (Background, Tandem Solar Cell Tech, Potential Impact, Strategic Importance, etc.)

Introduction

• In a landmark development for India’s renewable energy landscape, IIT Bombay has unveiled a next-generation solar cell technology that offers a substantial leap in both efficiency and affordability.
• The innovation, developed at the National Centre for Photovoltaic Research & Education (NCPRE), employs a tandem structure combining perovskite and silicon materials to create a solar cell that could significantly boost India’s clean energy capacity.
  • Perovskite materials are a diverse class of compounds, characterized by a specific crystal structure similar to the mineral calcium titanate (CaTiO3).
  • This structure, often represented by the formula ABX3, is responsible for their unique properties and applications in various fields, particularly in solar cells and other optoelectronic devices.
• With efficiency rates projected at nearly 30%, compared to the existing 20% in conventional silicon cells, this innovation may reduce the cost of solar power to as low as ₹1 per kilowatt-hour (kWh), making solar energy more accessible and sustainable.

Tandem Solar Cell Technology: A Game-Changer

• The newly developed technology is based on a four-terminal (4T) tandem solar cell design.
• In this architecture, a semi-transparent halide perovskite-based top cell is layered over a silicon-based bottom cell, allowing both to function independently.
• This configuration enhances power conversion efficiency and operational stability.
  • Perovskite Advantage: Halide perovskites are recognized for their exceptional light absorption and low manufacturing cost.
    • IIT Bombay's breakthrough also addresses perovskite’s major drawback, its short lifespan, by extending its durability to around 10 years.
  • Operational Durability: The tandem cell remains stable under heat and low-light conditions, improving its viability across diverse Indian climates.
• The research team explained that this solution not only improves energy output but also enables better land-use efficiency, which is critical for a densely populated country like India.

Potential Impact on Solar Energy Ecosystem

• Enhanced Efficiency & Cost Reduction
  • Boosts power conversion efficiency by 25-30% over conventional technologies.
  • Expected to bring down the cost of solar electricity to nearly ₹1 per kWh, a steep drop from the current ₹2.5-4 per unit.
• Reduced Import Dependence
  • Currently, India heavily relies on China for solar-grade raw materials. Perovskite materials, which can be synthesized using locally available chemicals, will help reduce this dependency.
• Support for Green Hydrogen Initiatives
  • The Maharashtra government and IIT Bombay are collaborating on a clean energy hub in Uran, with a focus on green hydrogen production using this new solar technology.
  • High-efficiency tandem cells are vital for the photoelectrochemical splitting of water to produce hydrogen sustainably.

Commercialization and Industrial Collaboration

• The technology is being scaled up through ART-PV India Pvt. Ltd., a start-up incubated at IIT Bombay’s Society for Innovation and Entrepreneurship (SINE).
• It aims to provide a commercial wafer-size solution for tandem cells by December 2027 using indigenous manufacturing tools.
• Public Sector Engagement: The state government has directed MAHAGENCO, its power generation utility, to evaluate deployment and commercialization opportunities for the technology.

Strategic Importance for India’s Energy Future

• This development aligns with India’s long-term goals under the National Solar Mission and its Net Zero 2070
• As land scarcity and material imports continue to challenge India’s renewable energy goals, high-efficiency indigenous solutions like this are critical to scaling up solar energy without proportionate increases in land or capital costs.
• Additionally, the ability to integrate these cells into rooftops, vehicles (Vehicle-integrated photovoltaics (VIPV)), and buildings (BIPV) enhances their application versatility, pushing India closer to a decentralized and resilient energy grid.