IIT Bombay Develops 4T Silicon-Perovskite Tandem Solar Cell with 26 Percent Efficiency

Researchers at IIT Bombay’s National Centre for Photovoltaic Research and Education (NCPRE) have successfully fabricated India’s first 4T silicon-perovskite tandem solar cell, achieving an efficiency of over 26 percent.

This breakthrough addresses stability issues in perovskite solar cells (PSCs) while offering lower production costs and higher energy conversion. Perovskite solar cells have drawn significant interest due to their cost-effectiveness and high efficiency. However, they degrade faster than conventional silicon cells when exposed to heat, light, or voltage over extended periods.

To overcome this, IITB scientists combined a semi-transparent perovskite solar cell with a silicon-based Passivated Emitter and Rear Contact (PERC) solar cell in a tandem structure. This configuration enhances efficiency, stability, and long-term performance while reducing the levelized cost of energy (LCOE).

The semi-transparent perovskite layer allows near-infrared light to pass through, maximizing energy absorption. The team recorded a high power conversion efficiency (PCE) of 17.1 percent for a small-area PSC and 16 percent for a larger-area version. By layering this perovskite cell onto a commercially available silicon solar cell, they significantly improved performance, achieving over 26 percent efficiency for the tandem device.

A 4T tandem device features four terminals, with two assigned to each layer of the tandem structure. This design enables accurate performance measurement while simultaneously enhancing the solar cell’s overall efficiency and longevity. Unlike standalone PSCs, which degrade rapidly, the 4T tandem setup ensures better durability. Even if the top perovskite layer deteriorates, it can be easily replaced without affecting the silicon base, extending the lifespan of the device. The four-terminal (4T) architecture allows independent optimisation of both layers, enhancing overall efficiency and enabling precise performance measurements.

Professor Dinesh Kabra of IIT Bombay highlighted that while perovskite solar cells offer high power conversion efficiency and lower production costs, they have historically faced stability issues. However, IITB’s new 4T silicon-perovskite tandem solar cell demonstrates remarkable stability under dark and continuous heating conditions, making it a breakthrough in solar technology.

This innovation has significant implications for India’s renewable energy ambitions. As global adoption of solar power increases, tandem solar cells, particularly silicon-perovskite hybrids, could revolutionize the industry by offering efficient, cost-effective, and stable solutions for large-scale deployment.