Indoor transition metal dichalcogenide solar cells may reach 36.5% efficiency

New research from Stanford University has investigated the performance limits of transition metal dichalcogenide solar cells for indoor energy harvesting intended for powering internet of things (IoT) devices and sensors. The analysis showed these cells may reach a power conversion efficiency of up to 36.5%.

March 19, 2025 Emiliano Bellini

Image: Stanford University

From pv magazine Global

A group of researchers at Stanford University has investigated the potential of transition metal dichalcogenide (TMD) solar cells for light harvesting in indoor environments and has found that these devices offer the highest potential compared to other cell technologies.

TMDs are two-dimensional materials with remarkable semiconducting properties and high optical absorption coefficients. This makes them suitable for the production of semi-transparent and flexible solar cells with potential applications in aerospace, architecture, electric vehicles, and wearable electronics, where light weight, a high power-per-weight ratio, and flexibility are very desirable.

“Our work evaluates the potential of transition TMD solar cells for powering indoor IoT devices,” the research’s corresponding author, Frederick Nitta, told pv magazine. “It shows that TMD solar cells can outperform commercial indoor photovoltaics under various lighting conditions. Our study highlights that improving material quality and optimizing designs are key to unlocking higher efficiencies. Overall, TMD solar cells could offer a practical, sustainable energy solution for the expanding IoT ecosystem.”

“Transition metal dichalcogenides are layered materials like WSe2 and MoS2, which have high optical absorption, good band gaps, and are rapidly getting ‘good enough’ for such applications, even with some defects still present,” co-author Eric Pop added. “We looked at their fundamental performance limits using a realistic detailed balance model with measured optical properties and several recombination mechanisms, including defects. In most cases, even with materials available today, the TMD thickness to maximize solar cell performance is just 20 to 30 nm.”

In the paper “Transition metal dichalcogenide solar cells for indoor energy harvesting,” published in Device, the research team considered single-junction solar cells made of TMD materials such as molybdenum disulfide (MoS₂), molybdenum diselenide (MoSe₂), tungsten disulfide (WS₂) and tungsten diselenide (WSe₂) at different material qualities and under various indoor lighting conditions.

The scientists used a balance model incorporating measured optical properties as well as radiative, Auger, and Shockley-Read-Hall (SRH) recombination, as well as various indoor light sources, including compact fluorescent lamp (CFL), light-emitting diode (LED), halogen, and low-intensity AM 1.5 G lighting.

“We find that TMD solar cells can outperform existing indoor PV technologies, with power conversion efficiency limits up to 36.5% under fluorescent, 35.6% under LED, 11.2% under halogen, and 27.6% under low-light AM 1.5 G lighting at 500 lux,” the scientists stated. “With today’s material quality, TMD solar cells can achieve up to 23.5% under fluorescent, 23.5% under LED, 5.9% under halogen, and 16.3% under low-light AM 1.5 G lighting at 500 lux.”

They concluded that TMD PV devices have the potential to outperform other commercial indoor photovoltaic technologies. “Future work will need to focus on further refining the electrical and optical designs of TMD solar cells to fully capitalize on their high-efficiency potential and adapt them for broader commercial applications,” they said.

This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.