While traditional solar cells are critical for mitigating the worst impacts of climate change, they are often limited by the need for vast outdoor space and aesthetic concerns. However, a team of scientists from National Yang Ming Chiao Tung University (NYCU) in Taiwan has achieved a breakthrough by developing solar cells that efficiently convert indoor lighting into electricity, potentially paving the way for solar panel applications in indoor environments.

These new solar panels can generate power from standard indoor lighting, reducing energy consumption and enabling power generation even on cloudy days. Perovskite solar cells (PeSCs), a lower-cost, higher-efficiency alternative to conventional silicon cells, offer high power conversion efficiency (PCE)—the ratio of energy produced after light reaches the cell—making them ideal for converting low-light conditions into electricity.

In a new paper published in APL Energy, NYCU scientists detailed their novel PeSC design. Building on prior research showing PeSCs can achieve PCE comparable to silicon cells under operation, lead author Chen Fangzhong explained in a press statement: "The most common PeSCs on the market are silicon-based panels. However, PeSCs can be made thin, lightweight, flexible, and even semi-transparent, whereas silicon panels are rigid and heavy, limiting them to flat, durable surfaces."

The team tested the PeSCs with impressive results. Under standard sunlight (~12,000 lux), efficiency reached 12.7%—lower than the 26% of top-performing silicon cells—but under much dimmer 2,000 lux (roughly standard office lighting), PeSC efficiency soared to 38.7%.

To develop the cells, researchers tuned the bandgap of the perovskite composition—the minimum energy required for electrons to jump to a higher energy level. By adjusting molecular ratios in the solution used to form the perovskite layer, they achieved a bandgap optimized for absorbing indoor light, a capability not possible with silicon cells.

Chen Fangzhong stated: "PeSCs offer higher indoor efficiency, meaning photovoltaic products can suit a wider range of user scenarios, including cloudy outdoors, indoor settings, and other low-light environments." The team notes their PeSCs could power small devices in sunlight-inaccessible areas.