A novel lead-free, eco-friendly photodetector with self-powered operation that delivers strong and stable performance can be useful for consumer electronics, industrial monitoring, security systems, and biomedical imaging.

Modern cameras, environmental sensors, and smart wearables rely on photodetectors, which are devices that convert light into electrical signals. Many high-performance versions currently utilise lead-based perovskites, which raise toxicity concerns and degrade easily in real-world conditions.

Addressing this challenge, researchers at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI, Hyderabad), an autonomous institute of Department of Science and Technology (DST), in collaboration with IIT Hyderabad, have developed a lead-free, eco-friendly photodetector based on the double perovskite Cs₂AgBiBr₆ that delivers strong and stable performance.

Unlike conventional designs that rely on costly metal contacts and additional hole-transport layers, which often necessitate the use of gloveboxes or vacuum fabrication tools, this device is Hole Transport Material (HTM) -free, utilises low-cost carbon electrodes, and is fabricated entirely at room temperature using a simple one-step coating method. The device architecture naturally supports efficient charge separation, enabling self-powered operation without any external voltage.

The Cs₂AgBiBr₆ photodetector exhibits a strong response to visible light and demonstrates excellent reliability under practical operating conditions. As shown in the figure, the device exhibits consistent ON and OFF switching behaviour and retains more than 90% of its performance even after 60 days of storage. These measurements were conducted under ambient room conditions (25-35 °C and 35-50% relative humidity). The close overlap of the performance curves before and after 60 days confirms its long-term environmental stability.

The combination of a lead-free material system, simple ambient-processed fabrication, low-cost components, and strong operational stability makes this technology highly attractive for consumer electronics, industrial monitoring, security systems, and biomedical imaging. It also aligns with India's goals in sustainable materials, green manufacturing, and achieving self-reliance in next-generation electronics.

Fig:   Schematic of the ecofriendly photodetector devices subjected to various accelerated tests, which validated its stability (left panel). Comparison of Photo-response of as-fabricated photodetector device and 60-days aged photodetector device (right panel).

This work was supported by the Department of Science and Technology (DST), Government of India, and has been published in Solar Energy (Elsevier) entitled, “Ambient-processed lead-free Cs₂AgBiBr₆ photodetector with long-term environmental stability and self-powered operation.”

Publication link: https://doi.org/10.1016/j.solener.2024.112989

****

NKR/FK

(Release ID: 2222632) Visitor Counter : 168