Paul van Gerven
14 December 2021

Holst Centre has developed a flexible fingerprint scanner based on metal-halide perovskites – a material class better known for its solar applications. “For the first time, we show that these materials are also very good for light imaging and sensing applications. When combined with display-like transistors, we made a scanner that can capture high-resolution color images as well as biometric fingerprinting,” comments Gerwin Gelinck, CTO TNO at Holst Centre.

Holst perovskite image stack
The perovskite image sensor stack. Credit: Holst Centre

Metal-halide perovskites drew attention for PV applications because of their broad light absorption range, tunable bandwidths, high extinction coefficients, high charge-carrier mobilities and long electron-hole diffusion lengths. In addition, they’re suitable for low-cost, large-area solution processing. These properties are equally useful in photodetection applications.

“Because our imager is very thin, it can be wrapped around round objects. This is for instance advantageous in high-resolution, nail-to-nail biometric fingerprint scanning. Furthermore, we show that it can detect your heartbeat simultaneously, which is another safety feature. We believe that our perovskite image sensors are ideal for integration into everyday objects such as the backside of mobile phones and door handles as part of unobtrusive, secure-access control systems,” says Albert van Breemen, senior researcher TNO at Holst Centre, who led the research.