High‐Performance, Room Temperature, Ultra‐Broadband Photodetectors Based on Air‐Stable PdSe2

Photodetection over a broad spectral range is crucial for optoelectronic applications such as sensing, imaging, and communication. Herein, a high‐performance ultra‐broadband photodetector based on PdSe2 with unique pentagonal atomic structure is reported. The photodetector responds from visible to mid‐infrared range (up to ≈4.05 µm), and operates stably in ambient and at room temperature. It promises improved applications compared to conventional mid‐infrared photodetectors. The highest responsivity and external quantum efficiency achieved are 708 A W−1 and 82 700%, respectively, at the wavelength of 1064 nm. Efficient optical absorption beyond 8 µm is observed, indicating that the photodetection range can extend to longer than 4.05 µm. Owing to the low crystalline symmetry of layered PdSe2, anisotropic properties of the photodetectors are observed. This emerging material shows potential for future infrared optoelectronics and novel devices in which anisotropic properties are desirable. Ultra‐broadband photodetectors based on noble transition metal dichalcogenide, PdSe2, with unique pentagonal atomic structure are demonstrated. Devices respond from visible to mid‐infrared (up to ≈4.05 µm) and efficient absorption beyond 8 µm is observed. The maximum photoresponsivity and photogain are 708 A W−1 and 82 700%, respectively. Anisotropic photoresponse is also observed.