Stable Ultra-Fast Broad Bandwidth Photodetectors based on α-CsPbI3 Perovskite and NaYF4:Yb,Er Quantum Dots
Photodetectors (PDs), especially response in the infrared region, are highly desirable and have a wide range of applications ranging from cell phones, cameras, home electronics to airplanes and satellites. Herein, we designed and fabricated PDs based on air-stable α-CsPbI3 QDs and up-conversion material (NaYF4:Yb,Er QDs) using a facial low temperature spin-coating method. When α-CsPbI3 QDs is surface-modified using NaYF4:Yb,Er QDs, it extends the optical response to the NIR wavelength to allow broadband application from UV to Visible to NIR (260 nm-1100 nm). The optoelectronic properties and compositional stability of the devices are also studied in detail. As a result, the PDs are capable of broad bandwidth photodetection from deep UV to NIR (260 nm-1100 nm) with good photoresponsivity (R, 1.5 A/W), high on/off ratio (up to 104) and very short rise/decay time (less than 5 ms/5ms). It is found that the photoresponsivity performance is better than all other perovskite QDs based PDs with lateral device structure. Furthermore, the device performance shows very little degradation over the course of 60 days of storage in ambient condition. The combination of remarkable stability, high performance broad bandwidth photodetection, and easy fabrication categorize the QDs as a very promising semiconducting candidate for optoelectronic applications.