High‐Performance Organic Photodetectors Using SnO2 as Interfacial Layer with Optimal Thickness

A photodiode‐type photodetector with bulk heterojunction is built with an ITO/SnO 2 /P3HT:PC 61 BM/MoO 3 /Al structure. By evaluating SnO 2 interfacial layer thicknesses of 15, 19, 22, 26, and 29 nm, the effect of thickness on the photodetector response is investigated. The results show that the carrier extraction can reach saturation at −1 V. In addition, the device with interlayer thickness of 22 nm achieves the lowest dark current density (1.6 × 10 −6 A cm −2 ), highest specific detectivity (1.3 × 10 11 Jones), widest linear dynamic range (LDR, 43.7 dB), and fastest response (raising/falling time of 1.81/2.22 μs). Hence, the performance of the organic photodetectors can be greatly improved by adopting the proper thickness of the SnO 2 interfacial layer.