High‐Performance Polymer Photodetector Using the Non‐Thermal‐and‐Non‐Ultraviolet–Ozone‐Treated SnO2 Interfacial Layer

In organic or perovskite photovoltaic‐type devices, to improve device performance, the thermal and ultraviolet–ozone (UVO) treatments are usually critical for the metal oxide film fabrication by removing the interfacial layer induced defects. However, the defects might play the opposite role in photoconductive photodetectors, where the defect‐induced photogenerated charge accumulation can lead to a tunneling current. Herein, a high‐performance solution‐processed broadband organic photodetector (OPD) in the visible wavelength is realized and characterized by introducing the non‐thermal‐and‐non‐UVO‐treated SnO 2 nanoparticle film between the indium tin oxide (ITO) electrode and the active layer of the poly(3‐hexylthiophene) (P3HT):phenyl‐C61‐butyric‐acid‐methyl‐ester (PC 61 BM) blend. The untreated SnO 2 nanoparticle layer can efficiently block the external charge injection, which considerably reduces the dark current density. Under illumination, the photogenerated charges are accumulated at the interface between the SnO 2 layer and the active layer, and thus contribute a tunneling injection, resulting in a significantly high photocurrent. Therefore, the OPD shows a high performance in every figure of merit: external quantum efficiency (EQE) of 1430%, responsivity of 6.97 A W −1 , detectivity of 2.29 × 10 13 Jones, and −3 dB bandwidth of 2.8 MHz. The solution‐processed high‐performance photodetectors without thermal and UVO treatments are highly compatible with low cost, flexible, and large‐area electronics.