Inverted ternary OPD based on PEIE

This paper proposes an inverted ternary organic photodetector (OPD), whose structure is ITO/PEIE/PC61BM/P3HT:PCPDTBT/MoO3 /Al. The use of PEIE as the cathode buffer layer avoids the influence of acidic PEDOT:PSS on the surface and life of the conventional device . The preparation of the ternary active layer ensures the photoelectric characteristics of the device in the visible-infrared broad spectrum range. In this experiment, the effect of PEIE thickness on the working mode of the device was studied by changing the concentration of the spin-coated PEIE solution. Finally, when the solution of PEIE is less than 0.45wt%, the device works in the diode mode, on the contrary, it works in the photoconductive mode. And under 550nm illumination (optical power 4.02mW/cm2) , the device achieves a responsivity of 1.64A/W and an external quantum efficiency of 370%.

Effective film surface treatment for improving external quantum efficiency of photomultiplication type organic photodetector

A simple yet effective method based on methanol treatment is proposed to enhance the external quantum efficiency (EQE) of the photomultiplication type organic photodetector with a structure of Glass/ITO/PEDOT:PSS/P3H:PC71BM (100:1, wt./wt.)/Al. By modifying the PEDOT:PSS film surface with methanol, the EQE of photodetector significantly improved within a broad wavelength range of 300–700 nm. The maximum EQE of 25300% occurs at the wavelength of 350 nm in the methanol-treated device under −9 V bias, which more than doubles that (11500%) of the device without treatment. In addition, as a result of the methanol treatment, the detectivity of the device improved from 3.72 × 1012 to 7.24 × 1012 Jones at −9 V under 350 nm light illumination. The large improvement is attributed to the fact that the methanol treatment can improve the electrical performance of the PEDOT:PSS by removing the insulator PSS within the film and also result in PC71BM aggregations in the active layer. The latter can enhance the tunneling hole injection by the intensified energy-level bending, which is induced by both the trapped electrons in these aggregations and accumulated ones near Al electrode. As a result, the modification of both the PEDOT:PSS layer and the active layer increases the response current, resulting in the EQE improvement.

Improving the Sensitivity of an Organic Photodetector by Adding a Polar Solvent to the Hole-Transport Layer for Indirect X-ray Detection

In this work, we investigated how the performance enhancement of an organic X-ray detector was improved by adding a dimethyl sulfoxide (DMSO) polar solvent to poly(3, 4-ethylene dioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) hole-transport layer. The changes in the properties, such as surface roughness, chemical structure, sheet resistance, and absorbance, of the PEDOT:PSS film caused by the DMSO treatment were examined. The application of DMSO treatment lowered the resistance of the PEDOT:PSS film because of the removal of PSS and the chemical structure change after DMSO treatment, and thus the transport of light-induced carriers was increased. The organic detector treated with 10 vol% DMSO showed the highest collected current density (CCD) of 357.42 nA/cm2 and highest sensitivity of 2.58 mA/Gy ·cm2, which were 31.88% and 32.31% higher than the CCD and sensitivity of the detector without DMSO treatment.