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To solve the problem that zinc oxide nanorods (ZnO NRs)-based self-powered ultraviolet (UV) photodetectors cannot obtain both higher responsiveness and shorter response time, P(EDOS-TTh) was prepared using 3,4-ethylenedioxyselenphene (EDOS) and terthiophene (TTh) as copolymers, which modify the ZnO NRs surface, and the ZnO/P(EDOS-TTh) P-N junction self-powered UV device is assembled. The effect of the number of electrochemical polymerization cycles on the UV photodetection performance of ZnO/P(EDOS-TTh) P-N heterojunction was studied by adjusting the number of electrochemical polymerization cycles at the monomer molar ratio of 1:1. Benefiting from the enhanced built-in electric field of the ZnO/P(EDOS-TTh) interface, balancing photogenerated carriers, and charge separation and transport. The results show that the contact between N-type ZnO NRs and P-type P(EDOS-TTh) is best when the number of polymerization cycles is 3, due to the fact that EDOS-TTh and ZnO NRs form excellent P-N heterojunctions with strong internal electric fields, and the devices show good pyroelectric effect and UV photodetection performance. Under 0 V bias and 0.32 mW/cm2 UV irradiation, the responsivity (R) of ZnO/P(EDOS-TTh) reaches 3.31 mA/W, the detectivity (D*) is 7.25 × 1010 Jones, and the response time is significantly shortened. The rise time is 0.086 s, which exhibited excellent photoelectric properties and stability. UV photodetection performance with high sensitivity and fast response time is achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high performance self-powered UV PD was designed based on a sandwich configuration and with p-n junction, which is consisting of ZnO as the bottom n- layer, PEDOS as the top of p-layer, and ZnSe as the insertion layer. • The study suggestion that the ZnSe layer acts a key role in the superior property of the obtained device. • A high detectivity (1.42 × 1011) and a responsivity (5.44 mA/W) values were achieved under low light power (0.32 mW/cm2). • This study presented a new idea to efficiently enhance the properties of the organic–inorganic p-n heterojunction UV PDs. In the present work, a novel self-powered hybrid ultraviolet (UV) photodetector (PD) based on ZnO @ZnSe nanoarrays/poly(3,4-ethylenedioxyselenophene) (PEDOS) was fabricated and systematically investigated. The designed PD is based on a sandwich configuration and with p-n junction, which is consisting of ZnO as the bottom n- layer, PEDOS as the top of p-layer, and ZnSe as the insertion layer. The results of the study on the performances of UV PD under different conditions optical power density shows that the ZnO@ZnSe/PEDOS exhibits excellent detection of UV light, the device achieves the excellent responsivity (R) 5.44 mA/W and high detectivity (D*) 1.42 × 1011 Jones under the weaker optical power density (0.32 mW/cm2). The study concludes with a suggestion that the ZnSe layer acts a key role in the superior property of the obtained device, which is introduction of ZnSe layer between the p-PEDOS and n-ZnO layers reduces band migration and thus effectively enhances carrier transport within them, and demonstrating that the responsivity (R) of ZnO@ZnSe/PEDOS is almost 18 times that of the device without the ZnSe layer (0.3 mA/W). On the other hand, as the p- types PEDOS, which enhances the junction quality by reducing the composite center of the carrier, expanding the depletion region and providing a step energy level between the band edges of ZnO and ZnSe, improving the overall collection of photogenerated carriers. [ABSTRACT FROM AUTHOR]

ZnO NRs-based self-powered ultraviolet (UV) photodetectors (PDs) have gained significant interest from researcher recently, owing to its high stability and optoelectronic performance. However, the slow responding speed and high dark current caused by defects in ZnO NRs limit the application of self-powered UV PDs. Organic conducting polymer poly(3,4-ethylenedioxyselenophene) (PEDOS) has been used as p-type materials, because its good hole transport ability can enable excellent photodetection performances. Here, a self-powered PEDOS/Au NPs-ZnO hybrid UV PD is reported, having a high responsivity of 0.369 mA/W, a favorable detectivity of 1.17 × 1010 Jones as well as fast photo response time (τ rise and τ fall of 0.32 s and 0.44 s) in self-powered mode. In addition, the I ph / I dark ratio of this PD is about 39, and has almost no change after 8 cycles. Comparing with the UV PD without Au NPs (ZnO NRs/PEDOS), the dark current of PEDOS/Au NPs-ZnO UV PD is reduced by 2 times (from 1.52 μA to 0.75 μA) and its photocurrent is increased by 8 times (from 3.79 μA to 29.1 μA). The result shows that p-type PEDOS form p-n heterostructure with ZnO NRs, and the plasmonic effect of Au NPs can enhance response characteristics of the UV PDs. [Display omitted] • A high performance self-powered UV PD was designed based on Au NPs decorated n-type ZnO NRs and p-type PEDOS p-n heterojunction. • The plasma effect of Au NPs on the UV detection performance of PEDOS/Au NPs-ZnO heterojunctions was studied. • The hybrid device exhibits excellent responsivity and detectivity under lower light power (0.32 mW/cm2). • This study presented a new idea to efficiently enhance the properties of the organic-inorganic p-n heterojunction UV PDs. [ABSTRACT FROM AUTHOR]