A flexible, rapid response, hybrid inorganic–organic SnSe2–PEDOT:PSS bulk heterojunction based high-performance broadband photodetector

Abstract

Photodetectors based on inorganic semiconductors demonstrate superior responsivity, but their high thermal budget fabrication process is a serious impediment for emerging applications. Hybrid photodetectors based on organic–inorganic heterojunctions synergistically offer the solution-processability and tunability of organic semiconductors, along with the superior absorption coefficient and transport properties of inorganic materials. In this work, a broadband photodetector based on a bulk-heterojunction of hybrid organic-PEDOT:PSS/inorganic-SnSe₂ and a subsequent vertical junction on flexible ITO-coated-PET is demonstrated. SnSe₂ nanoflakes, synthesized via a facile hydrothermal method, exhibit absorption in both the visible and NIR spectra, and are made into a bulk heterojunction (BHJ) with PEDOT:PSS. The ITO layer exhibits absorption in the UV spectra, onto which the SnSe₂–PEDOT:PSS bulk-heterojunction composite is deposited to form a vertical junction. The broadband photodetector exhibits quick response times of 16 ms, 221 ms and 274 ms and superior responsivities of 0.72 A W⁻¹, 0.67 A W⁻¹ and 0.69 A W⁻¹ in the UV, Vis and NIR spectra, respectively. This superior responsivity of the photodetector is related to the enhanced interfacial area between SnSe₂–PEDOT:PSS in the bulk-heterojunction, which leads to efficient electron–hole pair separation. Furthermore, the device is subjected to multiple bending cycles (∼3000) and minimal deviation in responsivity is observed. The facile and low-cost approach demonstrated in this work finds potential applications in novel flexible opto-electronic devices.