Broadband organic phototransistor with high photoresponse from ultraviolet to near-infrared realized via synergistic effect of trilayer heterostructure

Abstract

Broadband photodetectors have attracted tremendous attention in recent years because of their extensive industrial and scientific applications for optoelectronic circuits. However, up until now, developing organic phototransistors with a high photoresponse over the broadband spectrum still remains a great challenge due to the lack of broad spectral photosensitive materials. Herein, we report a high-performance broadband phototransistor by adopting an all-organic trilayer heterostructure as an active structure containing three small organic molecules with mutual-complementary photoabsorption spectra. Utilizing the synergistic effect of the high mobility of a fullerene (C₆₀) channel and strong complementary photoabsorption of a C₆₀/3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)/tin phthalocyanine (SnPc) trilayer heterostructure, a broad high photoresponse from the ultraviolet-visible to the near-infrared region was realized. The photoresponsivity (R), external quantum efficiency (EQE), specific detectivity (D*), and response time reached up to 56.88 A W⁻¹, 15 704%, 9.15 × 10¹² Jones, and <0.5 ms at an incident light intensity of 2 μW mm⁻², respectively, and the photosensitivity (P_max) to 6.39 × 10⁵ at a light intensity of 150 μW mm⁻², most of which are comparable or even surpass the values achieved by commercial silicon, germanium, and indium gallium arsenide photodetectors, as well as many of inorganic and organic photodetectors reported recently. This synergistic strategy opens up a promising avenue for constructing high-performance all-organic photodetectors with a superior broadband response.