Broadband infrared photodetection using a narrow bandgap conjugated polymer.

Jarrett H Vella,Kevin S Mayer,Naresh Eedugurala,Tse Nga Ng,Jason D Azoulay,Lifeng Huang

doi:10.1126/sciadv.abg2418

Abstract

Photodetection spanning the short-, mid-, and long-wave infrared (SWIR-LWIR) underpins modern science and technology. Devices using state-of-the-art narrow bandgap semiconductors require complex manufacturing, high costs, and cooling requirements that remain prohibitive for many applications. We report high-performance infrared photodetection from a donor-acceptor conjugated polymer with broadband SWIR-LWIR operation. Electronic correlations within the π-conjugated backbone promote a high-spin ground state, narrow bandgap, long-wavelength absorption, and intrinsic electrical conductivity. These previously unobserved attributes enabled the fabrication of a thin-film photoconductive detector from solution, which demonstrates specific detectivities greater than 2.10 × 109 Jones. These room temperature detectivities closely approach those of cooled epitaxial devices. This work provides a fundamentally new platform for broadly applicable, low-cost, ambient temperature infrared optoelectronics.

Highlights

Alternative materials have long been researched, such as various allotropes of carbon [7], graphene [8], other two- dimensional (2D) materials [9, 10], transition metal dichalcogenides, black arsenic phosphorus (b-AsP) [11], and solution-processable conjugated polymers (CPs), colloidal quantum dots (CQDs), and metal- halide perovskites (MHPs) [12,13,14,15,16,17,18]
The long-wavelength operation of solution-processable materials such as CPs and MHPs is limited to the near IR (NIR), while other colloidal materials such as CQDs progress further into the IR [19]
Solution-processed PbS CQDs operating at 1.3 m show higher specific detectivities (D*) at room temperature than cooled epitaxial devices that results from a large photoconductive gain [20], while ambient temperature MWIR-LWIR operation has been demonstrated using b-AsP ( = 3 to 8.05 m) [11] and PdSe2 [21]

Summary

Introduction

Alternative materials have long been researched, such as various allotropes of carbon [7], graphene [8], other two- dimensional (2D) materials [9, 10], transition metal dichalcogenides, black arsenic phosphorus (b-AsP) [11], and solution-processable conjugated polymers (CPs), colloidal quantum dots (CQDs), and metal- halide perovskites (MHPs) [12,13,14,15,16,17,18]. The long-wavelength operation of solution-processable materials such as CPs and MHPs is limited to the near IR (NIR), while other colloidal materials such as CQDs progress further into the IR [19]. These materials have enabled tremendous advancements that overcome classical photodetection limitations. Solution-processed PbS CQDs operating at 1.3 m show higher specific detectivities (D*) at room temperature than cooled epitaxial devices that results from a large photoconductive gain [20], while ambient temperature MWIR-LWIR operation has been demonstrated using b-AsP ( = 3 to 8.05 m) [11] and PdSe2 (up to 10.6 m) [21]. Cooled epitaxial semiconductors remain the dominant technology throughout the SWIR-LWIR spectral regions

Methods

Results

Conclusion