Ultrasensitive flexible broadband photodetectors achieving pA scale dark current

Xiao Luo,Feiyu Zhao,Lili Du,Feiping Lu,Yingquan Peng,Ying Wang,Kun Xu,Wenli Lv

doi:10.1038/s41528-017-0005-x

Abstract

Organolead halide perovskite is a newly emerging low-cost, solution-processable material with a broadband absorption from the ultraviolet (UV) to visible (Vis) region, which has attracted a great deal of interest in high-performance optoelectronic devices. However, some practicable applications need a cover of UV–Vis–NIR region for photoelectric conversion, a task that remains a significant challenge for further extending the absorption toward the near-infrared radiation (NIR) region. Here, to the best of our knowledge, we prove for the first time an ultrasensitive flexible broadband photodetector based on porous organolead perovskite-phthalocyanine heterostructure, which combines the synergetic properties of high UV–Vis absorbance of perovskite with enhanced NIR absorption for triclinic lead phthalocyanine. The photosensitivity of the as-prepared devices reaches up to 104 at a low intensity of 10 mW cm−2, which is among the largest values reported for broadband photodetectors. Significantly, performed at room temperature, the device achieves a pA scale dark current along with an ultrafast response speed of less than 0.6 ms for as-adopted full spectra. Our results provide an easy and promising route to develop low-cost, flexible and highly sensitive UV–Vis–NIR photodetectors.

Highlights

Solar energy, mostly spread over visible (Vis) to near-infrared (NIR) region, shows enormous potential in the energy market because of its essentially unlimited supply and renewable, cheap and clean nature.[1, 2] Currently, light detecting and harvesting are two noteworthy photoelectric-conversion processes for exploiting the encouraging solar energy
Device characterizations Figure 1a displays the three-dimensional scheme of PbPc/MAPbI3 − xClx heterostructured photodetector and the corresponding molecular structure of as-adopted materials, respectively
The absorption spectrum of PbPc/MAPbI3 − xClx film further corroborates the result of broadband absorption above, coming to be promising for the fabrication of a UV–Vis–NIR photodetector

Summary

Introduction

Mostly spread over visible (Vis) to near-infrared (NIR) region, shows enormous potential in the energy market because of its essentially unlimited supply and renewable, cheap and clean nature.[1, 2] Currently, light detecting and harvesting are two noteworthy photoelectric-conversion processes for exploiting the encouraging solar energy. Silicon photodetectors are mainly used to sense the Vis/NIR light, while silicon carbide-based devices are ordinarily selected for UV sensing.[11, 12] Especially, some IR photodetectors based on narrow-bandgap semiconductors (such as InGaAs)[13] must be cooled to utilize due to the abundant intrinsic thermal charge carriers (i.e., larger dark current), complicating the routine use of devices. It is urgently desired to obtain a facile and cost-effective UV–Vis–NIR photodetector, achieving room-temperature operational photoelectricconversion

Methods

Results

Conclusion