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Thursday, 22 Nov 2018

Researchers show perovskite can be an efficient and effective low-cost photodetector

The new perovskite contains only inorganic elements (caesium, lead, iodine and bromine), has been tested in a system for optical communication with not perceivable deterioration after 2,000 hours

LiU - The film in the new perovskite transfers both text and images, rapidly and reliably

15 Oct 2018 | Editor

Researchers at the universities in Linköping and Shenzhen have shown how an inorganic perovskite can be made into a cheap and efficient photodetector that transfers both text and music. The research findings have been published in Advanced Materials.

In the autumn of 2016 Feng Gao, researcher in Biomolecular and Organic Electronics at LiU, was awarded a Starting Grant of Eur 1.5 million from the European Research Council (ERC), intended for research into using perovskites in light-emitting diodes.

According to the Feng Gao perovskites form a completely new family of semiconducting materials that are defined by their crystal structures. They can consist of both organic and inorganic substances. They have good light-emitting properties and are easy to manufacture.

For applications such as light-emitting diodes and efficient solar cells, most research has focused on perovskites that consist of an organic substance (containing carbon and hydrogen), metal, and halogen (fluorine, chlorine, bromine or iodine) ions.

However, when this composition was used in photodetectors, it proved to be too unstable.

The results changed, however, when Chunxiong Bao one of Fen Gao colleagues used the "right" materials, and managed to optimise the manufacturing process and the structure of the film.

The film in the new perovskite contains only inorganic elements (caesium, lead, iodine and bromine), has been tested in a system for optical communication, confirming its ability to transfer both text and images, rapidly and reliably. No perceivable deterioration had been observed after 2,000 hours at room temperature.

The researchers believe this to be an important step because all optical communication requires rapid and reliable photodetectors – materials that capture a light signal and convert it into an electrical signal.

Current optical communication systems use photodetectors made from materials such as silicon and indium gallium arsenide. But these are expensive, partly because they are complicated to manufacture. Moreover, these materials cannot to be used in some new devices, such as mechanically flexible, light-weight or large-area devices.

So many researcher have sought to find lower cost replacement, or at least supplementary, materials for many years, and have looked at, for example, organic semiconductors. However, the charge transport of these has proved to be too slow. A photodetector must be rapid.

"It's a promising material for future rapid optical communication"


"Perovskites of inorganic materials have a huge potential to influence the development of optical communication. These materials have rapid response times, are simple to manufacture, and are extremely stable."

"It's very gratifying that we have already achieved results that are very close to application"


Feng Gao, Senior lecturer LiU

High Performance and Stable All‐Inorganic Metal Halide Perovskite‐Based Photodetectors for Optical Communication Applications

Chunxiong Bao | Jie Yang | Sai Bai | Weidong Xu | Zhibo Yan | Qingyu Xu | Junming Liu | Wenjing Zhang | Feng Gao

Advanced Materials 2018 | DOI 10.1002/adma.201803422

Abstract

Photodetectors are critical parts of an optical communication system for achieving efficient photoelectronic conversion of signals, and the response speed directly determines the bandwidth of the whole system. Metal halide perovskites, an emerging class of low‐cost solution‐processed semiconductors, exhibiting strong optical absorption, low trap states, and high carrier mobility, are widely investigated in photodetection applications. Herein, through optimizing the device engineering and film quality, high‐performance photodetectors based on all‐inorganic cesium lead halide perovskite (CsPbIxBr3–x), which simultaneously possess high sensitivity and fast response, are demonstrated. The optimized devices processed from CsPbIBr2 perovskite show a practically measured detectable limit of about 21.5 pW cm−2 and a fast response time of 20 ns, which are both among the highest reported device performance of perovskite‐based photodetectors. Moreover, the photodetectors exhibit outstanding long‐term environmental stability, with negligible degradation of the photoresponse property after 2000 h under ambient conditions. In addition, the resulting perovskite photodetector is successfully integrated into an optical communication system and its applications as an optical signal receiver on transmitting text and audio signals is demonstrated. The results suggest that all‐inorganic metal halide perovskite‐based photodetectors have great application potential for optical communication.

www.liu.se/en/research/laboratory-of-organic-electronics   

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