Light sources and detectors are key components of countless technological devices on the market today. For instance, light emitting diodes (LEDs) are often used as a source of light in displays and other technologies, while photodiodes are used to detect light in sensors, imaging and fiber optic communication tools.
Existing light sources and detectors comprise two distinct types of devices with markedly different functions. Developing a device that can both generate and detect light, however, could enable the design of smaller and smarter technologies.
Researchers at Link?ping University in Sweden, Shenzhen University and several other universities in China have recently fabricated an efficient diode capable of both emitting and detecting light. This new device, presented in a paper published in Nature Electronics, was built using a solution-processed perovskite material.
"If we had a dual-functional device that could efficiently emit and detect light, we could use a single device to do the work that typically requires two conventional devices," Feng Gao, principal investigator on the study, told TechXplore. "This could not only reduce how much devices cost, but also facilitate the integration of light sources and detectors in optoelectronic chips."
In a previous study featured in Nature Photonics, Gao and his colleagues identified a mechanism known as the 'passivation effect' in perovskite films, which are emerging materials used to build LEDs. They then designed an efficient passivator (i.e., a substance that can repair the defects in semiconductor) and used it to improve the quantum efficiency of near infrared perovskite LEDs to over 21%.
"Based on this previous work, we further studied the light detection function of these devices and found that they also show remarkable photodetection performance," Chunxiong Bao, one of the researchers who carried out the study, told TechXplore. "In our recent study, we focused our efforts on simultaneously improving the light emitting and detection performance of perovskite-based diodes, demonstrating their feasibility as efficient light emitting and detection 'two-in-one' devices."
The perovskite material that Gao, Bao and their colleagues used to build their diode has several unique photoelectrical properties. In addition to a high photoluminescence quantum efficiency (PLQE), which is ideal for the development of high-performance LEDs, the material has a high absorption coefficient, enabling photodetection.
