Lights, Camera, Energy!

The proliferation of Internet of Things (IoT) devices has brought about many changes in recent years. These devices, interconnected through the internet, have found applications in various industries, ranging from smart homes and healthcare to industrial automation and agriculture. The growth in the adoption of IoT devices can be attributed to their ability to collect and exchange data seamlessly, enabling improved efficiency, automation, and decision-making processes.

However, this surge in IoT adoption comes with a set of challenges, particularly concerning the energy consumption of these devices. Many IoT devices are powered by batteries, and while advancements in battery technology have improved their lifespan and energy efficiency, the sheer volume of devices in operation raises concerns about their collective environmental impact. The manufacturing, transportation, and disposal of batteries contribute to carbon emissions and pose challenges in terms of waste management. Additionally, the extraction of materials for battery production can have adverse effects on ecosystems.

Furthermore, the continuous need for power sources and frequent battery replacements contribute to increased costs and maintenance efforts for individuals and businesses deploying these devices at scale.

Towards a better, more sustainable path forward, researchers have been exploring organic-based optoelectronic technologies. These devices can replace the functions of many traditional electronics, but consume less energy in the process. Organic photovoltaic cells (OPVs) and organic photodetectors (OPDs), in particular, have received a lot of attention because they can efficiently generate electricity from light and act as image sensors, respectively.

These are important capabilities for many IoT devices, but manufacturing of distinct OPVs and OPDs has proven to be costly, greatly limiting the applications in which they can be utilized. A team led by researchers at the Korea Institute of Science and Technology have devised a possible solution to this problem, however. They have developed a single device that has the properties of both OPVs and OPDs. This gives it the ability to both generate electricity and act as an image sensor, but without the complexity and cost of other existing technologies.

The multifunctional device also outperforms competing technologies. The photoelectric conversion efficiency of the OPV function exceeds 32%, which is quite exceptional. The image sensing capability of the OPD function exhibits a linear dynamic range surpassing 130 dB — a 30% boost over similar organic-based optoelectronic devices. This makes the image sensor very adept at capturing scenes under conditions of very low light levels.

Taken together, these functions essentially combine to produce a self-powered camera. However, this is a very early prototype. The image sensor only consists of a single pixel. While this could, in theory, be extended to a higher resolution array in the future, as it presently stands it is closer to an ambient light level sensor than a true camera.

Despite this limitation, the technology does have applications today. A researcher contributing to this work noted of the device that "while primarily functioning as an energy harvester, it can also be applied to detect movement and recognize motion patterns in environments without light. This holds great promise not only for human-computer interaction research but also in various industrial sectors, including smart indoor environments."