Flexible multijunction solar cells embedded inside smart dust modules for outdoor applications to Smart Grids

The functioning of self-sustaining smart dust modules plays a vital role in the development of the smart electric grid. In this work, we first devise a flexible triple-junction III-V solar cell embedded inside a smart dust module suitable for outdoor applications. These flexible solar cells are demonstrated to have a bending radius of over 5 cm and exhibit a conversion efficiency of around 25% under air mass 1.5G (1 sun) conditions. Under normal incidence of sunlight at the same conditions, our cell with its small active area of 0.4 cm(2) can generate around 10.1 mW of electrical power. This is sufficient to meet the direct current power consumption (similar to 5.4 mW) requirements of our dust module, which includes a temperature/moisture sensor, a 3-axis linear accelerometer, and a Bluetooth chip. In comparison to a silicon-based flexible solar cell, our demonstrated III-V solar cell is smaller, requiring approximately 40% of the area to produce the same electrical power output. Our dust module is controlled using a self-developed Android application installed on a smartphone and can sustain continuous wave operation for data collection and wireless transmission even when the incident angle of the sunlight reaches 75 degrees. Pulse-mode operation is still possible even in the case of nearly 90 degrees illuminations (for example, at sunset). Overall, the measurement results for this flexible solar cell are promising, allowing for further reduction in the size of a self-sustaining smart dust module with improved reliability. These advantages could facilitate development of the next generation of energy saving smart electric grids.

Automated summary

The research focuses on a flexible solar cell embedded in a self-sustaining smart dust module, showing high conversion efficiency and compact design, meeting the power requirements of the module, controllable through a smartphone application, with good adaptability to sunlight, providing important support for the development of energy-saving smart electric grids.