Indoor power harvesting using hybrid perovskite materials

The world is increasingly using low-power, electronic devices in myriad ways, including as sensors for the Internet of Things (IoT), where billions of objects are connected to the internet to make a smart network, and in wearable electronic devices such as smart watches. Sensors are the fundamental components in the success of these ground-breaking technologies. By 2022, the total number of connected sensors and devices in IoT is expected to exceed 50 billion. How will all these devices be powered? Connecting every device to the electrical grid is too complex and expensive as it requires extensive installation and wiring, and furthermore increases electricity consumption. The use of batteries will limit the life span, bring service interruptions during battery replacement and will pose severe environmental issues at their disposal. My proposed research will bring a practical solution to this by developing inexpensive and environmentally friendly, new technologies to power these small electronic components.

My research vision is to power these wireless sensors and internet connected smart devices, using cost-effective and self-sustaining indoor energy harvesters. For this I will suitably 'tune' the properties of a family of electronic materials called 'hybrid perovskites' which combine favourable attributes of both organic and inorganic materials. The two physical properties that I envisage to exploit for this 'multiple' energy harvesting are (a) photovoltaic - converting light to electricity and (b) piezoelectricity - converting mechanical vibrations to electricity. In hybrid perovskites these two properties co-exist, opening new opportunities for multiple energy harvesting.

Inside buildings a vast reservoir of untapped energy is available in the form of lighting, mechanical vibrations and movement. Usually these are wasted energy inside the buildings. By combining the strengths of co-existing photovoltaic and piezoelectric activity in hybrid perovskites, I will develop different types of indoor energy harvesters, capable of harnessing energy from multiple sources of ambient energy. This multifunctional energy harvesting will lead to increased output electrical power and provide contingency in the scenario where one of the energy sources is not available or intermittent for e.g.; at night indoor lighting may be limited in supply but still vibrations inside the buildings can be pervasive (e.g.: air conditioning). Thus, by providing a continuous autonomous powering to sensors in IoT, my proposed project would enable these two technologies to achieve their potential to the fullest. This in turn will revolutionise our ways of life through more effective monitoring and communication, which will impact health care and the well-being of communities as well as the development of smart and energy efficient buildings and the digitization of manufacturing process.

The proposed research will not only strengthen UK's existing photovoltaic global prominence by adding a new dimension of 'indoor' light harvesting but will also spearhead the UK's piezoelectric energy harvesting research. The proposed project is extremely timely as the power efficiency of microprocessor technology and local electrical energy storage systems (e.g.: supercapacitors) are continuously improving. Hence a similar advance in indoor energy harvesting will lead to a convergence of technologies which will ultimately lead to successful implementation of energy harvesting systems and products.

Academic impact: The most immediate and direct beneficiaries of my project will be perovskite and organic solar cells research community especially those working on tandem architectures and the emerging indoor photovoltaics. The deeper understanding of mitigating carrier losses at the heterojunction interfaces, modification of the junction structure and new device structures to be developed can be usefully exploited in other optoelectronic devices such as lasers, LEDs and photodetectors. The new insights and understanding of a fascinating class of hybrid perovskite materials and the new applications demonstrated will generate considerable interest leading to new directions of academic research in fundamental science of multifunctional energy harvesting of photovoltaics and ferroelectricity/piezoelectricity but also in other energy harvesting such as pyroelectric, thermoelectric and RF harvesting. The interdisciplinary nature of my project, involving material scientists, physicists, chemists and electronic engineers will broaden the academic impact to several scientific fields. Doctoral students and young researchers will be receiving training on the fabrication of indoor photovoltaics and piezoelectric energy generators and on their fundamental understanding which will make them highly employable in various academic and industrial sectors.

Industrial impact: By 2025, the global industrial IoT market will grow to a $930 billion market and the wearable tech market will rise to $74 billion [Research forecast IDTechEX]. By providing a decarbonized, distributed and cost-efficient self-powering method, my project will enable the large-scale deployment of IoT in residential and office buildings. Even in industrial environments which are RF hostile, hence limits the application of wireless communication, my project can sustain IoT functionality through visible light communication. Research outcomes of this project will generate direct and immediate impact on the industrial collaborators: BAE Systems, Power Textiles Ltd, Veitch Cooper and KP technology, either by providing an extended market opportunity, new functionality in instrumentation and digitization of manufacturing. In addition to the above companies, others specialised in printed photovoltaics such as Oxford PV, Eight 19 and companies targeting to harvest environment energy such as Freevolt, WITT Energy and 8 power will also be potential beneficiaries of my project outputs.

Public Sector: In the short term, the distributed indoor energy harvesters that I develop will promote the establishment of 'net zero energy' and 'net positive energy' buildings and 'energy harvesting pavements'. In long term, my project outputs can be tailored to extend their applications in public sectors such as health care, transportation, community maintenance and national defence to enhance the infrastructure, and the quality of the service.

National impact- Health/wealth: Since residential and commercial buildings consume ~ 40 % of energy, by recycling part of the energy that is being used for lighting and harnessing the pervasive indoor energy- which is otherwise lost as waste- the security of our limited energy supply is improved. The cost-efficient, resilient indoor hybrid energy harvesting capabilities developing through my project can accelerate the realization of the UK's goals of increased energy efficiency, reduction in CO2 emissions and circular economy (tackling of energy trilemma) and thus contribute help UK to meet the target of reducing greenhouse gas emissions by 80% in 2050. By supporting to realise energy efficient buildings, my project is enabling the 'health and well-being of the occupants' by helping to advance ambient assisted living (AAL). By helping to achieve IoT to reach its full potential and developing energy efficient buildings, substantial economic growth and the well-being of society will be enhanced through my proposed research.