Highly Efficient Elastic Perovskite Solar Cells

Perovskite solar cells based on organic-inorganic metal halide perovskite absorbers have revolutionized solar research worldwide with the steepest ever increase in power conversion efficiency from 3.8% in 2009 to 22.1% as of March 2016. UK is already leading the world in PSCs research and development with the Oxford PV (a spin out company from Oxford University) aiming to bring the PSCs into market by 2017. Almost all of the studies reported on PSCs are based on only rigid (glass) or flexible (polymer or metal) substrates. For a wide range of promising applications ranging from integration on robotics, prosthetic to curved surfaces - it is important to have both flexibility and stretchability - i.e 'elastic' solar cells. Electronic materials and methods of manufacturing that produces flexible, stretchable, collapsible, and fracture-proof sources of power would revolutionize costumer electronics, bio-medical devices and robotics. Indoor light harvesting has recently attracted great attention because of unprecedented development of Internet of Things (IoT) which promises a future where a wide variety of consumer electronics, household amenities, bio-medical appliances as well as robotics could be integrated with and controlled via wireless communication systems and hence demand off-grid power sources. However, research focusing on indoor applications of PSCs is still in its infancy. In the light of these issues, the project proposed aims to develop highly efficient mechanically resilient elastic PSCs for indoor applications.

The proposed research will extend and complement the UK's existing strengths by adding additional dimension of 'stretchability' giving rise to a next generation of PSCs. The project proposed tackles the challenge of developing and manufacturing highly efficient elastic perovskite solar cells. The present project addresses this issue by developing materials and methods of manufacturing which, when combined, will produce elastic components for highly efficient elastic devices. The proposed research along with addressing these challenges, will have a wider impact on indoor photovoltaics by energy conservation at low light conditions and revolutionizing integration of perovskite photovoltaics to robotics. Elastic PSCs will revolutionize and widen the application base of solar cells integrated with moving parts and curvilinear surfaces with potential applications in intelligent prosthetic, prosthetic skin, smart textiles, consumer electronics, and biomedical devices. The techniques and materials developed during the project will not be limited to PSCs, but will have wider applicability to manufacturing of elastic solar cells and elastic electronics in general. The proposed project has the potential to emulate yet another revolution in the elastic electronics and photovoltaics industry and trigger transformation in various sectors including indoor photovoltics, robotics, stretchable and wearable electronics.

The UK is already a world-leader in perovskite solar cells (PSCs) with Oxford Photovoltaics (spin out company from Oxford University co-founded by Prof. Henry Snaith, collaborator in the proposed work) aiming to bring PSCs to market by 2017. However, current research worldwide is focused on PSCs fabricated on rigid or flexible substrates for outdoor applications which have major limitations in applications involving integration with moving and non-planar curved surfaces. Furthermore, many applications such as robotic arms are indoor based. These applications will benefit from solar cells that are sufficiently elastic (stretchability in addition to flexibility) and highly efficient to power them indoors. Indoor light harvesting has recently attracted great attention because of unprecedented development of Internet of Things (IoT) which promises a future where a wide variety of consumer electronics, household amenities, bio-medical appliances as well as robotics could be integrated with and controlled via wireless communication systems and hence demand off-grid power sources. With IoT in perspective, highly efficient, indoor-functional and mechanically resilient elastic PSCs (the proposed work) will revolutionise our way of life.
The work proposed will, in particular, transform three areas: PSCs, Stretchable/Wearable Electronics and Robotics.
1. PSCs: Technology benchmarking and market analysis reveal that by 2025 the PSCs market is expected to reach $214 million.
2. Stretchable/Wearable electronics: Over $1 billion has been spent on research on stretchable electronics in 35 years. A notable example of this was the 2012 round of $12.5 million by MC10 in the USA, a company exclusively dedicated to commercialising stretchable electronics. It is expected that wearable electronics business currently at $20 billion (in 2015/16) will grow to $70 billion by 2025, the dominant sector will remain the healthcare sector which merges medical, fitness and wellness.
3. Robotics: Existing and emerging robotics market sectors amount to a $25bn market today and will grow to $123bn by 2026.
The above estimates are provided by IDTechEx (http://www.idtechex.com).
The team I lead in this proposal is unique - we are renowned experts in our respective fields, which are complementary and necessary for the success of this proposal. We have a strong track-record in PSCs, molecular materials (novel hole transport materials and interface modifiers), graphene and CNTs, stretchable devices and microelectronic fabrication and have worked together before in these individual areas - but for the first time are bringing together our skills for this new concept on highly efficient elastic perovskite solar cells. The research proposed concerns novel but fundamental research with great potential for commercial application, as evidenced by the direct participation of industrial partners, Shadow Robot Company UK, G24Power, and NSG Pilkington as well as involvement of Dupont Teijin Films.
The project will provide additional skills resource to allow for training of doctoral candidates in the photovoltaics/ elastic electronics/ device fabrication sectors, plus given the integration focus of the research, this will also provide for technologists geared towards enabling Internet of Things. This includes training in advanced characterisation, advanced mechanical-testing for elastic PSCs, fabrication techniques and integration to robotics and wearable electronics that can be used in a variety of projects/applications. In addition, the immediate interaction with our industrial partners will add direct value to myself and training to the PDRA. This will offer us increased insight into the industrial needs, constraints and avenues for application of state-of-the-art research. The proposed work will enable me to establish nodal centre of excellence in stretchable smart devices at the University of Edinburgh thereby enhancing my credentials as a leader in this area.