Manufacturing solar fabrics by electronic dyeing of textiles with 2D heterostructures

The rapid development of electronic devices and advanced sensors coupled with increasing concerns on global warming are driving requirements for portable, lightweight and flexible power sources to make our buildings smart and our portable devices independent from electricity grids. To this end, it is crucial to develop low-maintenance highly efficient energy sources that can provide local power, especially in ambient conditions. Thin-film photovoltaics offers such opportunity and are adaptable to any surface or device. Various ambient light photovoltaic technologies are investigated for harvesting energy from indoor light.

Solar panels are traditionally made of photovoltaic devices and mostly rigid materials such as glass are used as substrates. However, this is not ideal and practical for indoor use. Recently, solar fabrics are being pursued for building integrated and interior energy harvesting. Photovoltaic devices integrated into textiles can also be used as portable power sources when coupled with bags, cloths, etc. However, more research into material development and manufacturing is needed to bring such technology closer to applications. To endow textiles with photovoltaic capability, it is essential to integrate the electronic functionality while maintaining the soft, stretchable properties of the textile, and the look and feel the end-user expects. Integrating such sophisticated function into textiles, however, is vastly different from fabrication of photovoltaic devices on the flat surfaces of glass or even plastic flexible substrates due to the porous, 3D structure of woven fabrics.

This proposal addresses the manufacturing of new and emerging products related to the use of 2D materials for solar fabrics. The class of two-dimensional (2D) materials has expanded since since the isolation of graphene and now includes a great diversity of materials with various atomic structure and physical properties. Of particular interest for solar cells are the semiconducting transition metal di-chalcogenide (TMDC), with a band-gap ranging from visible to near infrared part of the spectrum (1.1 to 2.0 eV) and a significantly higher absorption coefficient per unit thickness (greater than Si, GaAs, and perovskites). These properties makes them extremely suitable for highly absorbing ultrathin photovoltaic devices for architectural and indoor applications and applications where lightweight or portability is highly desirable.

The proposed research will develop textile-compatible manufacturing of solar fabrics based on 2D materials including semiconducting TMDCs as active layers and highly conductive graphene as electrodes. One key achievement is to develop manufacturing processes that easily translate from prototyping to production to enable solar textiles to become real products rather than proofs-of-concept. To date, the use of high performance photoactive materials on textiles has provided power conversion efficiency approaching 10%. Photovoltaic devices based on 2D materials using 2D/2D heterojunctions as active layers have been demonstrated, exhibiting external quantum efficiencies exceeding 50% and absorbance exceeding 90%. Achieving such high power conversion efficiencies on textiles, above 50% is the second key achievement for the investigations pursued here.

This research will have impact and make a difference in the manufacturing area but also in other sectors such as healthcare, robotics and defence. The proposed research represents a technology leap towards autonomy and reliability of e-textile, reinforcing UK's position in e-textile markets. The proposed research has the potential to contribute various EPSRC prosperity outcomes such as "P1: Introduce the next generation of innovative and disruptive technologies", "P2: Ensure affordable solutions for national needs", "C2: Achieve transformational development and use of the Internet of Things" and "R1: Achieve energy security and efficiency".