Engineering electrodes and metal halide perovskite materials for flexible/stretchable perovskite solar cells and light-emitting diodes

Organic-inorganic hybrid metal halide perovskites have excellent optoelectronic properties and are soft and resilient; therefore, they are appropriate for use in flexible and stretchable electronic devices. Commercialization of these perovskite optoelectronics requires development of flexible and stretchable electrodes that are compatible with perovskite optoelectronic properties. Compared to optoelectronic organic semiconductors, exploitation of the advantages of perovskite optoelectronics requires new perspectives in flexible and stretchable electrodes. Here we describe techniques to control the optical, electrical, and mechanical properties of metal halide perovskites that must be suitable for use in flexible and stretchable applications, and then discuss the most convincing candidates for flexible and stretchable electrode materials such as conducting polymers, low-dimensional carbon materials, and structured metals and their composites.