Mechanically robust, stretchable organic solar cells via buckle-on-elastomer strategy

In recent years, the exploitation of stretchable organic solar cell (OSC) has attracted significant research interests due to the rapid progress of wearable electronics. However, the development of a stretchable OSC is quite challenging since it has a strict requirement for the mechanical deformability and durability of each constituent layer in device. In this work, we successfully fabricated an efficient, stretchable inverted OSC by adopting a buckle-on-elastomer strategy, for which an ultrathin poly(ethylene naphthalate) (PEN) substrate coupled with a pre-strained (100%) 3M elastomeric tape was employed as the device substrate. Owing to the pre-strained status of the elastomer, the ensemble wrinkle will be formed in response to accommodate the strain once the pre-strain was released, which can afford the derived OSC with a much improved mechanically robustness and stretchability. As a result, we demonstrated that a pristine efficient (PCE: 5.61%) OSC using such buckling scaffold can remain its 74% efficiency under 30% compression and, more importantly, can still retain its 64.3% efficiency after 50-cycle compression-stretching testing from 0% to 30% compression. Besides, the effects of mechanical deformation and durability on the electrical performance are also investigated. This work proves that the buckleon- elastomer strategy can be a good solution for realizing efficient OSCs with reasonably good mechanical durability, revealing great potential serving as an ultrathin and lightweight power source for wearable device applications.