Omnidirectional light absorption enhancement of perovskite solar cells by an antireflection film with holographic lithography microstructures.

We report an omnidirectional light absorption enhancement of a perovskite solar cell (PSC) using antireflection (AR) film with soft imprinted microstructures from master molds via holographic lithography technology, which has high throughput and repeatability. The PSC's omnidirectional power conversion efficiency (PCE) enhancement is achieved by reducing Fresnel surface reflections and enhancing the optical path length. The maximum PCE of PSCs with AR film is up to 20.27%, corresponding to an absolute increase of 0.93% compared to 19.34% of control devices. Significantly, the enhancements of PCE increase with incident angle enlargement, which attributes to more effective Fresnel surface reflection suppression. Moreover, AR films exhibit water and dust repellent properties due to hydrophobicity, which is beneficial for PSC's long-term stability and light harvesting.

Mechanically robust stretchable organic optoelectronic devices built using a simple and universal stencil-pattern transferring technology.

Stretchable electronic and optoelectronic devices based on controllable ordered buckling structures exhibit superior mechanical stability by retaining their buckling profile without distortion in repeated stretch-release cycles. However, a simple and universal technology to introduce ordered buckling structures into stretchable devices remains a real challenge. Here, a simple and general stencil-pattern transferring technology was applied to stretchable organic light-emitting devices (SOLEDs) and polymer solar cells (SPSCs) to realize an ordered buckling profile. To the best of our knowledge, both the SOLEDs and SPSCs with periodic buckles exhibited the highest mechanical robustness by operating with small performance variations after 20,000 and 12,000 stretch-release cycles between 0% and 20% tensile strain, respectively. Notably, in this work, periodic-buckled structures were introduced into SPSCs for the first time, with the number of stretch-release cycles for the SPSCs improved by two orders of magnitude compared to that for previously reported random-buckled stretchable organic solar cells. The simple method used in this work provides a universal solution for low-cost and high-performance stretchable electronic and optoelectronic devices and promotes the commercial development of stretchable devices in wearable electronics.

Two-Dimensional Stretchable Organic Light-Emitting Devices with High Efficiency.

Stretchable organic light-emitting devices (SOLEDs) with two-dimensional (2D) stretchability are superior to one-dimensional (1D) SOLEDs in most practical applications such as wearable electronics and electronic skins and therefore attract a great deal of interest. However, the luminous efficiency of the 2D SOLEDs is still not practical for the purposes of commercial applications. This is due to the limitations on materials and structures from the physical and electrical damage caused by the complicated interactions of the anisotropic stress in 2D stretchable system. Here 2D SOLEDs with excellent stretchability and electroluminescence performance have been demonstrated based on an ultrathin and ultraflexible OLED and a buckling process. The devices endure tensile strain of 50% in area with a maximum efficiency of 79 cd A-1, which is the largest luminescent efficiency of 2D SOLEDs reported to date. The 2D SOLEDs survive continuous cyclic stretching and exhibit slight performance variations at different strain values. The 2D SOLEDs reported here have exhibited enormous potential for various practical applications.