Innovative textile-based washable polymer solar cells are realized by suppressing the hydrolysis of the encapsulation barrier with a SiO2–polymer composite.

A practically applicable type of wearable polymer solar cells (PSCs) is presented with the enhanced performance by exploiting simply embodied, plasmonic nanostructures on a commercially available textile platform of optically opaque, geometrically uneven, and physically permeable woven fabrics that are commonly not compatible with organic photovoltaics. On a conformable fabric substrate preferentially processed with organic/inorganic multilayers for both planarization and encapsulation, the fabrication of top-illuminated, inverted type of PSCs with a transparent top electrode consisting of optimized dielectric/metal/dielectric multilayers is conducted, where a nanostructure of disorderly distributed elliptical hemispheres is implanted at an opaque bottom silver electrode by spin-coated silica nanoparticles in advance of depositing this electrode. The nanostructured bottom electrode promotes the light trapping effect at wavelengths of the surface plasmon resonance, as well as reduces the electrical Ohmic loss, thereby achieving a device with the power conversion efficiency of ∼8.71% at the given plasmonic device, where a net improvement of the efficiency is ∼1.46% compared to the planar device comprising otherwise same constituent layers. Systematic studies on optical properties and associated photovoltaic performance in experiments, together with analytic numerical modeling, allow quantitative understanding of the underlying physics, providing optimal rules for tailoring random nanostructures to the textile PSCs in the context of high-performance wearable photovoltaics.

A simple route to enhance the efficiency of polymer solar cells is presented by exploiting plasmonically assisted photon recycling. Embedded gold nanorods promote the photon radiation from excitons, and hence improve the effective diffusion length of excitons.

Spectral upconversion systems placed underneath solar cells have the considerable potential for enhancement of the photovoltaic performance as they allow additional absorption for the solar photons with energy below the bandgap of active materials. However, their application to a type of ultrathin solar cells for achieving the meaningful benefit of the efficiency improvement is challenging, because a pre‐existing rear‐side reflector that substantially increases the photon absorption needs to be eliminated for photonic interaction between photovoltaic active layer and upconversion medium, and hence a level of cell efficiency becomes limited. Herein a facile strategy is presented that can circumvent the issue of performance deterioration arising from the expelled reflector for integrating plasmonically enhanced upconversion systems with ultrathin nonfullerene‐based polymer solar cells. By employing a wavelength‐selectively reflective rear electrode of metal/dielectric multilayer that enables the photon penetration only at excitation and emission wavelengths of the upconversion process, the effect of photocurrent improvement with uncompromising efficiency levels can be expected from the plasmonic upconversion backplane comprising NaYF4:Yb3+,Er3+ core‐shell nanoparticles and metallic nanostructure. Systematic studies of optical process and resulting device performance in both experiments and numerical modeling provide the optimal design scheme for high‐performance polymer solar cells assisted with upconversion systems.