Polymer solar cells have drawn a great deal of attention due to the attractiveness of their use in renewable energy sources that are potentially lightweight and low in cost. Recently, numerous significant research efforts have resulted in polymer solar cells with power conversion efficiencies in excess of 9% (ref. 1). Nevertheless, further improvements in performance are sought for commercial applications. Here, we report polymer solar cells with a power conversion efficiency of 10.02% that employ a non-conjugated small-molecule electrolyte as an interlayer. The material offers good contact for photogenerated charge carrier collection and allows optimum photon harvesting in the device. Furthermore, the enhanced performance is attributed to improved electron mobility, enhanced active-layer absorption and properly active-layer microstructures with optimal horizontal phase separation and vertical phase gradation. Our discovery opens a new avenue for single-junction devices by fully exploiting the potential of various material systems with efficiency over 10%.In recent decades, polymer solar cells (PSCs) based on conjugated polymers as donors (D) blended with fullerene derivatives as acceptors (A) have received an enormous amount of attention in renewable energy sources because of the promise of low cost, flexibility and large-area fabrication 2-5 . To date, the best reported power conversion efficiency (PCE) in PSCs is ∼9-10%, but most values remain below 10%, especially in single-junction PSCs 6-11 . It is therefore highly desirable to develop novel materials and devices for the creation of single-junction PSCs with excellent efficiencies.To achieve such high efficiencies, energy loss in PSCs should be minimized. In general, energy loss originates directly from the reflection, transmission, exciton recombination and exciton annihilation of active and/or interface layers, as well as the accumulation on electrodes. The key is therefore to develop suitable materials for active and interfacial layers that can significantly reduce the loss of energy. For active-layer materials, considerable progress has been demonstrated with broadband absorption and high carrier mobility, resulting in state-of-the-art single-junction PSCs with PCEs up to ∼10% 12,13 . Meanwhile, triple-junction tandem devices have also been developed that achieve a high PCE of 11.5%, by combining different high-performance active-layer materials [14][15][16] . Before the studies on active-layer materials and devices, the interlayer between the cathode and active layer was also thought to be an important factor in the realization of highly efficient PSCs by avoiding the accumulation of excitons. The selection of proper electrodes with matched workfunctions is an effective method to reduce this accumulation and improve efficiency. However, the availability of suitable electrodes is limited for the emerging active-layer materials of different energy levels, so some investigators have suggested using an interfacial layer between the active layer and electro...

Transparent, UV-filtered, anti-freezing, and moisture-retention organohydrogel-based sensors are prepared by incorporating ions/microparticles into a binary solvent system.

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Two blue fluorophores with excellent hybridized local and charge-transfer (HLCT) and "hot exciton" properties were developed as the blue emitter and the host for orange-red phosphor to achieve highly efficient fluorescent/phosphorescent (F/P) hybrid white organic light-emitting diodes (WOLEDs) in a single-emissive-layer single-dopant (SEML-SD) architecture even at a high concentration of phosphorescent dopant. In the devices, part of the triplet excitons of the blue fluorophores can be utilized to realize reverse intersystem crossing from the triplet excited states to the singlet excited states for blue emission, and the diffusion volume range of the triplet excitons is reduced significantly. When the phosphorescent dopant concentration is up to 1.0 wt %, which is ten times higher than the traditional single-EML-SD F/P hybrid WOLEDs, highly efficient white emission was still achieved with maximum total external quantum efficiency (EQE) of 23.8%, current efficiency (CE) of 56.1 cd A(-1), and power efficiency (PE) of 62.9 lm W(1-). The results will supply a novel method for obtaining high efficiency F/P hybrid WOLEDs in a SEML-SD architecture with easily controllable doping concentration.