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Despite the rapid development of polymer light-emitting diodes (PLEDs), the overall device efficiency is still limited because ∼80% of the generated light is trapped in a conventional device architecture by the high refractive index of organic materials and the optical confinement and internal reflection. The implementation of the energy dissipation compensation techniques is urgently required for further enhancement in the efficiency of PLEDs. Here, we demonstrate that incorporating the double-pattern Bragg gratings in the organic layers with soft nanoimprinting lithography can dramatically enhance the light extraction of trapped optical modes in PLEDs. The resulting efficiency is 1.35 times that of a conventional device with a flat architecture used as a comparison. The experimental and theoretical analyses indicate that the enhanced out-coupling efficiency is attributed to the combination of the ordinary Bragg scattering, the guided-mode resonance (GMR), surface plasmon polariton (SPP) modes, and the hybrid anticross coupling between GMR and SPP, leading to the extraordinary efficient photo flux that can transfer in direction of the leaky modes. We anticipate that our method provides a new pathway for precisely manipulating nanoscale optical fields and could enable the integration of different optical modes in PLEDs for the viable applications.

Efficient inverted polymer solar cell is reported upon by integrating with a small molecular 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL) at low processing temperature with thermal-evaporation and solution-process, resulting in the power conversion efficiencies of 3.70% and 3.47%, respectively. The potential of TPBi as an efficient EEL is associated with its suitable electronic energy level for electron extraction and hole blocking from the active layer to the indium tin oxide cathode.

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We constructed a concept of the full-organic carrier collection layer (CCL) used for polymer solar cells. The CCL is composed of dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile as hole collection layer (HCL) and chlorine-free solvents (formic acid (FA)) processed 4,7-Diphenyl-1,10-phenanthroline (Bphen) as electron collection layer, exhibiting good solubility, and environmental protection. The FA based device shows ideal power conversion efficiency (3.75%), which is higher than that of control device (3.6%). Besides, the HCL shows a different mechanism in hole extraction by functioning as a charge recombination zone for electrons injected from anode and holes extracted from the donor materials.