We report a simple method for preparing transparent conductive graphene films using a chemically converted graphene (CCG) suspension that was obtained via controlled chemical reduction of exfoliated graphene oxide (GO) in the absence of dispersants. Upon thermal annealing of the CCG films, the films displayed a sheet resistance on the order of 103 Ω·◻−1 at 80% transparency (550 nm), with a bulk conductivity on the order of 102 S·cm−1. FT-IR, UV−visible, and X-ray photoelectron spectroscopy results showed that the combination of the controlled reduction of GO in suspension and thermal annealing of the CCG films efficiently restored the sp2 carbon networks of the graphene sheets, facilitating charge carrier transport in the individual CCG sheets. Furthermore, grazing-incidence X-ray diffraction results showed that the thermal annealing of the CCG films reduced the interlayer distance between the CCG sheets to a distance comparable to that in bulk graphite, facilitating charge carrier transport across the CCG sheets. Polymer solar cell devices composed of the CCG films as transparent electrodes showed power conversion efficiencies, η, of 1.01 ± 0.05%, which corresponded to half the value (2.04 ± 0.1%) of the reference devices, in which indium tin oxide-covered glass was used for the transparent electrode.

The power‐conversion efficiency of an organic photovoltaic cell composed of poly(3‐hexylthiophene) and (6,6)‐phenyl‐C61‐butyric acid methyl ester is enhanced significantly by controlling the surface morphology of the photoactive layer. The hierarchical micro‐/nanostructures of the active‐layer surface are fabricated by nanoimprinting the active layer with a commercially available, anodic aluminum oxide (AAO) membrane filter (see image).

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Top-illuminated flexible polymer solar cells with 3D micoresonant cavity provide not only powerful light-trapping but also electrical enhancement, resulting in significant enhancement of power efficiency (26.4%). Capping layer (CL) enhanced the transmittance of the transparent electrodes, increasing electric field intensity in the photoactive layer by forming microresonant cavity, and the nano-pattern on the rear electrodes caused significant enhancement to the Jsc by improving light absorption and charge collection.

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