Ormoclear/Ag/WO3 (OAW) films with ultrahigh transparency are designed for application in organic solar cells (OSCs). When the thicknesses of Ag and WO3 are fixed at 8 nm and 30 nm, respectively, excellent transparency that is independent of Ormoclear thickness is successfully achieved by employing soft materials instead of inorganic dielectrics. Oxygen plasma treatment prior to the deposition of Ag introduces the polar functional groups on the Ormoclear surface, which results in increasing the surface hydrophilicity, thereby enhancing the wettability of Ag. From the surface modification, OAW exhibits low sheet resistance (4.8 ohm sq‐1), high transmittance of up to 96.3% at 535 nm, and enhanced efficiency of 7.63% of OSCs. Moreover, nanoimprint lithography is used to prepare a well‐ordered nanopatterned OAW with dimple diameter of 90 nm, leading to further increase in photocurrent density by 17%, compared to that with a planar indium tin oxide (ITO) electrode.

A novel method to synthesize a hydrogenated molybdenum oxide (H y MoO 3Àx ) thin film by irradiation of photons using a KrF laser (l ¼ 248 nm) on an ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 $4H 2 O) precursor layer is demonstrated. The laser-assisted synthesis is simple, and can be conducted in an ambient atmosphere without damaging the underlying bottom electrode and plastic substrate. The exposure time (30 ns) is extremely short compared to thermal annealing (>3 min). Because the highenergy photons are absorbed by the MoO 3 layer and provide the activation energy for the reaction, the hydrogen atoms that dissociate from the ammonium molecules bond to the MoO 3 ; this process yields a H y MoO 3Àx thin-film. By controlling the laser energy, the stoichiometry of the H y MoO 3Àx layer can be manipulated to simultaneously obtain advantageous electrical properties of both high work function (5.6 eV) and electrical conductivity (9.9 mS cm À1). The H y MoO 3Àx hole transport layer (HTL) is successfully demonstrated on flexible top-illuminated PTB7:PCBM organic solar cells (OSCs). This OSC has good mechanical flexibility, and 75% higher short-circuit current than the device with a PEDOT:PSS HTL.Finite-domain time-difference simulations were conducted to verify the enhancement of the photocurrent. The thin layer of H y MoO 3Àx was proven to be suitable for the microcavity condition which allows a resonant wavelength match to the PTB7:PCBM active layer.

Top-illuminated flexible organic solar cells with a high power conversion efficiency (≈6.75%) are fabricated using a dielectric/metal/polymer (DMP) electrode. Employing a polymer layer (n = 1.49) makes it possible to show the high transmittance, which is insensitive to film thickness, and the excellent haze induced by well-ordered nanopatterns on the DMP electrode, leading to a 28% of enhancement in efficiency compared to bottom cells.

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Wavelength-scale inverted pyramid structures with low reflectance and excellent haze have been designed for application to polymer solar cells (PSCs). The wavelength-scale structured haze films are fabricated on the back surface of glass without damages to organic active layer by using a soft lithographic technique with etched GaN molds. With a rigorous coupled-wave analysis of optical modeling, we find the shift of resonance peaks with the increase of pattern's diameter. Wavelength-scale structures could provide the number of resonances at the long wavelength spectrum (λ = 650-800 nm), yielding enhancement of power conversion efficiency (PCE) in the PSCs. Compared with a flat device (PCE = 7.12%, Jsc = 15.6 mA/cm(2)), improved PCE of 8.41% is achieved in a haze film, which is mainly due to the increased short circuit current density (Jsc) of 17.5 mA/cm(2). Hence, it opens up exciting opportunities for a variety of PSCs with wavelength-scale structures to further improve performance, simplify complicated process, and reduce costs.