Dye-sensitized solar cells (DSSCs) are low-cost photovoltaic devices that provide a high energy conversion effi ciency of 11%. [ 1 ] High conversion effi ciency, good stability, and easy fabrication are essential for commercialization of DSSCs. [ 2 ] Although DSSCs with liquid electrolytes have been reported to exhibit high effi ciency, there has been interest in developing a solid-state DSSC (ssDSSC) due to its potential to decrease the overall weight of the cells and to provide long-term durability and fl exibility. Several methods have been developed to fabricate ssDSSCs employing quasi-solid or solid polymer electrolytes. [3][4][5][6][7][8][9][10][11] In ssDSSCs, hole transporting materials (HTMs) and the control of interfacial properties between the nanoporous TiO 2 layer and the HTM are critical to the photoconversion effi ciency of the cells. Recently, HTMs have been extensively investigated as potential replacements for conventional I 3 − /I − redox electrolyte systems using iodine (I 2 ) in DSSCs. [12][13][14][15][16][17][18] As an organic HTM, spiro-OMeTAD was used for an iodine free ssDSSC and showed higher effi ciency of 5.1%. [ 17 , 18 ] Inorganic HTMs such as CuI showed a good effi ciency of 4.7%, [ 12 ] but the crystal formation of metal oxide gradually reduced cell performance. [ 19 ] Another possibility is the utilization of p-type conducting polymers, e.g., polypyrrole, polyaniline, polydiacetylene, poly (3-octylthiopehene), and poly(3,4-ethylenedioxythiophene) (PEDOT). [20][21][22][23][24][25][26] These polymers are advantageous over other small molecules due to their low cost, good stability, simple fabrication using spin-coating, and easy preparation of designable structures. Recently, Ho et al. reported an iodine (I 2 )-free ssDSSC using polyaniline/carbon black composite with imidazolium iodide derivatives, which effectively generates I − / I 3 − redox couples without addition of iodine (I 2 ). [ 27 ] However, while conductive polymers offer many advantages, they show low energy conversion effi ciencies due to poor penetration into the nanopores of TiO 2 photoelectrodes that arises from mismatches between the molecular sizes of the polymers and the pore sizes of the TiO 2 layer. Recently, Yanagida et al. were successful at improving the power conversion effi ciency signifi cantly up to 2.85%, which was the highest effi ciency for an iodine-free ssDSSC using a conductive polymer as HTM. [28][29][30] The penetration of a conductive polymer into TiO 2 porous layers was successfully improved via the in situ photoelectrochemical polymerization of a heterocyclic monomer, e.g., 2,2'-bis(3,4-ethylenedioxythiophene) (bis-EDOT). [ 29 ] However, the maximum penetration depth of the conductive polymer into the TiO 2 layer was 4-5 μ m, above which cell effi ciency was decreased, resulting from insuffi cient interfacial properties of electrode/HTM despite increased dye adsorption. More recently, Liu et al. further improved cell efficiency up to 6.1% using indoline D149 dye as a sensitizer, [ 31 ] whe...

Nanopatterning provides facile process to well-arrayed mesoporous inorganic oxide films at low cost by using readily available pastes and elastomeric nanostamps. The fabricated nanopattern boosted the light-harvesting efficiency of dye-sensitized solar cells (DSSCs) by a light-trapping technique. The iodine-free solid-state DSSCs showed a 40 % increase in the current density and high efficiency (7.03 %).

We report a facile universal patterning method that provides well-arrayed patterns of polymer electrolyte membranes with a large electrochemical area using an elastomeric mold. The membrane electrode assembly fabricated with patterned Nafion membrane exhibited a high current density.

Polymer electrolyte membrane fuel cell is a promising zero-emission power generator for stationary/automotive applications. However, key issues, such as performance and costs, are still remained for an economical commercialization. Here, we fabricated a high-performance membrane electrode assembly (MEA) using an interfacial design based on well-arrayed micro-patterned membranes including circles, squares and hexagons with different sizes, which are produced by a facile elastomeric mold method. The best MEA performance is achieved using patterned Nafion membrane with a circle 2 μm in size, which exhibited a very high power density of 1906 mW/cm2 at 75 °C and Pt loading of 0.4 mg/cm2 with 73% improvement compared to the commercial membrane. The improved performance are attributed to the decreased MEA resistances and increased surface area for higher Pt utilization of over 80%. From these enhanced properties, it is possible to operate at lower Pt loading of 0.2 mg/cm2 with an outstanding performance of 1555 mW/cm2 and even at air/low humidity operations.

Solid-state dye-sensitized solar cell with 7.1% efficiency at 100 mW/cm(2) is reported, one of the highest observed for N719 dye. Excellent performance was achieved via a graft copolymer-templated, organized mesoporous TiO(2) film with a large surface area using spindle-shaped, preformed TiO(2) nanoparticles and solid polymer electrolyte.