Co-produced: using [Co(en)(3)](2+/3+) based-electrolytes in p-type dye-sensitized solar cells (p-DSCs) gives record energy conversion efficiencies of 1.3 % and open-circuit voltages up to 709 mV under simulated sun light. The increase in photovoltage is due to the more negative redox potential of [Co(en)(3)](2+/3+) compared to established mediators.

Highly crystalline nanostructured nickel(II) oxide microballs (NiO-mBs) were developed for use in p-type dye-sensitized solar cells (p-DSC). Their high specific surface area and favorable optical properties yielded unprecedented photocurrent densities of 7.0 mA cm À2 under simulated sunlight (AM1.5; 1000 W m À2 ) and incident photon to charge carrier conversion efficiencies of 74% when applied in p-DSCs. This is an important step towards matching the performance of p-DSCs with their n-type counterparts for future tandem applications.Dye-sensitized solar cells (DSC) have attracted much attention as an alternative to conventional solar cells due to their projected low cost. 9,10 In conventional photoanodic DSCs (n-DSCs) the photocurrent results from dye-sensitized electron injection into n-type semiconductors such as TiO 2 . These photoanodes yield efficiencies of up to 12.3% and photocurrent densities (J SC ) of up to 17.66 mA cm À2 under simulated sunlight (1000 W m À2 , AM1.5). 11 In dye-sensitized photocathodes (p-DSC) electron transfer takes place from the valence band of the p-type semiconductor (NiO being the most commonly used to date) to the lowest energy SOMO (singularly occupied molecular orbit) of the dye, following photo excitation. 12,13 Photoanodes and photocathodes can be assembled together to produce tandem dye-sensitized solar cells (pn-DSCs) with a simple sandwich structure. According to Kirchhoff's circuit law, photovoltages are additives in this type of tandem architecture while the photocurrent is limited by the weakest performing photoelectrode, which is generally the photocathode. 12,14 The highest photocurrent density reported to date for p-DSCs (5.48 mA cm À2 ) under simulated sunlight (1000 W m À2 , AM1.5) is significantly lower than those typically reported for high efficiency n-DSCs. 5 This photocurrent mismatch represents one of the major obstacles towards the realization of high efficiency tandem pn-DSCs, calling for the development of photocathodes with improved current densities.Using a novel sensitizer (PMI-6T-TPA) (Fig. 1(a)) in conjunction with a mesoporous film comprised of commercially available NiO

A novel swivel-cruciform 3,3′-bithiophene based hole-transporting material (HTM) with a low lying highest occupied molecular orbital (HOMO) level for application in perovskite solar cells were synthesized.

This work demonstrates CuGaO2 as an efficient alternative to NiO as a photocathode material in dye-sensitized solar cells. A remarkable photocurrent has been achieved by the CuGaO2 photocathode.