|Bandara, J.; Willinger, K.; Thelakkat, M.: Multichromophore light harvesting in hybrid solar cells, Physical Chemistry Chemical Physics, 13, 12906-12911 (2011) -- DOI: 10.1039/C1CP21697J|
A new technologically relevant method for multichromophore sensitizing of hybrid blend solar cells is presented. Two dyes having complementary absorption in the UV-visible regions are individually adsorbed on nanocrystalline TiO2 powder. These dyed TiO2 nanoparticles are blended with an organic hole-conductor (HC) Spiro-OMeTAD in desired compositions and applied on a conducting substrate by doctor-blading at room temperature to fabricate multichromophore-sensitized hybrid blend solar cells. The external quantum efficiency (EQE) of the single hybrid layer system fabricated with two dyes, that absorb mainly UV (TPD dye) and visible regions (Ru-TPA-NCS dye), exhibited a clear panchromatic response with the sum of the EQE characteristics of each single dye cell. The first results of a multichromophore-sensitized solid-state solar cell showed Jsc of 2.1 mA cm−2, Voc of 645 mV, FF of 47% and efficiency of 0.65% at AM 1.5 G, 100 mW cm−2 illumination intensity. The Jsc of the multichromophore cell is the sum of the individually dyed solar cells. The process described here is technically very innovative and very simple in procedure. It has potentials to be adopted for panchromatic sensitization using more than two dyes in a single hybrid layer or layer-wise fabrication of a tandem structure at room temperature.