Enhanced photovoltaic performance of polymer solar cells with photo-annealed titanium chelate

Photo-annealing treatment titanium chelate (TIPD) layer, which was the indium tin oxide (ITO) interface-modified layer, was used as a replacement for the thermal annealing treatment of TIPD. The power conversion efficiency (PCE) of photo-annealed TIPD-based polymer solar cells (PSCs) is quite low in the initial stage, but it dramatically increases following constant light illumination, and the cell achieves a saturated state after 9 min of light illumination. By employing the mixed films poly[1-(5-(4,8-bis(5-(2-ethylhocyl)-4-fluorothiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b']dithiophen-2-yl]thiophen-2-yl)-5,7-bis(2-ethylhexyl)-3-(5-methylthiophen-2-yl) 4H,8H-benzo[1,2,-c:4,5-c']dithiophene-4,8-dione] (PBDB-TF) and 2,2'-((2Z,2'Z)-(((4,4,9,9-tetrakis-(4-hexylphenyl)-4,9-dihydro-sindaceno [1,2-b:5,6-b']-dithiophene-2,7-diyebis(4-((2-ethylhexypoxy)thiophene-5,2- diyl))bis(methanylylidene)This(5,6-difluom-3-oxo-2,3-dihydro-1H-indene-2,1 -diylidene)) dimalononitrile (IEICO-4F) as photoactive layers, we improved the photovoltaic performance. The enhanced photovoltaic performance of TIPD films treated with photo-annealing was explained by the increased short-circuit current density (J(SC)). Efficient medium- and long-wavelength light transmittance and suppression of charge recombination are beneficial for enhancing the J(SC) value.