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.

Automated summary

The study demonstrates that using photo-annealing treatment on TIPD layer can significantly enhance the power conversion efficiency of polymer solar cells, and the enhancement is attributed to improved optical properties and suppression of charge recombination for increased short-circuit current density.