Heteroleptic ruthenium complexes containing uncommon 5,5′-disubstituted-2,2′-bipyridine chromophores for dye-sensitized solar cells
作者:Feng-Rong Dai、Wen-Jun Wu、Qi-Wei Wang、He Tian、Wai-Yeung Wong
DOI:10.1039/c0dt01043j
日期:——
Four new heteroleptic ruthenium sensitizers [Ru(4,4â²-carboxylic acid-2,2â²-bipyridine)(L)(NCS)2] (L = 5,5â²-bis(4-octylthiophen-2-yl)-2,2â²-bipyridine (1), 5,5â²-bis(N,N-diphenyl-4-aminophenyl)-2,2â²-bipyridine (2), 5,5â²-bis(5-(N,N-diphenyl-4-aminophenyl)-thiophen-2-yl)-2,2â²-bipyridine (3) and 5,5â²-bis(4-octyl-5-(N,N-diphenyl-4-aminophenyl)-thiophen-2-yl)-2,2â²-bipyridine (4)) were synthesized, characterized by physicochemical and computational methods, and utilized as photosensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The λmax of the metal-to-ligand charge transfer (MLCT) absorption of these four ruthenium dyes (527 nm for 1, 535 nm for 2, 585 nm for 3 and 553 nm for 4) can be tuned by various structural modifications of the ancillary ligand and it was shown that increasing the conjugation length of such ligand reduces the energy as well as the molar absorption coefficient of the MLCT band. The maximum incident photon to current conversion efficiency (IPCE) of 41.4% at 550 nm, 38.6% at 480 nm, 39.4% at 470 nm and 31.1% at 480 nm for 1-, 2-, 3- and 4-sensitized solar cells were obtained. Respectable power conversion efficiencies of 3.00%, 2.51%, 2.00% and 2.03% were realized, respectively, when the sensitizers 1, 2, 3 and 4 were used in DSSCs under the standard air mass (AM) 1.5 sunlight illumination (versus 5.9% for standard N719).
合成了四种新的多齿配位的钌敏化剂[Ru(4,4'-羧酸-2,2'-联吡啶)(L)(NCS)2](L=5,5'-双(4-辛基噻吩-2-基)-2,2'-联吡啶(1)、5,5'-双(N,N-二苯基-4-氨基苯基)-2,2'-联吡啶(2)、5,5'-双(5-(N,N-二苯基-4-氨基苯基)-噻吩-2-基)-2,2'-联吡啶(3)和5,5'-双(4-辛基-5-(N,N-二苯基-4-氨基苯基)-噻吩-2-基)-2,2'-联吡啶(4)),并通过物理化学和计算方法对其进行了表征,将其作为纳米晶染料敏化太阳能电池(DSSCs)的光敏剂。通过对辅助配体的结构修饰,调节了这四种钌染料金属到配体电荷转移(MLCT)吸收的最大波长(分别为527 nm、535 nm、585 nm和553 nm),结果表明,增加这种配体的共轭长度会降低MLCT带的能量和摩尔吸收系数。获得了1-、2-、3-和4-敏化太阳能电池的最大入射光子电流转换效率(IPCE),分别为550 nm处41.4%、480 nm处38.6%、470 nm处39.4%和480 nm处31.1%。在使用敏化剂1、2、3和4的DSSCs中,分别实现了3.00%、2.51%、2.00%和2.03%的可观功率转换效率,在标准大气质量(AM)1.5阳光照射下(标准N719为5.9%)。