基于TiO2纳米管阵列的高效正面透光型染料敏化太阳能电池的制备及其光电性能

报道了一种基于TiO2纳米管(TNT)阵列正面透光型光阳极的高效染料敏化太阳能电池.将TNTs在450°C烧结后能避免其有序结构在HF处理过程中被破坏,使膜内高速电子传输通道被保留,有利于染料敏化太阳能电池(DSSC)实现高速电荷传输.再用HF、TiCl4、HF和TiCl4混合等溶剂对TNTs进行处理,提高其表面粗糙度以吸附更多染料.染料吸附量的增加能提高光阳极在300-570 nm波段光子捕获效率,该波段是染料吸收光子的主要区域.然而,在染料吸收光子较弱的长波段区域(570-800 nm)光子捕获效率的增加主要源于光阳极光散射率的提高.光阳极光子捕获效率的提高使DSSC的内外量子效率在全波段(300-800 nm)均有所增加,从而使短路电流明显提高.从电化学阻抗数据可知,与电子传输性能密切相关的电化学参数如电荷传输电阻、界面电荷复合电阻、电容、电子寿命、电子扩散长度和电子收集效率等在含处理过的TNTs光阳极DSSC中均有所改善,从而提高电池光电转换效率.含HF和TiCl4混合溶剂处理TNTs光阳极的DSSC最高光电转换效率能达到7.30%,比未处理的DSSC(5.38%)提高35.69%.

Fabrication and Photovoltaic Performance of High Efficiency Front-Illuminated Dye-Sensitized Solar Cell Based on Ordered TiO2 Nanotube Arrays

An efficient front-illuminated dye-sensitized solar cell (DSSC) based on ordered TiO₂ nanotube (TNT) arrays was prepared. Sintering at 450 ℃ avoided damage of the ordered TNTs during HF treatment. Fast electron transport channels were maintained in the membrane, for efficient charge transportat in the DSSC. The sintered TNT membranes were subsequently treated with HF, TiCl₄, and HF combined with TiCl₄. This formed a rougher surface, and allowed increased dye loadings. The increased dye loading improved the light harvesting efficiency of the photoanode at 300-570 nm wavelength range, which is the main absorption region of the adsorbed dye. The adsorbed dye had a low absorption at 570-800 nm wavelength range. The enhanced light harvesting efficiency of the photoanode originated from its increased diffuse reflectance. The incident-photon-to-current and absorbed-photon-to-current conversion efficiencies were increased over the entire 300-800 nm wavelength range. This resulted in an increased short-circuit current density of the DSSC. Electrochemical impedance spectroscopy indicated that electron transport and related parameters including charge transport resistance, interfacial charge recombination resistance, distributed chemical capacitance, electron lifetime, effective electron diffusion length, and collection efficiency were significantly improved in the DSSC containing the treated TNT photoanode. This also resulted in an enhanced photovoltaic performance. The maximum power conversion efficiency from combining HF and TiCl₄ treatments was 7.30%, which was a 35.69% enhancement compared with the nontreated DSSC (5.38%).