Dye-sensitized solar cells (DSSCs) have been under intensive investigations since Prof. Grätzel contributed a respectable innovation for photovoltaic performance by introducing the mesoporous TiO
2 film as photoanode [
1-
11]. With the introduction of porous structure, dye molecules loading area and redox electrolyte contacting interface on TiO
2 film are increased in magnitude for several orders compared to plain ones [
1,
2]. The resulting enhancement in light absorption greatly improves cell efficiency and makes great strides for the practical application of DSSCs. Consequently, in order to further optimize DSSCs performance, great efforts have been devoted to TiO
2 film surface modification strategies [
12-
22]. Briefly, these modification methods can be summarized into two classes: 1) the blocking ones, which mainly aim at suppressing electron loss on film surface. The generally adopted approach is depositing an insulating oxide layer outside the nanoparticles by chemical or physical approach [
19-
22]; 2) the boosting ones, which include the methods trying to promote dye adsorption, electron injection, carrier transportation and collection [
12-
18]. Among these boosting methods, hydrochloric acid treatment of TiO
2 photoanode is a simple and effective approach [
15-
18], and the main effect is to enhance photocurrent. On the other hand, when boosting strategy concerning charge transportation is considered, the abundant surface electronic states are always mentioned [
2,
3,
8]. These surface states are customarily deemed to be trapping sites for photoinjected electrons in DSSCs, slowing down the charge transport and sometimes become recombination centers [
3,
8,
9,
13]. However, recent studies indicate that the influence of surface states seems to be more than just detention. With appropriate modulation approaches, former trapping states can also be helpful for electron conduction. Under ultraviolet (UV) illumination, Gregg et al. reported that a high concentration of photoactive surface states created in the mesoporous TiO
2 films could improve photoinjection and carrier transportation, and they improved the efficiency for 12.8% [
12]. Another paper published by Grätzel et al. also proved that electronic transport levels close to the conduction band arisen from visible light-soaking increased photovoltaic performance for 2.9% [
14]. These findings pioneer a new path to elevate DSSCs efficiency through adjusting electronic states in mesoporous TiO
2 by designing the film surface modification strategy. Unsatisfactorily, there is a common limitation for above irradiation methods—the widely used Li
+ ions in electrolyte will hinder the formation of the transport states [
13,
14]. Therefore, seeking an ideal method to create transporting states insensitive to certain ingredients in electrolyte is in urgent need now.