Incorporating Zn 2 SnO 4 Quantum Dots and Aggregates for Enhanced Performance in Dye‐Sensitized ZnO Solar Cells

The performance of dye‐sensitized ZnO solar cells was improved by a facile surface‐treatment approach through chemical‐bath deposition. After the surface treatment, the quantum dots of Zn 2 SnO 4 were deposited onto ZnO nanoparticles accompanied by the aggregations of Zn 2 SnO 4 nanoparticles. The ZnO film displayed a better resistance to acidic dye solution on account of the deposited Zn 2 SnO 4 nanoparticles. Meanwhile, the open‐circuit photovoltage was greatly enhanced, which can be ascribed to the increased conduction‐band edge of ZnO and inhibited interfacial charge recombination. Although the deposition of Zn 2 SnO 4 decreased the adsorption amounts of N719 dye, the aggregates of Zn 2 SnO 4 with a size of 350–450 nm acted as the effective light‐scattering layer, thereby resulting in an improved short‐circuit photocurrent. By co‐sensitizing 10 μm‐thick ZnO film with N719 and D131 dyes, a top efficiency of 4.38 % was achieved under the illumination of one sun (AM 1.5, 100 mW cm −2 ).