CdS/CdSe Co-sensitized Solar Cells Based on Hierarchically Structured SnO2/TiO2 Hybrid Films.

Zeng Chen,Wenping Kong,Wei Li,Zhenlong Zhang,Weifeng Zhang,Chunli Diao,Chaochao Wei,Shengjun Li

doi:10.1186/s11671-016-1493-7

Abstract

SnO2 nanosheet-structured films were prepared on a fluorine-doped tin oxide (FTO) substrate using ZnO nanosheet as template. The as-prepared SnO2 nanosheets contained plenty of nano-voids and were generally vertical to the substrate. TiO2 nanoparticles were homogeneously deposited into the intervals between the SnO2 nanosheets to prepare a hierarchically structured SnO2/TiO2 hybrid film. The hybrid films were co-sensitized with CdS and CdSe quantum dots. The sensitized solar cells assembled with the SnO2/TiO2 hybrid film showed much higher photoelectricity conversion efficiency than the cells assembled with pure TiO2 films. The lifetime of photoinduced electron was also investigated through electrochemical impedance spectroscopy, which showed that the SnO2/TiO2 hybrid film electrode is as long as the TiO2 film electrode.

Highlights

In recent years, quantum dot (QD)-sensitized solar cells have attracted remarkable attention because of the multiple exciton generation characters
ZnO nanosheet-structured film was firstly electrodeposited on fluorine-doped tin oxide (FTO) substrate
If the immersion time was long enough, all the ZnO nanosheets on the FTO substrate might be totally dissolved into the solution

Summary

Introduction

Quantum dot (QD)-sensitized solar cells have attracted remarkable attention because of the multiple exciton generation characters. Compared with TiO2, SnO2 has many advantages. The energy gap of SnO2 is about 3.6 eV which may reduce the effect of UV light in the sunlight on the solar cell performance and improve their long-term stability [6]. The electron mobility of SnO2 is about 150 cm V−1 s−1 which is much higher than that of TiO2 (1 cm V−1 s−1) [7, 8]. SnO2 films which are suitable for sensitized solar cells could be obtained without high temperature calcination [9, 10]. Some teams began to apply nanoporous SnO2 as Specific nanostructure of nanoparticles, such as nanorod, nanosheet, and nanowire, could bring some distinctive properties. Some teams had attempted to prepare SnO2 nanosheets. Fei L et al prepared SnO2 nanosheets using graphite sheets as template [16].

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Results

Conclusion