Cai Liu

Cd2SnO4 transparent conductive oxide: a promising alternative candidate for highly efficient hybrid halide perovskite solar cells

Organic–inorganic hybrid perovskite solar cells have attracted significant research attention in terms of perovskite materials, fabrication, device architecture, and interfacial engineering to increase their power conversion efficiency (PCE). However, the state-of-the-art front electrode of perovskite solar cells is mainly focused on indium tin oxide (ITO) and fluorine-doped tin oxide (FTO). To further improve the optical characteristics of front electrodes for perovskite devices, it is necessary to explore a new and suitable transparent conductive oxide material. Herein, we introduce a Cd2SnO4 film for constructing a perovskite device with a novel structure. The as-prepared Cd2SnO4 film shows higher optical transmission in the visible region compared to the FTO substrate. The matching energy band alignment can ensure efficient carrier transport and collection between the TiO2 layer and Cd2SnO4 electrode. The higher PCEs with an average of 15.58% under AM 1.5 irradiation for Cd2SnO4-based perovskite solar cells were obtained compared to those of the FTO-based devices. This renders the Cd2SnO4 film a promising transparent conductive oxide candidate for highly efficient perovskite solar cells. However, the toxicity of lead and cadmium components still remain a major concern for its commercial applications.

Highly reproducible perovskite solar cells with excellent CH3NH3PbI3−xClx film morphology fabricated via high precursor concentration

To meet the large-scale fabrication technology of perovskite solar cells in the future, a novel method is proposed herein to achieve an excellent and highly reproducible CH3NH3PbI3−xClx film based on a high concentration spinning process. Pinholes in the CH3NH3PbI3−xClx film were substantially reduced, leading to better uniformity and film coverage. The precursor ions and molecules promoted nucleation and growth while releasing by-products gradually, which was beneficial to continuous growth and crystallization of the perovskite film in high concentration conditions and then resulted in significantly enhanced optoelectronic characteristics and device performance. Up to 13.8% of power conversion efficiency had been achieved by employing the FTO/bl-TiO2/mp-TiO2/CH3NH3PbI3−xClx/Spiro-MeOTAD/Au device structure under AM1.5 global spectral irradiation (100 mW cm−2). This method offered an efficacious and simple strategy for a highly reproducible large-area fabrication process of low-cost perovskite solar cells.

Characterization of Zn 2 SnO 4 Thin Films Prepared by RF Magnetron Sputtering

Zn2SnO4 (ZTO) is a stable semiconductor in ZnO–SnO2 system and important transparent conducting oxide (TCO) predominantly used in optoelectronic devices. ZTO thin films were prepared by RF magnetron sputtering using Zn2SnO4 ceramic target in this paper. The effects of annealing temperatures and oxygen contents on characterization of ZTO thin films were studied. The results show that ZTO thin films prepared by RF magnetron sputtering are amorphous with an optical band gap of 3.22 eV. After annealing at 650°C in Ar atmosphere for 40 min, ZTO films possess a spinel structure with an optical band gap of 3.62 eV. The atomic force microscope (AFM) data of morphology reveals that the surface roughness of films is about 2 nm. The results of energy dispersive spectrometer (EDS) show that the concentration ratio of Zn to Sn is in the range from 1.44 to 1.57. The results of Hall-effect-measurement system reveal that the resistivity of films varies from 102 to 10–1 Ωcm, carrier concentration is about 1017 cm–3, and mobility ranges from 100 to 101 cm2 v–1 s–1.