Search

Perovskite-type photovoltaic devices with polysilane hole transport layers were fabricated by a spin-coating method. In the present work, poly(methyl phenylsilane) (PMPS) and decaphenylcyclopentasilane (DPPS) were used as the hole transport layers. First, structural and optical properties of the PMPS and DPPS films were investigated, and the as-prepared PMPS and DPPS films were amorphous. Optical absorption spectra of the amorphous PMPS and DPPS showed some marked features due to the nature of polysilanes. Then, microstructures, optical and photovoltaic properties of the perovskite-type photovoltaic devices with polysilane hole transport layers were investigated. Current density-voltage characteristics and incident photon to current conversion efficiency of the photovoltaic devices with the polysilane layers showed different photovoltaic performance each other, attributed to molecular structures of the polysilanes and Si content in the present hole transport layers.

In this paper, structural and photovoltaic properties of perovskite CH3NH3PbI3-xClx solar cells added with ammonium iodide (NH4I) are reported. The CH3NH3PbI3-xClx photovoltaic cells were fabricated by a hot air blow-assisted spin-coating method. By addition of NH4I, photovoltaic performance of the CH3NH3PbI3-xClx cell fabricated by the hot air blow-assisted spin-coating method was improved. The microstructure analysis of the resulting cells showed that the NH4I− added CH3NH3PbI3-xClx film was highly oriented along the (100) plane. Moreover, morphological changes of the NH4I− added CH3NH3PbI3-xClx film due to NH4I addition were also observed. The improvements of the photovoltaic performance, the crystal orientation, and the morphological changes of the CH3NH3PbI3-xClx are attributed to NH4I addition.

Surface and inside of silicon (Si) spheres prepared by a powder melting method were investigated. The lattice constant of the inside of Si spheres was larger than that of the surface of Si spheres, which was due to interstitial atoms trapped at gettering sites. To obtain the evidence for existence of the impurities, composition analysis was carried out. Florescence spectra of the surface and inside of Si spheres exhibited some information on impurities in both Si spheres.

Effects of AsI3 and NH4Cl addition to perovskite CH3NH3PbI3 precursor solutions on photovoltaic properties were investigated. TiO2/CH3NH3Pb(As)I3(Cl)-based photovoltaic devices were fabricated by a spin-coating technique, and the microstructures of the devices were investigated by X-ray diffraction and scanning electron microscopy. Current density-voltage characteristics and incident photon-to-current conversion efficiencies were improved by a small amount of As- and Cl-doping, which resulted in improvement of the efficiencies of the devices.

Perovskite-type CH3NH3(MA)PbI3−based photovoltaic devices were fabricated and characterized. Doping effects of cesium iodide (CsI), cesium bromide (CsBr) and tin bromide (SnBr2) on the photovoltaic properties and surface microstructures of the perovskite phase were investigated. Short-circuit current densities, open-circuit voltages and fill factors increased by CsI and SnBr2 addition. The surface coverage of the perovskite crystals was also improved by SnBr2 doping, which resulted in improvement of the fill factor. The cell prepared by a starting composition of MA0.95Cs0.05Pb0.95Sn0.05I2.90Br0.10 showed the best photovoltaic performance in the present work.

Microstructures, optical and photovoltaic properties of CH3NH3PbI3(1−x)Cl x perovskite films with copper(I) thiocyanate (CuSCN) additive were investigated. The CuSCN-added CH3NH3PbI3(1−x)Cl x films were prepared by a hot air blow-assisted spin-coating method. Current density–voltage characteristics of the photovoltaic device using the CuSCN-added CH3NH3PbI3(1−x)Cl x light-absorbing layer showed increases in short-circuit current density, open-circuit voltage, which resulted in increase in the conversion efficiency. Microstructure analysis showed that the crystal structure of the CuSCN-added CH3NH3PbI3(1−x)Cl x was a pseudocubic system. From these results, partial substitutions of Pb2+ and anions (I− and Cl−) by Cu ions (Cu+ and Cu2+) and SCN−, respectively, are considered to occur in the CuSCN-added CH3NH3PbI3(1−x)Cl x films. Based on the obtained results, reaction mechanisms of the CH3NH3PbI3(1−x)Cl x films with and without CuSCN additive were discussed.

Microstructures of spherical silicon solar cells with SnOx:Fy layers were investigated. Lattice constants of annealed SnOx:Fy layers were larger than those of as-prepared SnOx:Fy layers due to reduction of defects. From energy dispersive X-ray spectroscopy, it was confirmed that oxygen, fluorine and tin were diffused over silicon spheres, and composition ratios of the SnOx:Fy layers were changed by annealing. The mechanism of chemical reaction of SnO2 and SnO2/metal interface were also discussed.

Effects of polysilane-doped 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD) hole transport layers on photovoltaic properties were investigated by measuring current density–voltage characteristics and incident photon-to-current conversion efficiency of CH3NH3PbI3-based photovoltaic devices. Three kinds of polysilanes were used as the dopants. Due to the polysilane doping, conversion efficiencies of the CH3NH3PbI3 devices using the polysilane-doped hole transport layers were improved. Microstructures of the CH3NH3PbI3 devices were also investigated. Based on the results of the microstructure analysis, impact of silicon in the polysilanes doped into spiro-OMeTAD layer on photovoltaic properties were discussed.