Kazufumi Kohno

Low temperature fabrication of perovskite solar cells with TiO2 nanoparticle layers

TiO2/CH3NH3PbI3-based photovoltaic devices were fabricated by a spin-coating method using a mixture solution. TiO2 require high-temperature processing to achieve suitably high carrier mobility. TiO2 electron transport layers and TiO2 scaffold layers for the perovskite were fabricated from TiO2 nanoparticles with different grain sizes. The photovoltaic properties and microstructures of solar cells were characterized. Nanoparticle sizes of these TiO2 were 23 nm and 3 nm and the performance of solar cells was improved by combination of two TiO2 nanoparticles

Fabrication and characterization of photovoltaic devices based on perovskite compounds with TiO2 nanoparticles

Perovskite-type photovoltaic devices were fabricated by a spin-coating method using a mixture solution. The compact and meso-porous TiO2 of the solar cells were fabricated from TiO2 nanoparticles and sol, and the photovoltaic properties and microstructures were characterized. The conversion efficiencies were improved by the combination of TiO2 nanoparticles and sol. Current density was also improved by increasing numbers of spin-coatings of meso-porous TiO2. Thick meso-porous TiO2 layers would assist the construction of perovskite layers and block of the leak current.

Fabrication and characterization of perovskite photovoltaic devices with TiO2 nanoparticle layers

TiO2/CH3NH3PbI3-based photovoltaic devices were fabricated by a spin-coating method using mixture solutions with TiO2 nanoparticles. Compact TiO2 layers were prepared from titanium diisopropoxide bis(acetyl acetonate) and TiO2 nanoparticles with different particle sizes. The performance of the photovoltaic devices was improved by sequential deposition of the TiO2 layers, which resulted in microstructural change of the perovskite layers.

Effects of Triphenylborane Addition to Decaphenylcyclopentasilane Thin Films

Organic thin film solar cells are potential ‘next generation’ solar cells. Many p-type semiconductors have been used in organic solar cells, but there have been far fewer reports involving n-type organic semiconductors. Developing new n-type organic semiconductors is therefore desirable. Decaphenylpentasilane (DPPS) thin films were spin-coated from solutions containing boron (B), and the effects of B addition on film microstructures and electronic properties were investigated. Microstructures of DPPS thin films were investigated by X-ray diffraction, and DPPS thin films doped with B (DPPS(B)) showed the reduction of crystallinity upon annealing at 300 °C, while DPPS thin films exhibited crystalline structures. DPPS(B) thin films exhibited decreased electrical resistances upon the B doping and annealing. The desorption of phenyl and methyl groups from the DPPS(B) thin films was observed by Raman scattering measurements.