We report on the temperature dependence of thermal conductivity of single crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The comparable absolute values and temperature dependence of the two samples’ morphologies indicate the minor role of the grain boundaries on the heat transport. Theoretical modeling demonstrates the importance of the resonant scattering in both specimens. The interaction between phonon waves and rotational degrees of freedom of CH3NH3 + sublattice emerges as the dominant mechanism for attenuation of heat transport and for ultralow thermal conductivity of 0.5 W/(Km) at room temperature.

We report the synthesis of Methylammonium Lead Iodide (CH(3)NH(3)PbI(3)) nanowires by a low temperature solution processed crystallization using a simple slip-coating method. The anisotropic particle shape exhibits advantages over nanoparticles in terms of charge transport under illumination. These results provide a basis for solvent-mediated tailoring of structural properties like the crystallite size and orientation in trihalide perovskite thin films, which, once implemented into a device, may ultimately result in an enhanced charge carrier extraction.

The hybrid halide perovskites, the very performant compounds in photovoltaic applications, possess large Seebeck coefficient and low thermal conductivity making them potentially interesting high figure of merit (ZT) materials. For this purpose one needs to tune the electrical conductivity of these semiconductors to higher values. We have studied the CH3NH3MI3 (M=Pb,Sn) samples in pristine form showing very low ZT values for both materials; however, photoinduced doping (in M=Pb) and chemical doping (in M=Sn) indicate that, by further doping optimization, ZT can be enhanced toward unity and reach the performance level of the presently most efficient thermoelectric materials.X. Mettan et al. 04.26.2015 1

The first hybrid phototransistors are reported where the performance of a network of photoactive CH3NH3PbI3 nanowires is enhanced by CVD‐grown monolayer graphene. These devices show responsivities as high as ≈2.6 × 106 A W−1 in the visible range, showing potential as room‐temperature single‐electron detectors.

Titanate nanowires were synthesized through the hydrothermal synthesis route (10 M NaOH, 130 °C) from anatase in a rotating autoclave. A combined TEM, SEM, XRD, FT−Raman, and N2 adsorption investigation of the reaction products as a function of time revealed that the 60−150 nm wide and ∼5 μm long nanowires are in fact formed by the merging of self-assembled nanotube bundles. The nanowires are able to further self-assemble into ∼5 μm wide and longer than 30 μm long, dense “superbundles” if the reaction is allowed to run long enough. We propose that the spontaneous nanotube arrangement could be caused by the rotation-assisted oriented attachment of the tubes.