Limits to Electrical Mobility in Lead-Halide Perovskite Semiconductors.

Semiconducting polycrystalline thin films are cheap to produce and can be deposited on flexible substrates, yet high-performance electronic devices usually utilize single-crystal semiconductors, owing to their superior charge-carrier mobilities and longer diffusion lengths. Here we show that the electrical performance of polycrystalline films of metal-halide perovskites (MHPs) approaches that of single crystals at room temperature. Combining temperature-dependent terahertz conductivity measurements and ab initio calculations we uncover a complete picture of the origins of charge-carrier scattering in single crystals and polycrystalline films of CHNHPbI.

The Effects of Doping Density and Temperature on the Optoelectronic Properties of Formamidinium Tin Triiodide Thin Films.

Optoelectronic properties are unraveled for formamidinium tin triiodide (FASnI ) thin films, whose background hole doping density is varied through SnF addition during film fabrication. Monomolecular charge-carrier recombination exhibits both a dopant-mediated part that grows linearly with hole doping density and remnant contributions that remain under tin-enriched processing conditions. At hole densities near 10 cm , a strong Burstein-Moss effect increases absorption onset energies by ≈300 meV beyond the bandgap energy of undoped FASnI (shown to be 1.

Impact of the Organic Cation on the Optoelectronic Properties of Formamidinium Lead Triiodide.

Metal halide perovskites have proven to be excellent light-harvesting materials in photovoltaic devices whose efficiencies are rapidly improving. Here, we examine the temperature-dependent photon absorption, exciton binding energy, and band gap of FAPbI (thin film) and find remarkably different behavior across the β-γ phase transition compared with MAPbI. While MAPbI has shown abrupt changes in the band gap and exciton binding energy, values for FAPbI vary smoothly over a range of 100-160 K in accordance with a more gradual transition.

Abnormal sebaceous gland differentiation in 10 kittens ('sebaceous gland dysplasia') associated with generalized hypotrichosis and scaling.

A rare congenital dermatosis, characterized by progressive hypotrichosis with variable scaling and crusting, occurred in 10 short-haired kittens in North America and Europe. Lesions appeared at between 4 and 12 weeks of age, commencing on the head and becoming generalized. The tail was spared in two kittens.

Direct WIMP detection with cryogenic detectors.

Cryogenic detectors have been developed since the mid 1980s and have been applied successfully to dark-matter searches since the mid 1990s. Among the advantages of cryogenic detectors are their high sensitivity to nuclear recoil, their low detection thresholds, the wide choice of target materials and the possibility of implementing event type recognition on an event-by-event basis. I explain the basics of cryogenic detectors, review various implementations, discuss advantages and drawbacks and give an overview of current dark-matter-search experiments based upon cryogenic detectors.