Lead sulfide semiconducting thin films were chemically deposited on indium tin oxide coated glass plates for use as photoreceptor layers in conjugation with optically addressed spatial light modulators (OASLMs).

Using time-resolved photoluminescence spectroscopy over a wide range of temperatures, we were able to probe both radiative and nonradiative relaxation processes in luminescent porous silicon. By comparing the photoluminescence decay times from freshly prepared and oxidized porous silicon, we show that radiative processes should be linked with quantum confinement in small Si nanocrystallites and are not affected by oxidation. In contrast, nonradiative relaxation processes are associated with the state of oxidation where slower relaxation times characterize hydrogen-terminated porous silicon. These results are in a good agreement with the extended vibron model for small Si nanocrystallites.PACS78.55.Mb; 78.67.Rb; 78.47.jd

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A new route to formation of methylammonium lead iodide perovskite nanostructures is reported whose dimensions are controlled by the use of porous silicon nanotube templates. Optical absorption and photoluminescence properties for perovskite nanostructures of 70 and 200 nm in width are evaluated, along with comparisons with larger 1D microwires of the same composition.

One-dimensional organo-metal halide Perovskite (CH 3 NH 3 PbI 3 ) nanorods whose diameter and length are dictated by the inner size of porous silicon nanotube templates have been grown, characterized and compared to bulk perovskites in the form of microwires. We have observed a structural phase transition for bulk perovskites, where the crystal structure changes from tetragonal to orthorhombic at about 150K, as opposed to small diameter one-dimensional perovskite nanorods, of the order of 30-70 nm in diameter, where the phase transition is inhibited and the dominant phase remains tetragonal. Two major experimental techniques, infrared absorption spectroscopy and photoluminescence, were utilized to probe the temperature dependence of the perovskite phases over the 4-300K temperature range.Yet, different characteristics of the phase transition were measured by the two spectroscopic methods and explained by the presence of small, tetragonal inclusions embedded in the orthorhombic phase. The inhibition of the phase transition is attributed to the large surface area of these one-dimensional perovskite nanorods, which gives rise to a large stress that, in turn, prevents the formation of the orthorhombic phase. The absence of phase transition enables the measurement of the tetragonal bandgap energy down to low temperatures. *