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Good quality thin films of poly(2,5-bis(2′-ethyl-hexyl)–1,4-phenylenevinylene) (BEH–PPV) were optically characterized by photoluminescence, absorption, and Raman scattering techniques. The temperature evolution of the vibronic structures in the photoluminescence and absorption spectra was analyzed. At low temperatures it was possible to identify the different phonon modes that contribute to the vibronic spectra. The correlation of the Raman and photoluminescence spectra enabled us to conclude that the main vibrational modes are the two most intense Raman bands at 1310 and 1579 cm−1. The emission efficiency highly increases and the absorption spectra become much more resolved with decreasing temperature. The temperature dependence of the zero-phonon line in the absorption and photoluminescence measurements is attributed to an increase of the effective conjugation length at low temperatures. The results from the polarization-resolved photoluminescence demonstrated the high degree of the in-plane structural order in the BEH–PPV films, corroborating to the relatively high conjugation length obtained from the analysis of the Huang–Rhys factor.

Small size microcavity pillars with elliptical cross section and high quality factors Q are reported and are shown to provide nearly 100% linearly polarized single photon sources. It is shown that the polarization of the emission of quantum dots embedded within the pillars can be controlled by using the coupling of the dot emission with the photonic modes. A notable dependence of the Q value is found on the polarization of the mode even though calculations of the mode profiles show that the electric field distribution is very similar.

In this work, we demonstrate the nanofabrication of monolayer MoS2 islands using local anodic oxidation of few-layer and bulk MoS2 flakes. The nanofabricated islands present true monolayer Raman signal and photoluminescence intensity up to two orders of magnitude larger than that of a pristine monolayer. This technique is robust enough to result in monolayer islands without the need of meticulously fine-tuning the oxidation process, thus providing a fast and reliable way of creating monolayer regions with enhanced optical properties and with controllable size, shape, and position.