Hybrid organic-inorganic metal halides of the type CHNHPbX have emerged as potential materials for photovoltaic applications. In this paper we discuss structural, electronic, and optical spectroscopy investigations performed on high quality single crystals of CHNHPbI. Our results conclusively suggest that CHNHPbI crystallizes in centrosymmetric space group and the methylammonium moiety exhibits disordered packing at room temperature. Extracted values of the exciton binding energy, the electron-phonon coupling constant, and the schematic energy level diagram constructed from the emission broadening, Raman, and photoemission spectroscopy measurements clearly show the potential of this system in photovoltaic applications.

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Gold clusters synthesized by the solution-based growth technique have exhibited ultraviolet (UV) light emission with nearly zero Stokes shift. Atomic arrangement decided optical properties of the Au microclusters have been studied extensively. In addition to the time-of-flight mass spectra, the comparison of experimental and theoretical emission and absorption spectra confirms the presence of Au8 clusters with the planar hexagon+1-shaped geometry. The observed UV emission is attributed to the transition from the highest occupied to the lowest unoccupied molecular orbitals of the hexagon+1 structured Au8 clusters.

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Molecular doping on graphene, through noncovalent functionalization offers a great opportunity to tune charge density on graphene for catalytic applications. Although enhanced oxygen reduction activity has been reported in heteroatom doped graphene, the synergistic advantage of molecular and heteroatom co-doping has not yet been studied. Here, we report the remarkably enhanced catalytic activity of benzoate or 1-pyrenebutyrate functionalized N-doped graphene (BA-NrGO/PB-NrGO) towards the oxygen reduction reaction (ORR) in alkaline medium. An efficient 4e(-) reduction process with a more positive onset potential (Eonset = 0.85 V vs. RHE) and high ORR activity (Jk = 3.16 mA cm(-2) at 0.65 V) has been observed in BA-NrGO. DFT studies show that the stimulated ORR activity is due to functionalisation induced increased charge density on active sites.