Cs 2 NaInCl 6 double perovskite is stable, environmentally benign and easy to prepare. But it has a wide band gap (5.1 eV), and therefore, does not show optical and optoelectronic properties in the visible and short-wave infrared (SWIR) region. Here we introduce such functionalities in Cs 2 NaInCl 6 by codoping Sb 3 + (s-electron doping) and Er 3 + (f-electron doping) ions. Sb 3 + doping introduces optically allowed 5s 2 !5s 1 5p 1 electronic absorption at the sub-band gap level, which then emits blue photoluminescence with � 93 % quantum yield. But f-f electronic absorption of Er 3 + is parity forbidden. Codoping Sb 3 + -Er 3 + , leads to transfer of excitation energy from Sb 3 + to Er 3 + , yielding SWIR emission at 1540 nm. Temperature (6 to 300 K) dependent photoluminescence measurements elucidate the excitation and emission mechanism. A phosphor converted light emitting diode (pc-LED) fabricated by using the codoped sample emits stable blue and SWIR radiation over prolonged (84 hours) operation at 5.1 V.

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Cs 2 NaInCl 6 double perovskite is stable, environmentally benign and easy to prepare. But it has a wide band gap (5.1 eV), and therefore, does not show optical and optoelectronic properties in the visible and short-wave infrared (SWIR) region. Here we introduce such functionalities in Cs 2 NaInCl 6 by codoping Sb 3 + (s-electron doping) and Er 3 + (f-electron doping) ions. Sb 3 + doping introduces optically allowed 5s 2 !5s 1 5p 1 electronic absorption at the sub-band gap level, which then emits blue photoluminescence with � 93 % quantum yield. But f-f electronic absorption of Er 3 + is parity forbidden. Codoping Sb 3 + -Er 3 + , leads to transfer of excitation energy from Sb 3 + to Er 3 + , yielding SWIR emission at 1540 nm. Temperature (6 to 300 K) dependent photoluminescence measurements elucidate the excitation and emission mechanism. A phosphor converted light emitting diode (pc-LED) fabricated by using the codoped sample emits stable blue and SWIR radiation over prolonged (84 hours) operation at 5.1 V.

Here we have investigated the role of electron phonon coupling on the Raman spectrum of narrow bandgap semiconductors APd3O4 (A = Ca, Sr) and hole-doped system Sr0.85Li0.15Pd3O4. Four Raman active phonons are observed at room temperature for all three compounds as predicted by factor group analysis. The lowest energy phonon (∼190/202 cm−1) associated with Pd vibrations is observed to exhibit an asymmetric Fano-like lineshape in all the three compounds, indicating the presence of an interaction between the phonon and the electronic continuum. The origin of the electronic continuum states and electron–phonon coupling are discussed based on our laser power- and temperature-dependent Raman results. We have observed an enhanced strength of electron–phonon coupling in Sr0.85Li0.15Pd3O4 at low temperatures which can be attributed to the metallicity in this doped compound.

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