Sb3+-Er3+-Codoped Cs2NaInCl6 for Emitting Blue and Short-Wave Infrared Radiation

Cs2NaInCl6 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 Cs2NaInCl6 by codoping Sb3+ (s-electron doping) and Er3+ (f-electron doping) ions. Sb3+ doping introduces optically allowed 5s(2)-> 5s(1)5p(1) electronic absorption at the sub-band gap level, which then emits blue photoluminescence with approximate to 93 % quantum yield. But f-f electronic absorption of Er3+ is parity forbidden. Codoping Sb3+-Er3+, leads to transfer of excitation energy from Sb3+ to Er3+, 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.

Automated summary

Cs2NaInCl6 double perovskite is stable and environmentally benign, but does not show optical and optoelectronic properties in the visible and SWIR region due to its wide band gap. Codoping Sb3+ and Er3+ ions introduces new functionalities and enables the emission of blue and SWIR radiation in a fabricated phosphor converted LED.