Luminescent decay kinetics in a quasi-one-dimensional crystal, C5H10NH2PbI3

Photoluminescence and its decay kinetics for a single crystal of piperidinium triiodoplumbate C5H10NH2PbI3 have been investigated. The luminescent spectrum exhibits a single emission band at 2.1 eV with FWHM 0.3 eV, which has been attributed to a self-trapped exciton. The luminescent kinetics is discussed for the temperature range below 70 K, where the integrated luminescent intensity is almost constant. The exponential decay time τd apparently decreases from 44 μs at 5 K to ∼2 μs at 70 K while the initial intensity I0 increases by one order of magnitude, so that the product I0×τd is almost constant. Such a phenomenon is explained by assuming that the initial state of the luminescence consists of at least two sub-levels, between which population transfer is thermally achieved with an activation energy of 6 meV.