Highly spectra-stable pure blue perovskite light-emitting diodes based on copper and potassium co-doped quantum dots

Halide perovskite light emitting diodes(LEDs)have gained great progress in recent years.However,mixed-halide perovskites for blue LEDs usually suffer from electroluminescence(EL)spectra shift at a high applied voltage or current density,limiting their efficiency.In this work,we report a strategy of using single-layer perovskite quantum dots(QDs)film to tackle the electroluminescence spectra shift in pure-blue perovskite LEDs and improve the LED efficiency by co-doping copper and potassium in the mixed-halide perovskite QDs.As a result,we obtained pure-blue halide perovskite QD-LEDs with stable EL spectra centred at 469 nm even at a current density of 1,617 mA·cm^(−2).The optimal device presents a maximum external quantum efficiency(EQE)of 2.0%.The average maximum EQE and luminance of the LEDs are 1.49%and 393 cd·m^(−2),increasing 62%and 66%compared with the control LEDs.Our study provides an effective strategy for achieving spectra-stable and highly efficient pure-blue perovskite LEDs.

Excitatory somatostatin interneurons in the dentate gyrus drive a widespread seizure network in cortical dysplasia

Seizures due to cortical dysplasia are notorious for their poor prognosis even with medications and surgery,likely due to the widespread seizure network.Previous studies have primarily focused on the disruption of dysplastic lesions,rather than remote regions such as the hippocampus.Here,we first quantified the epileptogenicity of the hippocampus in patients with late-stage cortical dysplasia.We further investigated the cellular substrates leading to the epileptic hippocampus,using multiscale tools including calcium imaging,optogenetics,immunohistochemistry and electrophysiology.For the first time,we revealed the role of hippocampal somatostatin-positive interneurons in cortical dysplasia-related seizures.Somatostatin-positive were recruited during cortical dysplasia-related seizures.Interestingly,optogenetic studies suggested that somatostatin-positive interneurons paradoxically facilitated seizure generalization.By contrast,parvalbumin-positive interneurons retained an inhibitory role as in controls.Electrophysiological recordings and immunohistochemical studies revealed glutamate-mediated excitatory transmission from somatostatin-positive interneurons in the dentate gyrus.Taken together,our study reveals a novel role of excitatory somatostatin-positive neurons in the seizure network and brings new insights into the cellular basis of cortical dysplasia.