Temperature Dependent Photoluminescence Properties Of Inorganic Perovskite Quantum Dots Doped With Mn Ions

All inorganic CsPbX₃?X=Cl,Br,I?quantum dots have cubic perovskite structure.By changing the content of halogen elements,the band gap width of quantum dots can be adjusted so that the luminescence peaks of the quantum dots can be adjustable to cover the visible light range.And perovskite materials with high luminous efficiency,narrow half peak width,it has good application prospects in the field of solar cell.Recent studies show that the size of the perovskite quantum dots is reduced,which can effectively reduce the number of internal defects and reduce the nonradiative transition,which is expected to improve the fluorescence efficiency.In addition,when the quantum dot size is close to the Bohr radius,It may lead to the transition from"free electron hole compound"to"exciton compound"mode,which is also a favorable factor for high luminescence efficiency.Therefore,how to control the size and morphology of perovskite materials has become a new challenge in perovskite materials research.In 2016,J Am Chem Soc and Nano Lett respectively reported the synthesis of the perovskite quantum dots doped with Mn²⁺ions and the double light emission of excitons and Mn ions,and the problem of short service life caused by the dissociation of perovskite quantum dots was effectively solved.Through the replacement of materials,the perovskite nanocrystals doped with Mn²⁺ions improve the stability of the devices,which will prompt the rapid development of the perovskite quantum dot optoelectronic devices.In this paper,CsPbX₃?X=Cl,Br,I?and Mn²⁺ions doped nanocrystals were synthesized by the method of heat injection.The Mn:CsPbCl₃ quantum dots with different Mn doping concentration and different sizes were obtained.The mechanism of luminescence and the degradation process of heat treatment were studied.The research work in this paper includes the following three parts.?1?Mn²⁺ion luminescence mechanism of Mn:CsPbCl₃ quantum dots doped with different Mn²⁺concentrations.Different concentrations of Mn:CsPbCl₃ quantum dots were synthesized,and the PL emissions of different concentration quantum dots were characterized.The PL lifetimes of Mn²⁺ions were tested.It is found that the concentration of Mn²⁺ion has an essential influence on the luminous efficiency.The luminescence of Mn²⁺ions is derived from the energy transfer with the band edge.The luminescence of Mn²⁺ions is abnormal.?2?Band edge emissin mechanism of Mn:CsPbCl₃ quantum dots.The Mn:CsPbCl₃ quantum dots with different concentrations were synthesized and the luminescence of different concentrations of quantum dots was characterized.The PL lifetimes of the Mn²⁺ions and the band edge were measured.It is found that the concentration of Mn²⁺ion has a significant effect on the lifetimes of band edge excitons.?3?Luminescence properties of Mn:CsPbCl₃ quantum dots with different sizes.The Mn:CsPbCl₃ quantum dots of different sizes were synthesized,and their luminescence properties were characterized.The PL lifetime of the Mn²⁺ions and band edge excitons were measured.It is found that thesize effect is not important for PL lifetimes of Mn²⁺ions,but the size has a certain effect on the PL lifetime of the bandedge excitons.