Recently, Wu Wentiao, a senior undergraduate from the School of Space Science and Physics, published a paper as the front cover in the Journal of “Phys.Chem.Chem.Phys.”, which is entitled as“Investigation of the Mn dopant-enhanced photoluminescence performance of lead-free Cs₂AgInCl₆ double perovskite crystals”.The first author is Wu Wentiao,and the corresponding author is Lu Yingbo who is a teacher from the School of Space Science and Physics,SDU.The impact factor of this journal is 3.567,which is classified as Q1 journal from JCR.

Investigations about energy and environmental have received widespread attention today,and the demand for the new photovoltaic materials increases gradually.For example,we can get clean power from solar cells,LED can improve the energy efficiency.Researches related to the perovskite materials are extensive in these field.The double perovskite materials,which are non-toxic and show good stability,come to the stage.Previous researches indicate that the double perovskite materials have important applications in the solar cells and LED materials.Wu Wentiao investigated the luminescence performances of the Mn-doped Cs₂AgInCl₆double perovskite materials.By means of the first principle calculations, authors study the distribution of Mn dopants in the double perovskite lattice.The variation of the lattice induced by dopant is also discussed through analyses of the charge balance and localized lattice strain.There is no significant change for the bandgap of Cs₂AgInCl₆ double perovskite materials brought by the Mn dopant.However,Mn dopant generates two impurity bands in the forbidden band,which originates from the 3d orbitals and is assigned as the first excited state(⁴T₁) and the ground state (⁶A₁) of Mn²⁺ions.It is the transition between these two energy bands, i.e., d-d transition,makes the Cs₂AgInCl₆ double perovskite materials produce a photoluminescence peak (632nm) that is less than the bandgap of the host materials.Although Cs₂AgInCl₆ materials possess a direct bandgap,it has the same parity at theΓpoints of CBM and VBM.Therefore,the optical transition is forbidden,resulting in the low quantum efficiency of its band-band emission (only 1.6%).However,the d-d transition induced by Mn dopant in the Cs₂AgInCl₆ materials breaks the parity forbidden,so the quantum yield of this transition increases greatly,with a high value of 16%.This article explains the Mn enhanced luminescence of Cs₂AgInCl₆ materials and provides useful information for their applications in the field of LED.

The School of Space Science and Physics pays high emphasis to promote the innovative ability of the undergraduates.With the help of the Undergraduate Tutor System and the Scientific Research Project for Undergraduates,they build a collaborative training system to push the undergraduates into the teachers’scientific research team.Moreover,they open the labs to the talented students and fund their high-edged scientific research.The School of Space Science and Physics also organize students to participate in various scientific and technological innovation competition projects,such as the“Challenge Cup” National Undergraduate Curricular Academic Science and Technology Works, Physical Science and Technology Innovation Competition, etc.By these activities,they promoted the innovation ability of the undergraduate students and achieved fruitful results.Benefiting from these aforementioned projects,Wu Wentiao entered the laboratory very early and performed a long-termed scientific research guided by the tutors.During the period engaging in scientific research,Wu studied hard and acquired knowledge quickly,therefore,he has won lots of national and provincial awards for undergraduates or other achievements.

This work was supported by the National Natural Science Foundation of China,the Shandong Provincial Natural Science Foundation,the Weihai Key Laboratory and the Supercomputing Center of Shandong University (Weihai).

Paper Link:Investigation of the Mn dopant-enhanced photoluminescence performance of lead-free Cs2AgInCl6 double perovskite crystals

Written by：Lu Yingbo

Edited by: Che Huiqing