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Title: Tuning Emission and Electron–Phonon Coupling in Lead-Free Halide Double Perovskite Cs2AgBiCl6 under Pressure

Journal Article · · ACS Energy Letters
 [1];  [1];  [2];  [3]; ORCiD logo [4]; ORCiD logo [2];  [5]; ORCiD logo [1]
  1. Jilin Univ., Changchun (China). State Key Lab. of Superhard Materials
  2. Chinese Academy of Sciences, Dalian (China)
  3. Stanford Univ., CA (United States)
  4. Jilin Univ., Changchun (China). State Key Lab. of Superhard Materials; Stanford Univ., CA (United States)
  5. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)

Lead-free halide double perovskites have been proposed as candidates to replace Pb-halide perovskites in photovoltaic and optoelectronic applications due to their enhanced stability and nontoxicity. However, the limited understanding of the fundamental properties of halide double perovskites represents a hurdle to further improvement of their device performance. Our experimental studies demonstrate that the broad emission of Cs2AgBiCl6 with a large Stokes shift stems primarily from exciton self-trapping owing to strong electron–phonon coupling. We report an unusual blue shift of the emission accompanied by a red shift of the absorption edge occurred due to the reduced lattice relaxation energy upon lattice compression in the cubic phase. Electron–phonon coupling reduction is critical to the enhancement of photoluminescence intensity and tuning emission range in Cs2AgBiCl6 under high pressure. The structure–property relationships illuminated by our work can provide the basis for improving the performance of halide double perovskites.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
National Natural Science Foundation of China (NSFC); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1595140
Journal Information:
ACS Energy Letters, Journal Name: ACS Energy Letters Journal Issue: 12 Vol. 4; ISSN 2380-8195
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English