Poly(ethylene oxide)-assisted energy funneling for efficient perovskite light emission
[2];
[1];
[5];
[2]
- Southwest Univ., Chongqing (China)
- Univ. of Tennessee, Knoxville, TN (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Univ. of Tennessee, Knoxville, TN (United States); North Univ. of China, Shanxi (China)
- Southwest Univ., Chongqing (China); Univ. of Tennessee, Knoxville, TN (United States)
Poly(ethylene oxide) (PEO) has been demonstrated as an effective polymer additive for fabrication of organic–inorganic hybrid perovskite light emitting devices due to its properties enabling pinhole-free film morphology, improved charge injection, and defect passivation. In this paper, we report a new aspect of PEO in assisting the energy funneling in formamidinium lead bromide (FAPbBr3) thin films, leading to a very high photoluminescence quantum yield of ~62.1%. By mixing PEO with FAPbBr3 at a desired ratio, self-assembled 3D polycrystals with sizes from ~20 to ~1500 nm were formed. The polycrystals contain inhomogeneous domains with a range of energetic excited states. Through fluorescence lifetime image microscopy, the in situ fluorescence emissions and the lifetimes of the domains were measured simultaneously, indicating energy funneling from the wide-bandgap domains (with small-size grains) into the narrow-bandgap domains (with large-size grains). PL spectroscopy on the nano-second scale was used to study the dynamics of charge transfer, which shows a reduced short-wavelength emission and narrowed full width at half maximum with increasing time. Our results also indicate that the optimal PEO doping ratio of 0.35 :1 can facilitate the most efficient charge carrier cascade for energy funneling. Furthermore, this study establishes the role of PEO-assisted energy funneling avoiding the defect-quenching effect in perovskites, for potential applications in perovskite LEDs and lasers.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1566878
- Report Number(s):
- BNL--212140-2019-JAAM
- Journal Information:
- Journal of Materials Chemistry C, Journal Name: Journal of Materials Chemistry C Journal Issue: 27 Vol. 7; ISSN JMCCCX; ISSN 2050-7526
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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