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Unraveling emission narrowing pathways in N-embedded polyaromatic systems via sequential π-interlocking for efficient
Danish Khan1, Seungwon Han2, Keerthika P3
1Organic Materials Laboratory (OM-Lab), Department of Chemistry, Indian Institute of Technology-Patna Bihta Kanpa Rd Patna, Dayalpur Daulatpur Bihar 801106 India rajsan@iitp.ac.in rkonidena531@gmail.com.
Chemical Science
|June 17, 2026
Summary
Researchers developed a molecular design strategy using sequential π-interlocking to create efficient, narrowband organic emitters for organic light-emitting diodes (OLEDs). This method precisely controls emission bandwidth, leading to improved device performance and pure ultraviolet emission.
Area of Science:
- Materials Science
- Organic Electronics
- Photophysics
Background:
- Growing demand for complex, boron-free, narrowband organic emitters for organic light-emitting diodes (OLEDs).
- Challenges in controlling vibronic coupling and structural relaxation for precise emission bandwidth tuning.
- Limited success in developing efficient narrowband emitters without sacrificing performance.
Purpose of the Study:
- To present a molecular design strategy for regulating emission bandwidth in N-embedded polyaromatic hydrocarbons (N-PAHs).
- To investigate the effect of sequential π-interlocking on molecular geometry, vibronic coupling, and structural relaxation.
- To develop efficient, boron-free, narrowband organic emitters for OLED applications.
Main Methods:
- Synthesis of a library of N-PAH emitters (CzTPA, CzCz, CzICz, ICzICz) with varying degrees of π-interlocking.
- Combined photophysical characterization and density functional theory (DFT) calculations.
- Fabrication and testing of organic light-emitting diodes (OLEDs) using the synthesized emitters.
Main Results:
- Stepwise π-interlocking rigidifies molecular geometry, suppresses vibronic coupling, and minimizes structural relaxation.
- Emission bandwidth (FWHM) narrows progressively from 58 nm to 24 nm across the series, with blue-shifted emission.
- The ICzICz emitter shows a narrow FWHM of ~24 nm, high photoluminescence quantum yield (PLQY) of ~92%, and enables pure UV emission in OLEDs (EQE 4.2%).
- As a host for green phosphors, the device achieves high EQE (~18.5%) with minimal roll-off.
Conclusions:
- Sequential π-interlocking is an effective molecular design strategy for controlling emission bandwidth in N-PAHs.
- This approach yields efficient, boron-free, narrowband organic emitters with tunable properties for OLEDs.
- The developed molecular design toolkit offers a pathway to advanced organic electronic materials.
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