Rigid π‐Bridge Conformational Locked Crosslinker for Non‐Destructive Direct Photopatterning of Colloidal Quantum Dot

ABSTRACT

Colloidal quantum dots (QDs) are promising emitters for next‐generation displays, yet direct photolithography often causes severe photophysical degradation that compromises device performance. Although molecular rigidification can alleviate photodamage, it usually reduces crosslinker solubility, limiting compatibility with octane‐dispersed QDs. Here, we propose a conformation‐locked π‐bridge design that simultaneously enhances molecular rigidity and solubility. Using fluorinated phenyl (F1) and biphenyl (F2) π‐bridge crosslinkers as model systems, we reveal how conformational regulation governs QD photopatterning. The conformation‐locked F2 suppresses molecular torsion while maintaining excellent octane solubility, enabling high‐fidelity photopatterning with a resolution of 12,700 PPI. Meanwhile, the extended π‐conjugation increases its molar extinction coefficient to 77,598 L mol ⁻¹ cm ⁻¹ , reducing the required UV exposure dose to 2 mJ cm ⁻² . As a result, patterned QDs retain over 95% of their photoluminescence quantum yield and 97% of their fluorescence lifetime. QLEDs fabricated from F2‐patterned QDs exhibit an external quantum efficiency of 24.40% and a maximum luminance of 237,692 cd m ⁻² , with both performance metrics essentially preserved after patterning. Furthermore, the enhanced exciton binding energy significantly improves operational stability, extending the device lifetime (T ₉₅ ) from 421 h to 2,324 h at 1,000 cd m ⁻² . This work provides a general strategy for low‐dose, non‐destructive, high‐resolution QD photolithography.