Work

Pressure‐Enhanced Antiparallel Stacking Enables Full‐Visible‐Spectrum Piezochromism in MIL‐140B Nanocrystals

Year: 2026

Type: article

Abstract: Full-visible-spectrum piezochromic materials hold significant potential for applications in pressure sensing, smart displays and anti-counterfeiting. Polycyclic aromatic hydrocarbons (PAHs) have emerged as promising candidates owing to the inherent π-electron structure. However, the loose and parallel π-π stacking configuration leads to severe quenching of photoluminescence (PL). An effective approach is to construct PAHs into metal-organic frameworks (MOFs) to form an antiparallel π-π stacking arrangement. In this study, we demonstrate that MIL-140B nanocrystals (NCs) achieve full-visible-spectrum piezochromism during compression, with a substantial 212 nm PL bathochromic shift, which exceeds the PL range of all previously reported MOFs. Integrated experimental and computational analyses reveal that the organic linkage, 2,6-naphthalenedicarboxylic acid (NDC), in MIL-140B NCs form an antiparallel π-π stacking configuration at ambient conditions, thereby reducing the initial π-π conjugation and boosting the PL efficiency. The enhanced π-π stacking between NDC units under pressure progressively narrows the band gap, which enables full-visible-spectrum piezochromism. These findings not only highlight the potential of piezochromic MOFs, but also provide new perspectives for pressure-sensing under extreme conditions.

Source: Small

DOI: 10.1002/smll.76641