Self-Supporting Porous Silver Microspheres with Large Deformability for Low-Resistance Interconnection in Flexible Electronics

Electrical interconnection of high-density and flexible devices via conductive microparticles represents an effective solution. Achieving stable, low-resistance interfaces critically requires controlled conductive particle deformation during compression. However, conventional metal-coated polymer microspheres typically exhibit a deformation limit of ∼60%. Exceeding this threshold leads to shell fracture and sharply increased contact resistance, severely limiting conductivity. Here, we present self-supporting porous silver microspheres (PAg-MS) with an enhanced deformability and lower contact resistance. PAg-MS are synthesized via liquid-solid interfacial nonwetting spheroidization and dealloying. Nanoindentation experiments and theoretical calculations show that PAg-MS (porosity ≈ 51%) gradually densifies during compression and achieves high deformation exceeding 80%. This significantly increases the electrode contact area, shortens the conductive path, and reduces contact resistance to 0.023 Ω mm². Reliable LED array interconnections are demonstrated on both rigid and flexible substrates, highlighting the versatility of PAg-MS in diverse electronic systems.