Nanoscale transfer-printed full-colour ultrahigh-resolution quantum dot LEDs

a, Static contact angles measured on the PVB surface before (i) and after (ii) oxygen plasma treatment and on the Si template before (iii) and after (iv) silanization, illustrating the controlled tuning of interfacial wettability required for reliable imprinting and subsequent release. b, Dependence of the PVA sacrificial layer thickness on solution concentration under fixed spin-coating conditions. c, Correlation between the thickness of the PVB/PVA bilayer, imprinting time using the Si template and the PDMS stamp temperature, highlighting the coupled thermal–mechanical conditions necessary for faithful microhole formation and replication. d, Pattern transfer yield as a function of PVB concentration, in which red spheres denote the adhesion force between the Si template and the PVB layer during imprinting and black spheres denote the adhesion force during separation of the PDMS stamp from the PVB layer after transfer, revealing the critical balance between imprint fidelity and release efficiency. e, Dependence of pattern transfer yield on the target substrate temperature and imprinting time during transfer of the patterned QD array. f, Pattern transfer yield as a function of applied pressure and target substrate temperature, identifying the optimal process window for achieving high-yield and defect-free transfer.