truFLEX® 6 layer stack for backplane technology

SmartKem has developed the complete truFlex® Stack

  • Composed of 6 layers: BL (Base Layer), SAM (Self-Assembled Monolayer), OSC (Organic Semiconductor), OGI (Organic Gate Insulator), SRL (Sputter Resistant Layer, PL (Passivation Layer).
  • Low mask count and low temperature coating processes, making the fabrication process economically favourable versus vacuum coating processes.
  • The material stack is compatible with industry standard sputter deposition processes and etching, stripping solutions.
  • truFLEX® can be optimised for all voltage or current driven front-plane technologies including EPD, LCD & OLED.
  • The material set is printable and plastic compatible, enabling robust, flexible devices to be made on a large area.

Base Layer (BL)

  • Affords planarisation of substrate
  • Chemistry of BL is matched to the Carrier Injection Modification layer and to the OSC ink, enabling highly uniform OSC ink morphology even in large area deposition

Passivation Layer (PL)

  • Photocurable layer, designed to impart chemical resistance and physical integrity to the OTFT stack

Organic Semiconductor (OSC)

  • OSC is the charge transporting material, determines mobility.

Sputter Resistant Layer (SRL)

  • Photocurable, highly crosslinked organic polymer layer. Designed to provide resistance of OGI and OSC to sputter damage. Enables deposition of a wide range of gate materials including Mo/Al/Mo.

Organic Gate Insulator (OGI)

  • Key interface with OSC. Permittivity of OGI material determines carrier density in channel and influences device hysteresis.

Carrier Injection Modification Layer (SAM)

  • Self assembled monolayer that modifies the work function and surface chemistry of electrodes. Controls charge injection into OSC and uniformity of OSC.



Low current usage


Low process temperature


Wide substrate compatibility


Current driving stability


Impact resistance


Small bend radius