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General information

  • Name: Spiro-TTB
  • Full name: 2,2',7,7'-Tetra(N,N-di-p-tolyl)amino-9,9-spirobifluorene
  • CAS number: 515834-67-0
  • Chemical formula: C81H68N4
  • Molecular weight: 1097.43 g/mol
  • Absorption: λmax = 385 nm in THF
  • Photoluminescence: λmax = 409 nm in THF
  • HOMO/LUMO: HOMO = 5.2 eV, LUMO = 1.9 eV
  • Synonyms: N2,N2,N2′,N2′,N7,N7,N7′,N7′-Octa-p-tolyl-9,9′-spirobi[fluorene]-2,2′,7,7′-tetraamine, 2,2′,7,7′-Tetra(N, N-di-tolyl)amino-spiro-bifluorene
  • Classification: Organic light-emitting diodes, Hole transport layer materials (HTL), Perovskite solar cells, Organic photovoltaic devices
  • Purity: >98.0% (HPLC)
  • Melting point: Tg = 146 °C
  • Appearance: Light yellow powder/crystals

Spiro-TTB: Advancing the Field of Organic Light-Emitting Devices

The organic electronics sector is witnessing rapid advancements and Spiro-TTB is at the forefront of these innovations. Recognized for its electron-rich structure and versatility, Spiro-TTB is making significant strides in the development of OLED devices, perovskite solar cells and other organic photovoltaic devices.

Understanding Spiro-TTB

Spiro-TTB, scientifically known as 2,2′,7,7′-Tetra(N,N-di-p-tolyl)amino-9,9-spirobifluorene, is derived from a core of spirobifluorene with di-p-tolylamines attached at the 2- and 7-positions. This unique molecular configuration imparts an electron-rich nature to the compound, making it an ideal candidate for various optoelectronic applications.

Key Features of Spiro-TTB

  • Hole Transport Layer (HTL) Material: Spiro-TTB’s electron-rich structure makes it a prime choice for use as a hole transport layer in OLED devices. Its ability to effectively transport holes ensures optimal device performance.
  • Electron Blocking Layer (EBL) Material: Its properties also allow it to serve as an electron blocking layer, preventing unwanted electron movement and enhancing device efficiency.
  • Host Material in PhOLEDs: Spiro-TTB is extensively used in phosphorescent organic light-emitting diodes (PhOLEDs) as a host material, facilitating better light emission and device longevity.
  • Compatibility with Perovskite Solar Cells and OPVs: Beyond OLEDs, Spiro-TTB finds applications in perovskite solar cells and organic photovoltaic devices, underscoring its versatility in the organic electronics domain.

Spiro-TTB in Organic Electronics

Spiro-TTB’s prominence in the organic electronics sector is not just due to its molecular structure but also its adaptability. When compared to other compounds like Spiro-OMeTAD, Spiro-TTB showcases a deeper HOMO energy level, which can potentially lead to enhanced device performance. Its ability to form exciplexes with other materials further broadens its application scope, making it a valuable asset in the research and development of next-generation organic electronic devices.


Spiro-TTB is shaping the future of organic electronics with its multifaceted applications and unique molecular attributes. As research continues to delve deeper into its potential, Spiro-TTB is poised to set new benchmarks in the OLED and organic photovoltaic sectors.

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